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cpython/Python/compile.c

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/*
* This file compiles an abstract syntax tree (AST) into Python bytecode.
*
* The primary entry point is PyAST_Compile(), which returns a
* PyCodeObject. The compiler makes several passes to build the code
* object:
* 1. Checks for future statements. See future.c
* 2. Builds a symbol table. See symtable.c.
* 3. Generate code for basic blocks. See compiler_mod() in this file.
* 4. Assemble the basic blocks into final code. See assemble() in
* this file.
* 5. Optimize the byte code (peephole optimizations). See peephole.c
*
* Note that compiler_mod() suggests module, but the module ast type
* (mod_ty) has cases for expressions and interactive statements.
*
* CAUTION: The VISIT_* macros abort the current function when they
* encounter a problem. So don't invoke them when there is memory
* which needs to be released. Code blocks are OK, as the compiler
* structure takes care of releasing those. Use the arena to manage
* objects.
*/
#include "Python.h"
#include "Python-ast.h"
#include "node.h"
#include "pyarena.h"
#include "ast.h"
#include "code.h"
#include "compile.h"
#include "symtable.h"
#include "opcode.h"
int Py_OptimizeFlag = 0;
#define DEFAULT_BLOCK_SIZE 16
#define DEFAULT_BLOCKS 8
#define DEFAULT_CODE_SIZE 128
#define DEFAULT_LNOTAB_SIZE 16
struct instr {
unsigned i_jabs : 1;
unsigned i_jrel : 1;
unsigned i_hasarg : 1;
unsigned char i_opcode;
int i_oparg;
struct basicblock_ *i_target; /* target block (if jump instruction) */
int i_lineno;
};
typedef struct basicblock_ {
/* Each basicblock in a compilation unit is linked via b_list in the
reverse order that the block are allocated. b_list points to the next
block, not to be confused with b_next, which is next by control flow. */
struct basicblock_ *b_list;
/* number of instructions used */
int b_iused;
/* length of instruction array (b_instr) */
int b_ialloc;
/* pointer to an array of instructions, initially NULL */
struct instr *b_instr;
/* If b_next is non-NULL, it is a pointer to the next
block reached by normal control flow. */
struct basicblock_ *b_next;
/* b_seen is used to perform a DFS of basicblocks. */
unsigned b_seen : 1;
/* b_return is true if a RETURN_VALUE opcode is inserted. */
unsigned b_return : 1;
/* depth of stack upon entry of block, computed by stackdepth() */
int b_startdepth;
/* instruction offset for block, computed by assemble_jump_offsets() */
int b_offset;
} basicblock;
/* fblockinfo tracks the current frame block.
A frame block is used to handle loops, try/except, and try/finally.
It's called a frame block to distinguish it from a basic block in the
compiler IR.
*/
enum fblocktype { LOOP, EXCEPT, FINALLY_TRY, FINALLY_END };
struct fblockinfo {
enum fblocktype fb_type;
basicblock *fb_block;
};
/* The following items change on entry and exit of code blocks.
They must be saved and restored when returning to a block.
*/
struct compiler_unit {
PySTEntryObject *u_ste;
PyObject *u_name;
/* The following fields are dicts that map objects to
the index of them in co_XXX. The index is used as
the argument for opcodes that refer to those collections.
*/
PyObject *u_consts; /* all constants */
PyObject *u_names; /* all names */
PyObject *u_varnames; /* local variables */
PyObject *u_cellvars; /* cell variables */
PyObject *u_freevars; /* free variables */
PyObject *u_private; /* for private name mangling */
int u_argcount; /* number of arguments for block */
/* Pointer to the most recently allocated block. By following b_list
members, you can reach all early allocated blocks. */
basicblock *u_blocks;
basicblock *u_curblock; /* pointer to current block */
int u_nfblocks;
struct fblockinfo u_fblock[CO_MAXBLOCKS];
int u_firstlineno; /* the first lineno of the block */
int u_lineno; /* the lineno for the current stmt */
bool u_lineno_set; /* boolean to indicate whether instr
has been generated with current lineno */
};
/* This struct captures the global state of a compilation.
The u pointer points to the current compilation unit, while units
for enclosing blocks are stored in c_stack. The u and c_stack are
managed by compiler_enter_scope() and compiler_exit_scope().
*/
struct compiler {
const char *c_filename;
struct symtable *c_st;
PyFutureFeatures *c_future; /* pointer to module's __future__ */
PyCompilerFlags *c_flags;
int c_interactive; /* true if in interactive mode */
int c_nestlevel;
struct compiler_unit *u; /* compiler state for current block */
PyObject *c_stack; /* Python list holding compiler_unit ptrs */
PyArena *c_arena; /* pointer to memory allocation arena */
};
static int compiler_enter_scope(struct compiler *, identifier, void *, int);
static void compiler_free(struct compiler *);
static basicblock *compiler_new_block(struct compiler *);
static int compiler_next_instr(struct compiler *, basicblock *);
static int compiler_addop(struct compiler *, int);
static int compiler_addop_o(struct compiler *, int, PyObject *, PyObject *);
static int compiler_addop_i(struct compiler *, int, int);
static int compiler_addop_j(struct compiler *, int, basicblock *, int);
static basicblock *compiler_use_new_block(struct compiler *);
static int compiler_error(struct compiler *, const char *);
static int compiler_nameop(struct compiler *, identifier, expr_context_ty);
static PyCodeObject *compiler_mod(struct compiler *, mod_ty);
static int compiler_visit_stmt(struct compiler *, stmt_ty);
static int compiler_visit_keyword(struct compiler *, keyword_ty);
static int compiler_visit_expr(struct compiler *, expr_ty);
static int compiler_augassign(struct compiler *, stmt_ty);
static int compiler_visit_slice(struct compiler *, slice_ty,
expr_context_ty);
static int compiler_push_fblock(struct compiler *, enum fblocktype,
basicblock *);
static void compiler_pop_fblock(struct compiler *, enum fblocktype,
basicblock *);
/* Returns true if there is a loop on the fblock stack. */
static int compiler_in_loop(struct compiler *);
static int inplace_binop(struct compiler *, operator_ty);
static int expr_constant(expr_ty e);
static int compiler_with(struct compiler *, stmt_ty);
static PyCodeObject *assemble(struct compiler *, int addNone);
static PyObject *__doc__;
PyObject *
_Py_Mangle(PyObject *privateobj, PyObject *ident)
{
/* Name mangling: __private becomes _classname__private.
This is independent from how the name is used. */
const char *p, *name = PyString_AsString(ident);
char *buffer;
size_t nlen, plen;
if (privateobj == NULL || !PyString_Check(privateobj) ||
name == NULL || name[0] != '_' || name[1] != '_') {
Py_INCREF(ident);
return ident;
}
p = PyString_AsString(privateobj);
nlen = strlen(name);
/* Don't mangle __id__ or names with dots.
The only time a name with a dot can occur is when
we are compiling an import statement that has a
package name.
TODO(jhylton): Decide whether we want to support
mangling of the module name, e.g. __M.X.
*/
if ((name[nlen-1] == '_' && name[nlen-2] == '_')
|| strchr(name, '.')) {
Py_INCREF(ident);
return ident; /* Don't mangle __whatever__ */
}
/* Strip leading underscores from class name */
while (*p == '_')
p++;
if (*p == '\0') {
Py_INCREF(ident);
return ident; /* Don't mangle if class is just underscores */
}
plen = strlen(p);
assert(1 <= PY_SSIZE_T_MAX - nlen);
assert(1 + nlen <= PY_SSIZE_T_MAX - plen);
ident = PyString_FromStringAndSize(NULL, 1 + nlen + plen);
if (!ident)
return 0;
/* ident = "_" + p[:plen] + name # i.e. 1+plen+nlen bytes */
buffer = PyString_AS_STRING(ident);
buffer[0] = '_';
strncpy(buffer+1, p, plen);
strcpy(buffer+1+plen, name);
return ident;
}
static int
compiler_init(struct compiler *c)
{
memset(c, 0, sizeof(struct compiler));
c->c_stack = PyList_New(0);
if (!c->c_stack)
return 0;
return 1;
}
PyCodeObject *
PyAST_Compile(mod_ty mod, const char *filename, PyCompilerFlags *flags,
PyArena *arena)
{
struct compiler c;
PyCodeObject *co = NULL;
PyCompilerFlags local_flags;
int merged;
if (!__doc__) {
__doc__ = PyString_InternFromString("__doc__");
if (!__doc__)
return NULL;
}
if (!compiler_init(&c))
return NULL;
c.c_filename = filename;
c.c_arena = arena;
c.c_future = PyFuture_FromAST(mod, filename);
if (c.c_future == NULL)
goto finally;
if (!flags) {
local_flags.cf_flags = 0;
flags = &local_flags;
}
merged = c.c_future->ff_features | flags->cf_flags;
c.c_future->ff_features = merged;
flags->cf_flags = merged;
c.c_flags = flags;
c.c_nestlevel = 0;
c.c_st = PySymtable_Build(mod, filename, c.c_future);
if (c.c_st == NULL) {
if (!PyErr_Occurred())
PyErr_SetString(PyExc_SystemError, "no symtable");
goto finally;
}
co = compiler_mod(&c, mod);
finally:
compiler_free(&c);
assert(co || PyErr_Occurred());
return co;
}
PyCodeObject *
PyNode_Compile(struct _node *n, const char *filename)
{
PyCodeObject *co = NULL;
mod_ty mod;
PyArena *arena = PyArena_New();
if (!arena)
return NULL;
mod = PyAST_FromNode(n, NULL, filename, arena);
if (mod)
co = PyAST_Compile(mod, filename, NULL, arena);
PyArena_Free(arena);
return co;
}
static void
compiler_free(struct compiler *c)
{
if (c->c_st)
PySymtable_Free(c->c_st);
if (c->c_future)
PyObject_Free(c->c_future);
Py_DECREF(c->c_stack);
}
static PyObject *
list2dict(PyObject *list)
{
Py_ssize_t i, n;
PyObject *v, *k;
PyObject *dict = PyDict_New();
if (!dict) return NULL;
n = PyList_Size(list);
for (i = 0; i < n; i++) {
v = PyInt_FromLong(i);
if (!v) {
Py_DECREF(dict);
return NULL;
}
k = PyList_GET_ITEM(list, i);
k = PyTuple_Pack(2, k, k->ob_type);
if (k == NULL || PyDict_SetItem(dict, k, v) < 0) {
Py_XDECREF(k);
Py_DECREF(v);
Py_DECREF(dict);
return NULL;
}
Py_DECREF(k);
Py_DECREF(v);
}
return dict;
}
/* Return new dict containing names from src that match scope(s).
src is a symbol table dictionary. If the scope of a name matches
either scope_type or flag is set, insert it into the new dict. The
values are integers, starting at offset and increasing by one for
each key.
*/
static PyObject *
dictbytype(PyObject *src, int scope_type, int flag, int offset)
{
Py_ssize_t pos = 0, i = offset, scope;
PyObject *k, *v, *dest = PyDict_New();
assert(offset >= 0);
if (dest == NULL)
return NULL;
while (PyDict_Next(src, &pos, &k, &v)) {
/* XXX this should probably be a macro in symtable.h */
assert(PyInt_Check(v));
scope = (PyInt_AS_LONG(v) >> SCOPE_OFF) & SCOPE_MASK;
if (scope == scope_type || PyInt_AS_LONG(v) & flag) {
PyObject *tuple, *item = PyInt_FromLong(i);
if (item == NULL) {
Py_DECREF(dest);
return NULL;
}
i++;
tuple = PyTuple_Pack(2, k, k->ob_type);
if (!tuple || PyDict_SetItem(dest, tuple, item) < 0) {
Py_DECREF(item);
Py_DECREF(dest);
Py_XDECREF(tuple);
return NULL;
}
Py_DECREF(item);
Py_DECREF(tuple);
}
}
return dest;
}
static void
compiler_unit_check(struct compiler_unit *u)
{
basicblock *block;
for (block = u->u_blocks; block != NULL; block = block->b_list) {
assert((void *)block != (void *)0xcbcbcbcb);
assert((void *)block != (void *)0xfbfbfbfb);
assert((void *)block != (void *)0xdbdbdbdb);
if (block->b_instr != NULL) {
assert(block->b_ialloc > 0);
assert(block->b_iused > 0);
assert(block->b_ialloc >= block->b_iused);
}
else {
assert (block->b_iused == 0);
assert (block->b_ialloc == 0);
}
}
}
static void
compiler_unit_free(struct compiler_unit *u)
{
basicblock *b, *next;
compiler_unit_check(u);
b = u->u_blocks;
while (b != NULL) {
if (b->b_instr)
PyObject_Free((void *)b->b_instr);
next = b->b_list;
PyObject_Free((void *)b);
b = next;
}
Py_CLEAR(u->u_ste);
Py_CLEAR(u->u_name);
Py_CLEAR(u->u_consts);
Py_CLEAR(u->u_names);
Py_CLEAR(u->u_varnames);
Py_CLEAR(u->u_freevars);
Py_CLEAR(u->u_cellvars);
Py_CLEAR(u->u_private);
PyObject_Free(u);
}
static int
compiler_enter_scope(struct compiler *c, identifier name, void *key,
int lineno)
{
struct compiler_unit *u;
u = (struct compiler_unit *)PyObject_Malloc(sizeof(
struct compiler_unit));
if (!u) {
PyErr_NoMemory();
return 0;
}
memset(u, 0, sizeof(struct compiler_unit));
u->u_argcount = 0;
u->u_ste = PySymtable_Lookup(c->c_st, key);
if (!u->u_ste) {
compiler_unit_free(u);
return 0;
}
Py_INCREF(name);
u->u_name = name;
u->u_varnames = list2dict(u->u_ste->ste_varnames);
u->u_cellvars = dictbytype(u->u_ste->ste_symbols, CELL, 0, 0);
if (!u->u_varnames || !u->u_cellvars) {
compiler_unit_free(u);
return 0;
}
u->u_freevars = dictbytype(u->u_ste->ste_symbols, FREE, DEF_FREE_CLASS,
PyDict_Size(u->u_cellvars));
if (!u->u_freevars) {
compiler_unit_free(u);
return 0;
}
u->u_blocks = NULL;
u->u_nfblocks = 0;
u->u_firstlineno = lineno;
u->u_lineno = 0;
u->u_lineno_set = false;
u->u_consts = PyDict_New();
if (!u->u_consts) {
compiler_unit_free(u);
return 0;
}
u->u_names = PyDict_New();
if (!u->u_names) {
compiler_unit_free(u);
return 0;
}
u->u_private = NULL;
/* Push the old compiler_unit on the stack. */
if (c->u) {
PyObject *wrapper = PyCObject_FromVoidPtr(c->u, NULL);
if (!wrapper || PyList_Append(c->c_stack, wrapper) < 0) {
Py_XDECREF(wrapper);
compiler_unit_free(u);
return 0;
}
Py_DECREF(wrapper);
u->u_private = c->u->u_private;
Py_XINCREF(u->u_private);
}
c->u = u;
c->c_nestlevel++;
if (compiler_use_new_block(c) == NULL)
return 0;
return 1;
}
static void
compiler_exit_scope(struct compiler *c)
{
int n;
PyObject *wrapper;
c->c_nestlevel--;
compiler_unit_free(c->u);
/* Restore c->u to the parent unit. */
n = PyList_GET_SIZE(c->c_stack) - 1;
if (n >= 0) {
wrapper = PyList_GET_ITEM(c->c_stack, n);
c->u = (struct compiler_unit *)PyCObject_AsVoidPtr(wrapper);
assert(c->u);
/* we are deleting from a list so this really shouldn't fail */
if (PySequence_DelItem(c->c_stack, n) < 0)
Py_FatalError("compiler_exit_scope()");
compiler_unit_check(c->u);
}
else
c->u = NULL;
}
/* Allocate a new block and return a pointer to it.
Returns NULL on error.
*/
static basicblock *
compiler_new_block(struct compiler *c)
{
basicblock *b;
struct compiler_unit *u;
u = c->u;
b = (basicblock *)PyObject_Malloc(sizeof(basicblock));
if (b == NULL) {
PyErr_NoMemory();
return NULL;
}
memset((void *)b, 0, sizeof(basicblock));
/* Extend the singly linked list of blocks with new block. */
b->b_list = u->u_blocks;
u->u_blocks = b;
return b;
}
static basicblock *
compiler_use_new_block(struct compiler *c)
{
basicblock *block = compiler_new_block(c);
if (block == NULL)
return NULL;
c->u->u_curblock = block;
return block;
}
static basicblock *
compiler_next_block(struct compiler *c)
{
basicblock *block = compiler_new_block(c);
if (block == NULL)
return NULL;
c->u->u_curblock->b_next = block;
c->u->u_curblock = block;
return block;
}
static basicblock *
compiler_use_next_block(struct compiler *c, basicblock *block)
{
assert(block != NULL);
c->u->u_curblock->b_next = block;
c->u->u_curblock = block;
return block;
}
/* Returns the offset of the next instruction in the current block's
b_instr array. Resizes the b_instr as necessary.
Returns -1 on failure.
*/
static int
compiler_next_instr(struct compiler *c, basicblock *b)
{
assert(b != NULL);
if (b->b_instr == NULL) {
b->b_instr = (struct instr *)PyObject_Malloc(
sizeof(struct instr) * DEFAULT_BLOCK_SIZE);
if (b->b_instr == NULL) {
PyErr_NoMemory();
return -1;
}
b->b_ialloc = DEFAULT_BLOCK_SIZE;
memset((char *)b->b_instr, 0,
sizeof(struct instr) * DEFAULT_BLOCK_SIZE);
}
else if (b->b_iused == b->b_ialloc) {
struct instr *tmp;
size_t oldsize, newsize;
oldsize = b->b_ialloc * sizeof(struct instr);
newsize = oldsize << 1;
if (oldsize > (PY_SIZE_MAX >> 1)) {
PyErr_NoMemory();
return -1;
}
if (newsize == 0) {
PyErr_NoMemory();
return -1;
}
b->b_ialloc <<= 1;
tmp = (struct instr *)PyObject_Realloc(
(void *)b->b_instr, newsize);
if (tmp == NULL) {
PyErr_NoMemory();
return -1;
}
b->b_instr = tmp;
memset((char *)b->b_instr + oldsize, 0, newsize - oldsize);
}
return b->b_iused++;
}
/* Set the i_lineno member of the instruction at offset off if the
line number for the current expression/statement has not
already been set. If it has been set, the call has no effect.
The line number is reset in the following cases:
- when entering a new scope
- on each statement
- on each expression that start a new line
- before the "except" clause
- before the "for" and "while" expressions
*/
static void
compiler_set_lineno(struct compiler *c, int off)
{
basicblock *b;
if (c->u->u_lineno_set)
return;
c->u->u_lineno_set = true;
b = c->u->u_curblock;
b->b_instr[off].i_lineno = c->u->u_lineno;
}
static int
opcode_stack_effect(int opcode, int oparg)
{
switch (opcode) {
case POP_TOP:
return -1;
case ROT_TWO:
case ROT_THREE:
return 0;
case DUP_TOP:
return 1;
case ROT_FOUR:
return 0;
case UNARY_POSITIVE:
case UNARY_NEGATIVE:
case UNARY_NOT:
case UNARY_CONVERT:
case UNARY_INVERT:
return 0;
case LIST_APPEND:
return -1;
case BINARY_POWER:
case BINARY_MULTIPLY:
case BINARY_DIVIDE:
case BINARY_MODULO:
case BINARY_ADD:
case BINARY_SUBTRACT:
case BINARY_SUBSCR:
case BINARY_FLOOR_DIVIDE:
case BINARY_TRUE_DIVIDE:
return -1;
case INPLACE_FLOOR_DIVIDE:
case INPLACE_TRUE_DIVIDE:
return -1;
case SLICE+0:
return 1;
case SLICE+1:
return 0;
case SLICE+2:
return 0;
case SLICE+3:
return -1;
case STORE_SLICE+0:
return -2;
case STORE_SLICE+1:
return -3;
case STORE_SLICE+2:
return -3;
case STORE_SLICE+3:
return -4;
case DELETE_SLICE+0:
return -1;
case DELETE_SLICE+1:
return -2;
case DELETE_SLICE+2:
return -2;
case DELETE_SLICE+3:
return -3;
case INPLACE_ADD:
case INPLACE_SUBTRACT:
case INPLACE_MULTIPLY:
case INPLACE_DIVIDE:
case INPLACE_MODULO:
return -1;
case STORE_SUBSCR:
return -3;
case STORE_MAP:
return -2;
case DELETE_SUBSCR:
return -2;
case BINARY_LSHIFT:
case BINARY_RSHIFT:
case BINARY_AND:
case BINARY_XOR:
case BINARY_OR:
return -1;
case INPLACE_POWER:
return -1;
case GET_ITER:
return 0;
case PRINT_EXPR:
return -1;
case PRINT_ITEM:
return -1;
case PRINT_NEWLINE:
return 0;
case PRINT_ITEM_TO:
return -2;
case PRINT_NEWLINE_TO:
return -1;
case INPLACE_LSHIFT:
case INPLACE_RSHIFT:
case INPLACE_AND:
case INPLACE_XOR:
case INPLACE_OR:
return -1;
case BREAK_LOOP:
return 0;
case SETUP_WITH:
return 4;
case WITH_CLEANUP:
return -1; /* XXX Sometimes more */
case LOAD_LOCALS:
return 1;
case RETURN_VALUE:
return -1;
case IMPORT_STAR:
return -1;
case EXEC_STMT:
return -3;
case YIELD_VALUE:
return 0;
case POP_BLOCK:
return 0;
case END_FINALLY:
return -1; /* or -2 or -3 if exception occurred */
case BUILD_CLASS:
return -2;
case STORE_NAME:
return -1;
case DELETE_NAME:
return 0;
case UNPACK_SEQUENCE:
return oparg-1;
case FOR_ITER:
return 1;
case STORE_ATTR:
return -2;
case DELETE_ATTR:
return -1;
case STORE_GLOBAL:
return -1;
case DELETE_GLOBAL:
return 0;
case DUP_TOPX:
return oparg;
case LOAD_CONST:
return 1;
case LOAD_NAME:
return 1;
case BUILD_TUPLE:
case BUILD_LIST:
return 1-oparg;
case BUILD_MAP:
return 1;
case LOAD_ATTR:
return 0;
case COMPARE_OP:
return -1;
case IMPORT_NAME:
return 0;
case IMPORT_FROM:
return 1;
case JUMP_FORWARD:
case JUMP_IF_TRUE_OR_POP: /* -1 if jump not taken */
case JUMP_IF_FALSE_OR_POP: /* "" */
case JUMP_ABSOLUTE:
return 0;
case POP_JUMP_IF_FALSE:
case POP_JUMP_IF_TRUE:
return -1;
case LOAD_GLOBAL:
return 1;
case CONTINUE_LOOP:
return 0;
case SETUP_LOOP:
return 0;
case SETUP_EXCEPT:
case SETUP_FINALLY:
return 3; /* actually pushed by an exception */
case LOAD_FAST:
return 1;
case STORE_FAST:
return -1;
case DELETE_FAST:
return 0;
case RAISE_VARARGS:
return -oparg;
#define NARGS(o) (((o) % 256) + 2*((o) / 256))
case CALL_FUNCTION:
return -NARGS(oparg);
case CALL_FUNCTION_VAR:
case CALL_FUNCTION_KW:
return -NARGS(oparg)-1;
case CALL_FUNCTION_VAR_KW:
return -NARGS(oparg)-2;
#undef NARGS
case MAKE_FUNCTION:
return -oparg;
case BUILD_SLICE:
if (oparg == 3)
return -2;
else
return -1;
case MAKE_CLOSURE:
return -oparg;
case LOAD_CLOSURE:
return 1;
case LOAD_DEREF:
return 1;
case STORE_DEREF:
return -1;
default:
fprintf(stderr, "opcode = %d\n", opcode);
Py_FatalError("opcode_stack_effect()");
}
return 0; /* not reachable */
}
/* Add an opcode with no argument.
Returns 0 on failure, 1 on success.
*/
static int
compiler_addop(struct compiler *c, int opcode)
{
basicblock *b;
struct instr *i;
int off;
off = compiler_next_instr(c, c->u->u_curblock);
if (off < 0)
return 0;
b = c->u->u_curblock;
i = &b->b_instr[off];
i->i_opcode = opcode;
i->i_hasarg = 0;
if (opcode == RETURN_VALUE)
b->b_return = 1;
compiler_set_lineno(c, off);
return 1;
}
static int
compiler_add_o(struct compiler *c, PyObject *dict, PyObject *o)
{
PyObject *t, *v;
Py_ssize_t arg;
unsigned char *p, *q;
Py_complex z;
double d;
int real_part_zero, imag_part_zero;
/* necessary to make sure types aren't coerced (e.g., int and long) */
/* _and_ to distinguish 0.0 from -0.0 e.g. on IEEE platforms */
if (PyFloat_Check(o)) {
d = PyFloat_AS_DOUBLE(o);
p = (unsigned char*) &d;
/* all we need is to make the tuple different in either the 0.0
* or -0.0 case from all others, just to avoid the "coercion".
*/
if (*p==0 && p[sizeof(double)-1]==0)
t = PyTuple_Pack(3, o, o->ob_type, Py_None);
else
t = PyTuple_Pack(2, o, o->ob_type);
}
else if (PyComplex_Check(o)) {
/* complex case is even messier: we need to make complex(x,
0.) different from complex(x, -0.) and complex(0., y)
different from complex(-0., y), for any x and y. In
particular, all four complex zeros should be
distinguished.*/
z = PyComplex_AsCComplex(o);
p = (unsigned char*) &(z.real);
q = (unsigned char*) &(z.imag);
/* all that matters here is that on IEEE platforms
real_part_zero will be true if z.real == 0., and false if
z.real == -0. In fact, real_part_zero will also be true
for some other rarely occurring nonzero floats, but this
doesn't matter. Similar comments apply to
imag_part_zero. */
real_part_zero = *p==0 && p[sizeof(double)-1]==0;
imag_part_zero = *q==0 && q[sizeof(double)-1]==0;
if (real_part_zero && imag_part_zero) {
t = PyTuple_Pack(4, o, o->ob_type, Py_True, Py_True);
}
else if (real_part_zero && !imag_part_zero) {
t = PyTuple_Pack(4, o, o->ob_type, Py_True, Py_False);
}
else if (!real_part_zero && imag_part_zero) {
t = PyTuple_Pack(4, o, o->ob_type, Py_False, Py_True);
}
else {
t = PyTuple_Pack(2, o, o->ob_type);
}
}
else {
t = PyTuple_Pack(2, o, o->ob_type);
}
if (t == NULL)
return -1;
v = PyDict_GetItem(dict, t);
if (!v) {
arg = PyDict_Size(dict);
v = PyInt_FromLong(arg);
if (!v) {
Py_DECREF(t);
return -1;
}
if (PyDict_SetItem(dict, t, v) < 0) {
Py_DECREF(t);
Py_DECREF(v);
return -1;
}
Py_DECREF(v);
}
else
arg = PyInt_AsLong(v);
Py_DECREF(t);
return arg;
}
static int
compiler_addop_o(struct compiler *c, int opcode, PyObject *dict,
PyObject *o)
{
int arg = compiler_add_o(c, dict, o);
if (arg < 0)
return 0;
return compiler_addop_i(c, opcode, arg);
}
static int
compiler_addop_name(struct compiler *c, int opcode, PyObject *dict,
PyObject *o)
{
int arg;
PyObject *mangled = _Py_Mangle(c->u->u_private, o);
if (!mangled)
return 0;
arg = compiler_add_o(c, dict, mangled);
Py_DECREF(mangled);
if (arg < 0)
return 0;
return compiler_addop_i(c, opcode, arg);
}
/* Add an opcode with an integer argument.
Returns 0 on failure, 1 on success.
*/
static int
compiler_addop_i(struct compiler *c, int opcode, int oparg)
{
struct instr *i;
int off;
off = compiler_next_instr(c, c->u->u_curblock);
if (off < 0)
return 0;
i = &c->u->u_curblock->b_instr[off];
i->i_opcode = opcode;
i->i_oparg = oparg;
i->i_hasarg = 1;
compiler_set_lineno(c, off);
return 1;
}
static int
compiler_addop_j(struct compiler *c, int opcode, basicblock *b, int absolute)
{
struct instr *i;
int off;
assert(b != NULL);
off = compiler_next_instr(c, c->u->u_curblock);
if (off < 0)
return 0;
i = &c->u->u_curblock->b_instr[off];
i->i_opcode = opcode;
i->i_target = b;
i->i_hasarg = 1;
if (absolute)
i->i_jabs = 1;
else
i->i_jrel = 1;
compiler_set_lineno(c, off);
return 1;
}
/* The distinction between NEW_BLOCK and NEXT_BLOCK is subtle. (I'd
like to find better names.) NEW_BLOCK() creates a new block and sets
it as the current block. NEXT_BLOCK() also creates an implicit jump
from the current block to the new block.
*/
/* The returns inside these macros make it impossible to decref objects
created in the local function. Local objects should use the arena.
*/
#define NEW_BLOCK(C) { \
if (compiler_use_new_block((C)) == NULL) \
return 0; \
}
#define NEXT_BLOCK(C) { \
if (compiler_next_block((C)) == NULL) \
return 0; \
}
#define ADDOP(C, OP) { \
if (!compiler_addop((C), (OP))) \
return 0; \
}
#define ADDOP_IN_SCOPE(C, OP) { \
if (!compiler_addop((C), (OP))) { \
compiler_exit_scope(c); \
return 0; \
} \
}
#define ADDOP_O(C, OP, O, TYPE) { \
if (!compiler_addop_o((C), (OP), (C)->u->u_ ## TYPE, (O))) \
return 0; \
}
#define ADDOP_NAME(C, OP, O, TYPE) { \
if (!compiler_addop_name((C), (OP), (C)->u->u_ ## TYPE, (O))) \
return 0; \
}
#define ADDOP_I(C, OP, O) { \
if (!compiler_addop_i((C), (OP), (O))) \
return 0; \
}
#define ADDOP_JABS(C, OP, O) { \
if (!compiler_addop_j((C), (OP), (O), 1)) \
return 0; \
}
#define ADDOP_JREL(C, OP, O) { \
if (!compiler_addop_j((C), (OP), (O), 0)) \
return 0; \
}
/* VISIT and VISIT_SEQ takes an ASDL type as their second argument. They use
the ASDL name to synthesize the name of the C type and the visit function.
*/
#define VISIT(C, TYPE, V) {\
if (!compiler_visit_ ## TYPE((C), (V))) \
return 0; \
}
#define VISIT_IN_SCOPE(C, TYPE, V) {\
if (!compiler_visit_ ## TYPE((C), (V))) { \
compiler_exit_scope(c); \
return 0; \
} \
}
#define VISIT_SLICE(C, V, CTX) {\
if (!compiler_visit_slice((C), (V), (CTX))) \
return 0; \
}
#define VISIT_SEQ(C, TYPE, SEQ) { \
int _i; \
asdl_seq *seq = (SEQ); /* avoid variable capture */ \
for (_i = 0; _i < asdl_seq_LEN(seq); _i++) { \
TYPE ## _ty elt = (TYPE ## _ty)asdl_seq_GET(seq, _i); \
if (!compiler_visit_ ## TYPE((C), elt)) \
return 0; \
} \
}
#define VISIT_SEQ_IN_SCOPE(C, TYPE, SEQ) { \
int _i; \
asdl_seq *seq = (SEQ); /* avoid variable capture */ \
for (_i = 0; _i < asdl_seq_LEN(seq); _i++) { \
TYPE ## _ty elt = (TYPE ## _ty)asdl_seq_GET(seq, _i); \
if (!compiler_visit_ ## TYPE((C), elt)) { \
compiler_exit_scope(c); \
return 0; \
} \
} \
}
static int
compiler_isdocstring(stmt_ty s)
{
if (s->kind != Expr_kind)
return 0;
return s->v.Expr.value->kind == Str_kind;
}
/* Compile a sequence of statements, checking for a docstring. */
static int
compiler_body(struct compiler *c, asdl_seq *stmts)
{
int i = 0;
stmt_ty st;
if (!asdl_seq_LEN(stmts))
return 1;
st = (stmt_ty)asdl_seq_GET(stmts, 0);
if (compiler_isdocstring(st) && Py_OptimizeFlag < 2) {
/* don't generate docstrings if -OO */
i = 1;
VISIT(c, expr, st->v.Expr.value);
if (!compiler_nameop(c, __doc__, Store))
return 0;
}
for (; i < asdl_seq_LEN(stmts); i++)
VISIT(c, stmt, (stmt_ty)asdl_seq_GET(stmts, i));
return 1;
}
static PyCodeObject *
compiler_mod(struct compiler *c, mod_ty mod)
{
PyCodeObject *co;
int addNone = 1;
static PyObject *module;
if (!module) {
module = PyString_InternFromString("<module>");
if (!module)
return NULL;
}
/* Use 0 for firstlineno initially, will fixup in assemble(). */
if (!compiler_enter_scope(c, module, mod, 0))
return NULL;
switch (mod->kind) {
case Module_kind:
if (!compiler_body(c, mod->v.Module.body)) {
compiler_exit_scope(c);
return 0;
}
break;
case Interactive_kind:
c->c_interactive = 1;
VISIT_SEQ_IN_SCOPE(c, stmt,
mod->v.Interactive.body);
break;
case Expression_kind:
VISIT_IN_SCOPE(c, expr, mod->v.Expression.body);
addNone = 0;
break;
case Suite_kind:
PyErr_SetString(PyExc_SystemError,
"suite should not be possible");
return 0;
default:
PyErr_Format(PyExc_SystemError,
"module kind %d should not be possible",
mod->kind);
return 0;
}
co = assemble(c, addNone);
compiler_exit_scope(c);
return co;
}
/* The test for LOCAL must come before the test for FREE in order to
handle classes where name is both local and free. The local var is
a method and the free var is a free var referenced within a method.
*/
static int
get_ref_type(struct compiler *c, PyObject *name)
{
int scope = PyST_GetScope(c->u->u_ste, name);
if (scope == 0) {
char buf[350];
PyOS_snprintf(buf, sizeof(buf),
"unknown scope for %.100s in %.100s(%s) in %s\n"
"symbols: %s\nlocals: %s\nglobals: %s",
PyString_AS_STRING(name),
PyString_AS_STRING(c->u->u_name),
PyObject_REPR(c->u->u_ste->ste_id),
c->c_filename,
PyObject_REPR(c->u->u_ste->ste_symbols),
PyObject_REPR(c->u->u_varnames),
PyObject_REPR(c->u->u_names)
);
Py_FatalError(buf);
}
return scope;
}
static int
compiler_lookup_arg(PyObject *dict, PyObject *name)
{
PyObject *k, *v;
k = PyTuple_Pack(2, name, name->ob_type);
if (k == NULL)
return -1;
v = PyDict_GetItem(dict, k);
Py_DECREF(k);
if (v == NULL)
return -1;
return PyInt_AS_LONG(v);
}
static int
compiler_make_closure(struct compiler *c, PyCodeObject *co, int args)
{
int i, free = PyCode_GetNumFree(co);
if (free == 0) {
ADDOP_O(c, LOAD_CONST, (PyObject*)co, consts);
ADDOP_I(c, MAKE_FUNCTION, args);
return 1;
}
for (i = 0; i < free; ++i) {
/* Bypass com_addop_varname because it will generate
LOAD_DEREF but LOAD_CLOSURE is needed.
*/
PyObject *name = PyTuple_GET_ITEM(co->co_freevars, i);
int arg, reftype;
/* Special case: If a class contains a method with a
free variable that has the same name as a method,
the name will be considered free *and* local in the
class. It should be handled by the closure, as
well as by the normal name loookup logic.
*/
reftype = get_ref_type(c, name);
if (reftype == CELL)
arg = compiler_lookup_arg(c->u->u_cellvars, name);
else /* (reftype == FREE) */
arg = compiler_lookup_arg(c->u->u_freevars, name);
if (arg == -1) {
printf("lookup %s in %s %d %d\n"
"freevars of %s: %s\n",
PyObject_REPR(name),
PyString_AS_STRING(c->u->u_name),
reftype, arg,
PyString_AS_STRING(co->co_name),
PyObject_REPR(co->co_freevars));
Py_FatalError("compiler_make_closure()");
}
ADDOP_I(c, LOAD_CLOSURE, arg);
}
ADDOP_I(c, BUILD_TUPLE, free);
ADDOP_O(c, LOAD_CONST, (PyObject*)co, consts);
ADDOP_I(c, MAKE_CLOSURE, args);
return 1;
}
static int
compiler_decorators(struct compiler *c, asdl_seq* decos)
{
int i;
if (!decos)
return 1;
for (i = 0; i < asdl_seq_LEN(decos); i++) {
VISIT(c, expr, (expr_ty)asdl_seq_GET(decos, i));
}
return 1;
}
static int
compiler_arguments(struct compiler *c, arguments_ty args)
{
int i;
int n = asdl_seq_LEN(args->args);
/* Correctly handle nested argument lists */
for (i = 0; i < n; i++) {
expr_ty arg = (expr_ty)asdl_seq_GET(args->args, i);
if (arg->kind == Tuple_kind) {
PyObject *id = PyString_FromFormat(".%d", i);
if (id == NULL) {
return 0;
}
if (!compiler_nameop(c, id, Load)) {
Py_DECREF(id);
return 0;
}
Py_DECREF(id);
VISIT(c, expr, arg);
}
}
return 1;
}
static int
compiler_function(struct compiler *c, stmt_ty s)
{
PyCodeObject *co;
PyObject *first_const = Py_None;
arguments_ty args = s->v.FunctionDef.args;
asdl_seq* decos = s->v.FunctionDef.decorator_list;
stmt_ty st;
int i, n, docstring;
assert(s->kind == FunctionDef_kind);
if (!compiler_decorators(c, decos))
return 0;
if (args->defaults)
VISIT_SEQ(c, expr, args->defaults);
if (!compiler_enter_scope(c, s->v.FunctionDef.name, (void *)s,
s->lineno))
return 0;
st = (stmt_ty)asdl_seq_GET(s->v.FunctionDef.body, 0);
docstring = compiler_isdocstring(st);
if (docstring && Py_OptimizeFlag < 2)
first_const = st->v.Expr.value->v.Str.s;
if (compiler_add_o(c, c->u->u_consts, first_const) < 0) {
compiler_exit_scope(c);
return 0;
}
/* unpack nested arguments */
compiler_arguments(c, args);
c->u->u_argcount = asdl_seq_LEN(args->args);
n = asdl_seq_LEN(s->v.FunctionDef.body);
/* if there was a docstring, we need to skip the first statement */
for (i = docstring; i < n; i++) {
st = (stmt_ty)asdl_seq_GET(s->v.FunctionDef.body, i);
VISIT_IN_SCOPE(c, stmt, st);
}
co = assemble(c, 1);
compiler_exit_scope(c);
if (co == NULL)
return 0;
compiler_make_closure(c, co, asdl_seq_LEN(args->defaults));
Py_DECREF(co);
for (i = 0; i < asdl_seq_LEN(decos); i++) {
ADDOP_I(c, CALL_FUNCTION, 1);
}
return compiler_nameop(c, s->v.FunctionDef.name, Store);
}
static int
compiler_class(struct compiler *c, stmt_ty s)
{
int n, i;
PyCodeObject *co;
PyObject *str;
asdl_seq* decos = s->v.ClassDef.decorator_list;
if (!compiler_decorators(c, decos))
return 0;
/* push class name on stack, needed by BUILD_CLASS */
ADDOP_O(c, LOAD_CONST, s->v.ClassDef.name, consts);
/* push the tuple of base classes on the stack */
n = asdl_seq_LEN(s->v.ClassDef.bases);
if (n > 0)
VISIT_SEQ(c, expr, s->v.ClassDef.bases);
ADDOP_I(c, BUILD_TUPLE, n);
if (!compiler_enter_scope(c, s->v.ClassDef.name, (void *)s,
s->lineno))
return 0;
Py_XDECREF(c->u->u_private);
c->u->u_private = s->v.ClassDef.name;
Py_INCREF(c->u->u_private);
str = PyString_InternFromString("__name__");
if (!str || !compiler_nameop(c, str, Load)) {
Py_XDECREF(str);
compiler_exit_scope(c);
return 0;
}
Py_DECREF(str);
str = PyString_InternFromString("__module__");
if (!str || !compiler_nameop(c, str, Store)) {
Py_XDECREF(str);
compiler_exit_scope(c);
return 0;
}
Py_DECREF(str);
if (!compiler_body(c, s->v.ClassDef.body)) {
compiler_exit_scope(c);
return 0;
}
ADDOP_IN_SCOPE(c, LOAD_LOCALS);
ADDOP_IN_SCOPE(c, RETURN_VALUE);
co = assemble(c, 1);
compiler_exit_scope(c);
if (co == NULL)
return 0;
compiler_make_closure(c, co, 0);
Py_DECREF(co);
ADDOP_I(c, CALL_FUNCTION, 0);
ADDOP(c, BUILD_CLASS);
/* apply decorators */
for (i = 0; i < asdl_seq_LEN(decos); i++) {
ADDOP_I(c, CALL_FUNCTION, 1);
}
if (!compiler_nameop(c, s->v.ClassDef.name, Store))
return 0;
return 1;
}
static int
compiler_ifexp(struct compiler *c, expr_ty e)
{
basicblock *end, *next;
assert(e->kind == IfExp_kind);
end = compiler_new_block(c);
if (end == NULL)
return 0;
next = compiler_new_block(c);
if (next == NULL)
return 0;
VISIT(c, expr, e->v.IfExp.test);
ADDOP_JABS(c, POP_JUMP_IF_FALSE, next);
VISIT(c, expr, e->v.IfExp.body);
ADDOP_JREL(c, JUMP_FORWARD, end);
compiler_use_next_block(c, next);
VISIT(c, expr, e->v.IfExp.orelse);
compiler_use_next_block(c, end);
return 1;
}
static int
compiler_lambda(struct compiler *c, expr_ty e)
{
PyCodeObject *co;
static identifier name;
arguments_ty args = e->v.Lambda.args;
assert(e->kind == Lambda_kind);
if (!name) {
name = PyString_InternFromString("<lambda>");
if (!name)
return 0;
}
if (args->defaults)
VISIT_SEQ(c, expr, args->defaults);
if (!compiler_enter_scope(c, name, (void *)e, e->lineno))
return 0;
/* unpack nested arguments */
compiler_arguments(c, args);
c->u->u_argcount = asdl_seq_LEN(args->args);
VISIT_IN_SCOPE(c, expr, e->v.Lambda.body);
if (c->u->u_ste->ste_generator) {
ADDOP_IN_SCOPE(c, POP_TOP);
}
else {
ADDOP_IN_SCOPE(c, RETURN_VALUE);
}
co = assemble(c, 1);
compiler_exit_scope(c);
if (co == NULL)
return 0;
compiler_make_closure(c, co, asdl_seq_LEN(args->defaults));
Py_DECREF(co);
return 1;
}
static int
compiler_print(struct compiler *c, stmt_ty s)
{
int i, n;
bool dest;
assert(s->kind == Print_kind);
n = asdl_seq_LEN(s->v.Print.values);
dest = false;
if (s->v.Print.dest) {
VISIT(c, expr, s->v.Print.dest);
dest = true;
}
for (i = 0; i < n; i++) {
expr_ty e = (expr_ty)asdl_seq_GET(s->v.Print.values, i);
if (dest) {
ADDOP(c, DUP_TOP);
VISIT(c, expr, e);
ADDOP(c, ROT_TWO);
ADDOP(c, PRINT_ITEM_TO);
}
else {
VISIT(c, expr, e);
ADDOP(c, PRINT_ITEM);
}
}
if (s->v.Print.nl) {
if (dest)
ADDOP(c, PRINT_NEWLINE_TO)
else
ADDOP(c, PRINT_NEWLINE)
}
else if (dest)
ADDOP(c, POP_TOP);
return 1;
}
static int
compiler_if(struct compiler *c, stmt_ty s)
{
basicblock *end, *next;
int constant;
assert(s->kind == If_kind);
end = compiler_new_block(c);
if (end == NULL)
return 0;
constant = expr_constant(s->v.If.test);
/* constant = 0: "if 0"
* constant = 1: "if 1", "if 2", ...
* constant = -1: rest */
if (constant == 0) {
if (s->v.If.orelse)
VISIT_SEQ(c, stmt, s->v.If.orelse);
} else if (constant == 1) {
VISIT_SEQ(c, stmt, s->v.If.body);
} else {
if (s->v.If.orelse) {
next = compiler_new_block(c);
if (next == NULL)
return 0;
}
else
next = end;
VISIT(c, expr, s->v.If.test);
ADDOP_JABS(c, POP_JUMP_IF_FALSE, next);
VISIT_SEQ(c, stmt, s->v.If.body);
ADDOP_JREL(c, JUMP_FORWARD, end);
if (s->v.If.orelse) {
compiler_use_next_block(c, next);
VISIT_SEQ(c, stmt, s->v.If.orelse);
}
}
compiler_use_next_block(c, end);
return 1;
}
static int
compiler_for(struct compiler *c, stmt_ty s)
{
basicblock *start, *cleanup, *end;
start = compiler_new_block(c);
cleanup = compiler_new_block(c);
end = compiler_new_block(c);
if (start == NULL || end == NULL || cleanup == NULL)
return 0;
ADDOP_JREL(c, SETUP_LOOP, end);
if (!compiler_push_fblock(c, LOOP, start))
return 0;
VISIT(c, expr, s->v.For.iter);
ADDOP(c, GET_ITER);
compiler_use_next_block(c, start);
ADDOP_JREL(c, FOR_ITER, cleanup);
VISIT(c, expr, s->v.For.target);
VISIT_SEQ(c, stmt, s->v.For.body);
ADDOP_JABS(c, JUMP_ABSOLUTE, start);
compiler_use_next_block(c, cleanup);
ADDOP(c, POP_BLOCK);
compiler_pop_fblock(c, LOOP, start);
VISIT_SEQ(c, stmt, s->v.For.orelse);
compiler_use_next_block(c, end);
return 1;
}
static int
compiler_while(struct compiler *c, stmt_ty s)
{
basicblock *loop, *orelse, *end, *anchor = NULL;
int constant = expr_constant(s->v.While.test);
if (constant == 0) {
if (s->v.While.orelse)
VISIT_SEQ(c, stmt, s->v.While.orelse);
return 1;
}
loop = compiler_new_block(c);
end = compiler_new_block(c);
if (constant == -1) {
anchor = compiler_new_block(c);
if (anchor == NULL)
return 0;
}
if (loop == NULL || end == NULL)
return 0;
if (s->v.While.orelse) {
orelse = compiler_new_block(c);
if (orelse == NULL)
return 0;
}
else
orelse = NULL;
ADDOP_JREL(c, SETUP_LOOP, end);
compiler_use_next_block(c, loop);
if (!compiler_push_fblock(c, LOOP, loop))
return 0;
if (constant == -1) {
VISIT(c, expr, s->v.While.test);
ADDOP_JABS(c, POP_JUMP_IF_FALSE, anchor);
}
VISIT_SEQ(c, stmt, s->v.While.body);
ADDOP_JABS(c, JUMP_ABSOLUTE, loop);
/* XXX should the two POP instructions be in a separate block
if there is no else clause ?
*/
if (constant == -1) {
compiler_use_next_block(c, anchor);
ADDOP(c, POP_BLOCK);
}
compiler_pop_fblock(c, LOOP, loop);
if (orelse != NULL) /* what if orelse is just pass? */
VISIT_SEQ(c, stmt, s->v.While.orelse);
compiler_use_next_block(c, end);
return 1;
}
static int
compiler_continue(struct compiler *c)
{
static const char LOOP_ERROR_MSG[] = "'continue' not properly in loop";
static const char IN_FINALLY_ERROR_MSG[] =
"'continue' not supported inside 'finally' clause";
int i;
if (!c->u->u_nfblocks)
return compiler_error(c, LOOP_ERROR_MSG);
i = c->u->u_nfblocks - 1;
switch (c->u->u_fblock[i].fb_type) {
case LOOP:
ADDOP_JABS(c, JUMP_ABSOLUTE, c->u->u_fblock[i].fb_block);
break;
case EXCEPT:
case FINALLY_TRY:
while (--i >= 0 && c->u->u_fblock[i].fb_type != LOOP) {
/* Prevent continue anywhere under a finally
even if hidden in a sub-try or except. */
if (c->u->u_fblock[i].fb_type == FINALLY_END)
return compiler_error(c, IN_FINALLY_ERROR_MSG);
}
if (i == -1)
return compiler_error(c, LOOP_ERROR_MSG);
ADDOP_JABS(c, CONTINUE_LOOP, c->u->u_fblock[i].fb_block);
break;
case FINALLY_END:
return compiler_error(c, IN_FINALLY_ERROR_MSG);
}
return 1;
}
/* Code generated for "try: <body> finally: <finalbody>" is as follows:
SETUP_FINALLY L
<code for body>
POP_BLOCK
LOAD_CONST <None>
L: <code for finalbody>
END_FINALLY
The special instructions use the block stack. Each block
stack entry contains the instruction that created it (here
SETUP_FINALLY), the level of the value stack at the time the
block stack entry was created, and a label (here L).
SETUP_FINALLY:
Pushes the current value stack level and the label
onto the block stack.
POP_BLOCK:
Pops en entry from the block stack, and pops the value
stack until its level is the same as indicated on the
block stack. (The label is ignored.)
END_FINALLY:
Pops a variable number of entries from the *value* stack
and re-raises the exception they specify. The number of
entries popped depends on the (pseudo) exception type.
The block stack is unwound when an exception is raised:
when a SETUP_FINALLY entry is found, the exception is pushed
onto the value stack (and the exception condition is cleared),
and the interpreter jumps to the label gotten from the block
stack.
*/
static int
compiler_try_finally(struct compiler *c, stmt_ty s)
{
basicblock *body, *end;
body = compiler_new_block(c);
end = compiler_new_block(c);
if (body == NULL || end == NULL)
return 0;
ADDOP_JREL(c, SETUP_FINALLY, end);
compiler_use_next_block(c, body);
if (!compiler_push_fblock(c, FINALLY_TRY, body))
return 0;
VISIT_SEQ(c, stmt, s->v.TryFinally.body);
ADDOP(c, POP_BLOCK);
compiler_pop_fblock(c, FINALLY_TRY, body);
ADDOP_O(c, LOAD_CONST, Py_None, consts);
compiler_use_next_block(c, end);
if (!compiler_push_fblock(c, FINALLY_END, end))
return 0;
VISIT_SEQ(c, stmt, s->v.TryFinally.finalbody);
ADDOP(c, END_FINALLY);
compiler_pop_fblock(c, FINALLY_END, end);
return 1;
}
/*
Code generated for "try: S except E1, V1: S1 except E2, V2: S2 ...":
(The contents of the value stack is shown in [], with the top
at the right; 'tb' is trace-back info, 'val' the exception's
associated value, and 'exc' the exception.)
Value stack Label Instruction Argument
[] SETUP_EXCEPT L1
[] <code for S>
[] POP_BLOCK
[] JUMP_FORWARD L0
[tb, val, exc] L1: DUP )
[tb, val, exc, exc] <evaluate E1> )
[tb, val, exc, exc, E1] COMPARE_OP EXC_MATCH ) only if E1
[tb, val, exc, 1-or-0] POP_JUMP_IF_FALSE L2 )
[tb, val, exc] POP
[tb, val] <assign to V1> (or POP if no V1)
[tb] POP
[] <code for S1>
JUMP_FORWARD L0
[tb, val, exc] L2: DUP
.............................etc.......................
[tb, val, exc] Ln+1: END_FINALLY # re-raise exception
[] L0: <next statement>
Of course, parts are not generated if Vi or Ei is not present.
*/
static int
compiler_try_except(struct compiler *c, stmt_ty s)
{
basicblock *body, *orelse, *except, *end;
int i, n;
body = compiler_new_block(c);
except = compiler_new_block(c);
orelse = compiler_new_block(c);
end = compiler_new_block(c);
if (body == NULL || except == NULL || orelse == NULL || end == NULL)
return 0;
ADDOP_JREL(c, SETUP_EXCEPT, except);
compiler_use_next_block(c, body);
if (!compiler_push_fblock(c, EXCEPT, body))
return 0;
VISIT_SEQ(c, stmt, s->v.TryExcept.body);
ADDOP(c, POP_BLOCK);
compiler_pop_fblock(c, EXCEPT, body);
ADDOP_JREL(c, JUMP_FORWARD, orelse);
n = asdl_seq_LEN(s->v.TryExcept.handlers);
compiler_use_next_block(c, except);
for (i = 0; i < n; i++) {
excepthandler_ty handler = (excepthandler_ty)asdl_seq_GET(
s->v.TryExcept.handlers, i);
if (!handler->v.ExceptHandler.type && i < n-1)
return compiler_error(c, "default 'except:' must be last");
c->u->u_lineno_set = false;
c->u->u_lineno = handler->lineno;
except = compiler_new_block(c);
if (except == NULL)
return 0;
if (handler->v.ExceptHandler.type) {
ADDOP(c, DUP_TOP);
VISIT(c, expr, handler->v.ExceptHandler.type);
ADDOP_I(c, COMPARE_OP, PyCmp_EXC_MATCH);
ADDOP_JABS(c, POP_JUMP_IF_FALSE, except);
}
ADDOP(c, POP_TOP);
if (handler->v.ExceptHandler.name) {
VISIT(c, expr, handler->v.ExceptHandler.name);
}
else {
ADDOP(c, POP_TOP);
}
ADDOP(c, POP_TOP);
VISIT_SEQ(c, stmt, handler->v.ExceptHandler.body);
ADDOP_JREL(c, JUMP_FORWARD, end);
compiler_use_next_block(c, except);
}
ADDOP(c, END_FINALLY);
compiler_use_next_block(c, orelse);
VISIT_SEQ(c, stmt, s->v.TryExcept.orelse);
compiler_use_next_block(c, end);
return 1;
}
static int
compiler_import_as(struct compiler *c, identifier name, identifier asname)
{
/* The IMPORT_NAME opcode was already generated. This function
merely needs to bind the result to a name.
If there is a dot in name, we need to split it and emit a
LOAD_ATTR for each name.
*/
const char *src = PyString_AS_STRING(name);
const char *dot = strchr(src, '.');
if (dot) {
/* Consume the base module name to get the first attribute */
src = dot + 1;
while (dot) {
/* NB src is only defined when dot != NULL */
PyObject *attr;
dot = strchr(src, '.');
attr = PyString_FromStringAndSize(src,
dot ? dot - src : strlen(src));
if (!attr)
return -1;
ADDOP_O(c, LOAD_ATTR, attr, names);
Py_DECREF(attr);
src = dot + 1;
}
}
return compiler_nameop(c, asname, Store);
}
static int
compiler_import(struct compiler *c, stmt_ty s)
{
/* The Import node stores a module name like a.b.c as a single
string. This is convenient for all cases except
import a.b.c as d
where we need to parse that string to extract the individual
module names.
XXX Perhaps change the representation to make this case simpler?
*/
int i, n = asdl_seq_LEN(s->v.Import.names);
for (i = 0; i < n; i++) {
alias_ty alias = (alias_ty)asdl_seq_GET(s->v.Import.names, i);
int r;
PyObject *level;
if (c->c_flags && (c->c_flags->cf_flags & CO_FUTURE_ABSOLUTE_IMPORT))
level = PyInt_FromLong(0);
else
level = PyInt_FromLong(-1);
if (level == NULL)
return 0;
ADDOP_O(c, LOAD_CONST, level, consts);
Py_DECREF(level);
ADDOP_O(c, LOAD_CONST, Py_None, consts);
ADDOP_NAME(c, IMPORT_NAME, alias->name, names);
if (alias->asname) {
r = compiler_import_as(c, alias->name, alias->asname);
if (!r)
return r;
}
else {
identifier tmp = alias->name;
const char *base = PyString_AS_STRING(alias->name);
char *dot = strchr(base, '.');
if (dot)
tmp = PyString_FromStringAndSize(base,
dot - base);
r = compiler_nameop(c, tmp, Store);
if (dot) {
Py_DECREF(tmp);
}
if (!r)
return r;
}
}
return 1;
}
static int
compiler_from_import(struct compiler *c, stmt_ty s)
{
int i, n = asdl_seq_LEN(s->v.ImportFrom.names);
PyObject *names = PyTuple_New(n);
PyObject *level;
static PyObject *empty_string;
if (!empty_string) {
empty_string = PyString_FromString("");
if (!empty_string)
return 0;
}
if (!names)
return 0;
if (s->v.ImportFrom.level == 0 && c->c_flags &&
!(c->c_flags->cf_flags & CO_FUTURE_ABSOLUTE_IMPORT))
level = PyInt_FromLong(-1);
else
level = PyInt_FromLong(s->v.ImportFrom.level);
if (!level) {
Py_DECREF(names);
return 0;
}
/* build up the names */
for (i = 0; i < n; i++) {
alias_ty alias = (alias_ty)asdl_seq_GET(s->v.ImportFrom.names, i);
Py_INCREF(alias->name);
PyTuple_SET_ITEM(names, i, alias->name);
}
if (s->lineno > c->c_future->ff_lineno && s->v.ImportFrom.module &&
!strcmp(PyString_AS_STRING(s->v.ImportFrom.module), "__future__")) {
Py_DECREF(level);
Py_DECREF(names);
return compiler_error(c, "from __future__ imports must occur "
"at the beginning of the file");
}
ADDOP_O(c, LOAD_CONST, level, consts);
Py_DECREF(level);
ADDOP_O(c, LOAD_CONST, names, consts);
Py_DECREF(names);
if (s->v.ImportFrom.module) {
ADDOP_NAME(c, IMPORT_NAME, s->v.ImportFrom.module, names);
}
else {
ADDOP_NAME(c, IMPORT_NAME, empty_string, names);
}
for (i = 0; i < n; i++) {
alias_ty alias = (alias_ty)asdl_seq_GET(s->v.ImportFrom.names, i);
identifier store_name;
if (i == 0 && *PyString_AS_STRING(alias->name) == '*') {
assert(n == 1);
ADDOP(c, IMPORT_STAR);
return 1;
}
ADDOP_NAME(c, IMPORT_FROM, alias->name, names);
store_name = alias->name;
if (alias->asname)
store_name = alias->asname;
if (!compiler_nameop(c, store_name, Store)) {
Py_DECREF(names);
return 0;
}
}
/* remove imported module */
ADDOP(c, POP_TOP);
return 1;
}
static int
compiler_assert(struct compiler *c, stmt_ty s)
{
static PyObject *assertion_error = NULL;
basicblock *end;
if (Py_OptimizeFlag)
return 1;
if (assertion_error == NULL) {
assertion_error = PyString_InternFromString("AssertionError");
if (assertion_error == NULL)
return 0;
}
if (s->v.Assert.test->kind == Tuple_kind &&
asdl_seq_LEN(s->v.Assert.test->v.Tuple.elts) > 0) {
const char* msg =
"assertion is always true, perhaps remove parentheses?";
if (PyErr_WarnExplicit(PyExc_SyntaxWarning, msg, c->c_filename,
c->u->u_lineno, NULL, NULL) == -1)
return 0;
}
VISIT(c, expr, s->v.Assert.test);
end = compiler_new_block(c);
if (end == NULL)
return 0;
ADDOP_JABS(c, POP_JUMP_IF_TRUE, end);
ADDOP_O(c, LOAD_GLOBAL, assertion_error, names);
if (s->v.Assert.msg) {
VISIT(c, expr, s->v.Assert.msg);
ADDOP_I(c, RAISE_VARARGS, 2);
}
else {
ADDOP_I(c, RAISE_VARARGS, 1);
}
compiler_use_next_block(c, end);
return 1;
}
static int
compiler_visit_stmt(struct compiler *c, stmt_ty s)
{
int i, n;
/* Always assign a lineno to the next instruction for a stmt. */
c->u->u_lineno = s->lineno;
c->u->u_lineno_set = false;
switch (s->kind) {
case FunctionDef_kind:
return compiler_function(c, s);
case ClassDef_kind:
return compiler_class(c, s);
case Return_kind:
if (c->u->u_ste->ste_type != FunctionBlock)
return compiler_error(c, "'return' outside function");
if (s->v.Return.value) {
VISIT(c, expr, s->v.Return.value);
}
else
ADDOP_O(c, LOAD_CONST, Py_None, consts);
ADDOP(c, RETURN_VALUE);
break;
case Delete_kind:
VISIT_SEQ(c, expr, s->v.Delete.targets)
break;
case Assign_kind:
n = asdl_seq_LEN(s->v.Assign.targets);
VISIT(c, expr, s->v.Assign.value);
for (i = 0; i < n; i++) {
if (i < n - 1)
ADDOP(c, DUP_TOP);
VISIT(c, expr,
(expr_ty)asdl_seq_GET(s->v.Assign.targets, i));
}
break;
case AugAssign_kind:
return compiler_augassign(c, s);
case Print_kind:
return compiler_print(c, s);
case For_kind:
return compiler_for(c, s);
case While_kind:
return compiler_while(c, s);
case If_kind:
return compiler_if(c, s);
case Raise_kind:
n = 0;
if (s->v.Raise.type) {
VISIT(c, expr, s->v.Raise.type);
n++;
if (s->v.Raise.inst) {
VISIT(c, expr, s->v.Raise.inst);
n++;
if (s->v.Raise.tback) {
VISIT(c, expr, s->v.Raise.tback);
n++;
}
}
}
ADDOP_I(c, RAISE_VARARGS, n);
break;
case TryExcept_kind:
return compiler_try_except(c, s);
case TryFinally_kind:
return compiler_try_finally(c, s);
case Assert_kind:
return compiler_assert(c, s);
case Import_kind:
return compiler_import(c, s);
case ImportFrom_kind:
return compiler_from_import(c, s);
case Exec_kind:
VISIT(c, expr, s->v.Exec.body);
if (s->v.Exec.globals) {
VISIT(c, expr, s->v.Exec.globals);
if (s->v.Exec.locals) {
VISIT(c, expr, s->v.Exec.locals);
} else {
ADDOP(c, DUP_TOP);
}
} else {
ADDOP_O(c, LOAD_CONST, Py_None, consts);
ADDOP(c, DUP_TOP);
}
ADDOP(c, EXEC_STMT);
break;
case Global_kind:
break;
case Expr_kind:
if (c->c_interactive && c->c_nestlevel <= 1) {
VISIT(c, expr, s->v.Expr.value);
ADDOP(c, PRINT_EXPR);
}
else if (s->v.Expr.value->kind != Str_kind &&
s->v.Expr.value->kind != Num_kind) {
VISIT(c, expr, s->v.Expr.value);
ADDOP(c, POP_TOP);
}
break;
case Pass_kind:
break;
case Break_kind:
if (!compiler_in_loop(c))
return compiler_error(c, "'break' outside loop");
ADDOP(c, BREAK_LOOP);
break;
case Continue_kind:
return compiler_continue(c);
case With_kind:
return compiler_with(c, s);
}
return 1;
}
static int
unaryop(unaryop_ty op)
{
switch (op) {
case Invert:
return UNARY_INVERT;
case Not:
return UNARY_NOT;
case UAdd:
return UNARY_POSITIVE;
case USub:
return UNARY_NEGATIVE;
default:
PyErr_Format(PyExc_SystemError,
"unary op %d should not be possible", op);
return 0;
}
}
static int
binop(struct compiler *c, operator_ty op)
{
switch (op) {
case Add:
return BINARY_ADD;
case Sub:
return BINARY_SUBTRACT;
case Mult:
return BINARY_MULTIPLY;
case Div:
if (c->c_flags && c->c_flags->cf_flags & CO_FUTURE_DIVISION)
return BINARY_TRUE_DIVIDE;
else
return BINARY_DIVIDE;
case Mod:
return BINARY_MODULO;
case Pow:
return BINARY_POWER;
case LShift:
return BINARY_LSHIFT;
case RShift:
return BINARY_RSHIFT;
case BitOr:
return BINARY_OR;
case BitXor:
return BINARY_XOR;
case BitAnd:
return BINARY_AND;
case FloorDiv:
return BINARY_FLOOR_DIVIDE;
default:
PyErr_Format(PyExc_SystemError,
"binary op %d should not be possible", op);
return 0;
}
}
static int
cmpop(cmpop_ty op)
{
switch (op) {
case Eq:
return PyCmp_EQ;
case NotEq:
return PyCmp_NE;
case Lt:
return PyCmp_LT;
case LtE:
return PyCmp_LE;
case Gt:
return PyCmp_GT;
case GtE:
return PyCmp_GE;
case Is:
return PyCmp_IS;
case IsNot:
return PyCmp_IS_NOT;
case In:
return PyCmp_IN;
case NotIn:
return PyCmp_NOT_IN;
default:
return PyCmp_BAD;
}
}
static int
inplace_binop(struct compiler *c, operator_ty op)
{
switch (op) {
case Add:
return INPLACE_ADD;
case Sub:
return INPLACE_SUBTRACT;
case Mult:
return INPLACE_MULTIPLY;
case Div:
if (c->c_flags && c->c_flags->cf_flags & CO_FUTURE_DIVISION)
return INPLACE_TRUE_DIVIDE;
else
return INPLACE_DIVIDE;
case Mod:
return INPLACE_MODULO;
case Pow:
return INPLACE_POWER;
case LShift:
return INPLACE_LSHIFT;
case RShift:
return INPLACE_RSHIFT;
case BitOr:
return INPLACE_OR;
case BitXor:
return INPLACE_XOR;
case BitAnd:
return INPLACE_AND;
case FloorDiv:
return INPLACE_FLOOR_DIVIDE;
default:
PyErr_Format(PyExc_SystemError,
"inplace binary op %d should not be possible", op);
return 0;
}
}
static int
compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx)
{
int op, scope, arg;
enum { OP_FAST, OP_GLOBAL, OP_DEREF, OP_NAME } optype;
PyObject *dict = c->u->u_names;
PyObject *mangled;
/* XXX AugStore isn't used anywhere! */
mangled = _Py_Mangle(c->u->u_private, name);
if (!mangled)
return 0;
op = 0;
optype = OP_NAME;
scope = PyST_GetScope(c->u->u_ste, mangled);
switch (scope) {
case FREE:
dict = c->u->u_freevars;
optype = OP_DEREF;
break;
case CELL:
dict = c->u->u_cellvars;
optype = OP_DEREF;
break;
case LOCAL:
if (c->u->u_ste->ste_type == FunctionBlock)
optype = OP_FAST;
break;
case GLOBAL_IMPLICIT:
if (c->u->u_ste->ste_type == FunctionBlock &&
!c->u->u_ste->ste_unoptimized)
optype = OP_GLOBAL;
break;
case GLOBAL_EXPLICIT:
optype = OP_GLOBAL;
break;
default:
/* scope can be 0 */
break;
}
/* XXX Leave assert here, but handle __doc__ and the like better */
assert(scope || PyString_AS_STRING(name)[0] == '_');
switch (optype) {
case OP_DEREF:
switch (ctx) {
case Load: op = LOAD_DEREF; break;
case Store: op = STORE_DEREF; break;
case AugLoad:
case AugStore:
break;
case Del:
PyErr_Format(PyExc_SyntaxError,
"can not delete variable '%s' referenced "
"in nested scope",
PyString_AS_STRING(name));
Py_DECREF(mangled);
return 0;
case Param:
default:
PyErr_SetString(PyExc_SystemError,
"param invalid for deref variable");
return 0;
}
break;
case OP_FAST:
switch (ctx) {
case Load: op = LOAD_FAST; break;
case Store: op = STORE_FAST; break;
case Del: op = DELETE_FAST; break;
case AugLoad:
case AugStore:
break;
case Param:
default:
PyErr_SetString(PyExc_SystemError,
"param invalid for local variable");
return 0;
}
ADDOP_O(c, op, mangled, varnames);
Py_DECREF(mangled);
return 1;
case OP_GLOBAL:
switch (ctx) {
case Load: op = LOAD_GLOBAL; break;
case Store: op = STORE_GLOBAL; break;
case Del: op = DELETE_GLOBAL; break;
case AugLoad:
case AugStore:
break;
case Param:
default:
PyErr_SetString(PyExc_SystemError,
"param invalid for global variable");
return 0;
}
break;
case OP_NAME:
switch (ctx) {
case Load: op = LOAD_NAME; break;
case Store: op = STORE_NAME; break;
case Del: op = DELETE_NAME; break;
case AugLoad:
case AugStore:
break;
case Param:
default:
PyErr_SetString(PyExc_SystemError,
"param invalid for name variable");
return 0;
}
break;
}
assert(op);
arg = compiler_add_o(c, dict, mangled);
Py_DECREF(mangled);
if (arg < 0)
return 0;
return compiler_addop_i(c, op, arg);
}
static int
compiler_boolop(struct compiler *c, expr_ty e)
{
basicblock *end;
int jumpi, i, n;
asdl_seq *s;
assert(e->kind == BoolOp_kind);
if (e->v.BoolOp.op == And)
jumpi = JUMP_IF_FALSE_OR_POP;
else
jumpi = JUMP_IF_TRUE_OR_POP;
end = compiler_new_block(c);
if (end == NULL)
return 0;
s = e->v.BoolOp.values;
n = asdl_seq_LEN(s) - 1;
assert(n >= 0);
for (i = 0; i < n; ++i) {
VISIT(c, expr, (expr_ty)asdl_seq_GET(s, i));
ADDOP_JABS(c, jumpi, end);
}
VISIT(c, expr, (expr_ty)asdl_seq_GET(s, n));
compiler_use_next_block(c, end);
return 1;
}
static int
compiler_list(struct compiler *c, expr_ty e)
{
int n = asdl_seq_LEN(e->v.List.elts);
if (e->v.List.ctx == Store) {
ADDOP_I(c, UNPACK_SEQUENCE, n);
}
VISIT_SEQ(c, expr, e->v.List.elts);
if (e->v.List.ctx == Load) {
ADDOP_I(c, BUILD_LIST, n);
}
return 1;
}
static int
compiler_tuple(struct compiler *c, expr_ty e)
{
int n = asdl_seq_LEN(e->v.Tuple.elts);
if (e->v.Tuple.ctx == Store) {
ADDOP_I(c, UNPACK_SEQUENCE, n);
}
VISIT_SEQ(c, expr, e->v.Tuple.elts);
if (e->v.Tuple.ctx == Load) {
ADDOP_I(c, BUILD_TUPLE, n);
}
return 1;
}
static int
compiler_compare(struct compiler *c, expr_ty e)
{
int i, n;
basicblock *cleanup = NULL;
/* XXX the logic can be cleaned up for 1 or multiple comparisons */
VISIT(c, expr, e->v.Compare.left);
n = asdl_seq_LEN(e->v.Compare.ops);
assert(n > 0);
if (n > 1) {
cleanup = compiler_new_block(c);
if (cleanup == NULL)
return 0;
VISIT(c, expr,
(expr_ty)asdl_seq_GET(e->v.Compare.comparators, 0));
}
for (i = 1; i < n; i++) {
ADDOP(c, DUP_TOP);
ADDOP(c, ROT_THREE);
ADDOP_I(c, COMPARE_OP,
cmpop((cmpop_ty)(asdl_seq_GET(
e->v.Compare.ops, i - 1))));
ADDOP_JABS(c, JUMP_IF_FALSE_OR_POP, cleanup);
NEXT_BLOCK(c);
if (i < (n - 1))
VISIT(c, expr,
(expr_ty)asdl_seq_GET(e->v.Compare.comparators, i));
}
VISIT(c, expr, (expr_ty)asdl_seq_GET(e->v.Compare.comparators, n - 1));
ADDOP_I(c, COMPARE_OP,
cmpop((cmpop_ty)(asdl_seq_GET(e->v.Compare.ops, n - 1))));
if (n > 1) {
basicblock *end = compiler_new_block(c);
if (end == NULL)
return 0;
ADDOP_JREL(c, JUMP_FORWARD, end);
compiler_use_next_block(c, cleanup);
ADDOP(c, ROT_TWO);
ADDOP(c, POP_TOP);
compiler_use_next_block(c, end);
}
return 1;
}
static int
compiler_call(struct compiler *c, expr_ty e)
{
int n, code = 0;
VISIT(c, expr, e->v.Call.func);
n = asdl_seq_LEN(e->v.Call.args);
VISIT_SEQ(c, expr, e->v.Call.args);
if (e->v.Call.keywords) {
VISIT_SEQ(c, keyword, e->v.Call.keywords);
n |= asdl_seq_LEN(e->v.Call.keywords) << 8;
}
if (e->v.Call.starargs) {
VISIT(c, expr, e->v.Call.starargs);
code |= 1;
}
if (e->v.Call.kwargs) {
VISIT(c, expr, e->v.Call.kwargs);
code |= 2;
}
switch (code) {
case 0:
ADDOP_I(c, CALL_FUNCTION, n);
break;
case 1:
ADDOP_I(c, CALL_FUNCTION_VAR, n);
break;
case 2:
ADDOP_I(c, CALL_FUNCTION_KW, n);
break;
case 3:
ADDOP_I(c, CALL_FUNCTION_VAR_KW, n);
break;
}
return 1;
}
static int
compiler_listcomp_generator(struct compiler *c, asdl_seq *generators,
int gen_index, expr_ty elt)
{
/* generate code for the iterator, then each of the ifs,
and then write to the element */
comprehension_ty l;
basicblock *start, *anchor, *skip, *if_cleanup;
int i, n;
start = compiler_new_block(c);
skip = compiler_new_block(c);
if_cleanup = compiler_new_block(c);
anchor = compiler_new_block(c);
if (start == NULL || skip == NULL || if_cleanup == NULL ||
anchor == NULL)
return 0;
l = (comprehension_ty)asdl_seq_GET(generators, gen_index);
VISIT(c, expr, l->iter);
ADDOP(c, GET_ITER);
compiler_use_next_block(c, start);
ADDOP_JREL(c, FOR_ITER, anchor);
NEXT_BLOCK(c);
VISIT(c, expr, l->target);
/* XXX this needs to be cleaned up...a lot! */
n = asdl_seq_LEN(l->ifs);
for (i = 0; i < n; i++) {
expr_ty e = (expr_ty)asdl_seq_GET(l->ifs, i);
VISIT(c, expr, e);
ADDOP_JABS(c, POP_JUMP_IF_FALSE, if_cleanup);
NEXT_BLOCK(c);
}
if (++gen_index < asdl_seq_LEN(generators))
if (!compiler_listcomp_generator(c, generators, gen_index, elt))
return 0;
/* only append after the last for generator */
if (gen_index >= asdl_seq_LEN(generators)) {
VISIT(c, expr, elt);
ADDOP_I(c, LIST_APPEND, gen_index+1);
compiler_use_next_block(c, skip);
}
compiler_use_next_block(c, if_cleanup);
ADDOP_JABS(c, JUMP_ABSOLUTE, start);
compiler_use_next_block(c, anchor);
return 1;
}
static int
compiler_listcomp(struct compiler *c, expr_ty e)
{
assert(e->kind == ListComp_kind);
ADDOP_I(c, BUILD_LIST, 0);
return compiler_listcomp_generator(c, e->v.ListComp.generators, 0,
e->v.ListComp.elt);
}
static int
compiler_genexp_generator(struct compiler *c,
asdl_seq *generators, int gen_index,
expr_ty elt)
{
/* generate code for the iterator, then each of the ifs,
and then write to the element */
comprehension_ty ge;
basicblock *start, *anchor, *skip, *if_cleanup, *end;
int i, n;
start = compiler_new_block(c);
skip = compiler_new_block(c);
if_cleanup = compiler_new_block(c);
anchor = compiler_new_block(c);
end = compiler_new_block(c);
if (start == NULL || skip == NULL || if_cleanup == NULL ||
anchor == NULL || end == NULL)
return 0;
ge = (comprehension_ty)asdl_seq_GET(generators, gen_index);
ADDOP_JREL(c, SETUP_LOOP, end);
if (!compiler_push_fblock(c, LOOP, start))
return 0;
if (gen_index == 0) {
/* Receive outermost iter as an implicit argument */
c->u->u_argcount = 1;
ADDOP_I(c, LOAD_FAST, 0);
}
else {
/* Sub-iter - calculate on the fly */
VISIT(c, expr, ge->iter);
ADDOP(c, GET_ITER);
}
compiler_use_next_block(c, start);
ADDOP_JREL(c, FOR_ITER, anchor);
NEXT_BLOCK(c);
VISIT(c, expr, ge->target);
/* XXX this needs to be cleaned up...a lot! */
n = asdl_seq_LEN(ge->ifs);
for (i = 0; i < n; i++) {
expr_ty e = (expr_ty)asdl_seq_GET(ge->ifs, i);
VISIT(c, expr, e);
ADDOP_JABS(c, POP_JUMP_IF_FALSE, if_cleanup);
NEXT_BLOCK(c);
}
if (++gen_index < asdl_seq_LEN(generators))
if (!compiler_genexp_generator(c, generators, gen_index, elt))
return 0;
/* only append after the last 'for' generator */
if (gen_index >= asdl_seq_LEN(generators)) {
VISIT(c, expr, elt);
ADDOP(c, YIELD_VALUE);
ADDOP(c, POP_TOP);
compiler_use_next_block(c, skip);
}
compiler_use_next_block(c, if_cleanup);
ADDOP_JABS(c, JUMP_ABSOLUTE, start);
compiler_use_next_block(c, anchor);
ADDOP(c, POP_BLOCK);
compiler_pop_fblock(c, LOOP, start);
compiler_use_next_block(c, end);
return 1;
}
static int
compiler_genexp(struct compiler *c, expr_ty e)
{
static identifier name;
PyCodeObject *co;
expr_ty outermost_iter = ((comprehension_ty)
(asdl_seq_GET(e->v.GeneratorExp.generators,
0)))->iter;
if (!name) {
name = PyString_FromString("<genexpr>");
if (!name)
return 0;
}
if (!compiler_enter_scope(c, name, (void *)e, e->lineno))
return 0;
compiler_genexp_generator(c, e->v.GeneratorExp.generators, 0,
e->v.GeneratorExp.elt);
co = assemble(c, 1);
compiler_exit_scope(c);
if (co == NULL)
return 0;
compiler_make_closure(c, co, 0);
Py_DECREF(co);
VISIT(c, expr, outermost_iter);
ADDOP(c, GET_ITER);
ADDOP_I(c, CALL_FUNCTION, 1);
return 1;
}
static int
compiler_visit_keyword(struct compiler *c, keyword_ty k)
{
ADDOP_O(c, LOAD_CONST, k->arg, consts);
VISIT(c, expr, k->value);
return 1;
}
/* Test whether expression is constant. For constants, report
whether they are true or false.
Return values: 1 for true, 0 for false, -1 for non-constant.
*/
static int
expr_constant(expr_ty e)
{
switch (e->kind) {
case Num_kind:
return PyObject_IsTrue(e->v.Num.n);
case Str_kind:
return PyObject_IsTrue(e->v.Str.s);
case Name_kind:
/* __debug__ is not assignable, so we can optimize
* it away in if and while statements */
if (strcmp(PyString_AS_STRING(e->v.Name.id),
"__debug__") == 0)
return ! Py_OptimizeFlag;
/* fall through */
default:
return -1;
}
}
/*
Implements the with statement from PEP 343.
The semantics outlined in that PEP are as follows:
with EXPR as VAR:
BLOCK
It is implemented roughly as:
context = EXPR
exit = context.__exit__ # not calling it
value = context.__enter__()
try:
VAR = value # if VAR present in the syntax
BLOCK
finally:
if an exception was raised:
exc = copy of (exception, instance, traceback)
else:
exc = (None, None, None)
exit(*exc)
*/
static int
compiler_with(struct compiler *c, stmt_ty s)
{
basicblock *block, *finally;
assert(s->kind == With_kind);
block = compiler_new_block(c);
finally = compiler_new_block(c);
if (!block || !finally)
return 0;
/* Evaluate EXPR */
VISIT(c, expr, s->v.With.context_expr);
ADDOP_JREL(c, SETUP_WITH, finally);
/* SETUP_WITH pushes a finally block. */
compiler_use_next_block(c, block);
if (!compiler_push_fblock(c, FINALLY_TRY, block)) {
return 0;
}
if (s->v.With.optional_vars) {
VISIT(c, expr, s->v.With.optional_vars);
}
else {
/* Discard result from context.__enter__() */
ADDOP(c, POP_TOP);
}
/* BLOCK code */
VISIT_SEQ(c, stmt, s->v.With.body);
/* End of try block; start the finally block */
ADDOP(c, POP_BLOCK);
compiler_pop_fblock(c, FINALLY_TRY, block);
ADDOP_O(c, LOAD_CONST, Py_None, consts);
compiler_use_next_block(c, finally);
if (!compiler_push_fblock(c, FINALLY_END, finally))
return 0;
/* Finally block starts; context.__exit__ is on the stack under
the exception or return information. Just issue our magic
opcode. */
ADDOP(c, WITH_CLEANUP);
/* Finally block ends. */
ADDOP(c, END_FINALLY);
compiler_pop_fblock(c, FINALLY_END, finally);
return 1;
}
static int
compiler_visit_expr(struct compiler *c, expr_ty e)
{
int i, n;
/* If expr e has a different line number than the last expr/stmt,
set a new line number for the next instruction.
*/
if (e->lineno > c->u->u_lineno) {
c->u->u_lineno = e->lineno;
c->u->u_lineno_set = false;
}
switch (e->kind) {
case BoolOp_kind:
return compiler_boolop(c, e);
case BinOp_kind:
VISIT(c, expr, e->v.BinOp.left);
VISIT(c, expr, e->v.BinOp.right);
ADDOP(c, binop(c, e->v.BinOp.op));
break;
case UnaryOp_kind:
VISIT(c, expr, e->v.UnaryOp.operand);
ADDOP(c, unaryop(e->v.UnaryOp.op));
break;
case Lambda_kind:
return compiler_lambda(c, e);
case IfExp_kind:
return compiler_ifexp(c, e);
case Dict_kind:
n = asdl_seq_LEN(e->v.Dict.values);
ADDOP_I(c, BUILD_MAP, (n>0xFFFF ? 0xFFFF : n));
for (i = 0; i < n; i++) {
VISIT(c, expr,
(expr_ty)asdl_seq_GET(e->v.Dict.values, i));
VISIT(c, expr,
(expr_ty)asdl_seq_GET(e->v.Dict.keys, i));
ADDOP(c, STORE_MAP);
}
break;
case ListComp_kind:
return compiler_listcomp(c, e);
case GeneratorExp_kind:
return compiler_genexp(c, e);
case Yield_kind:
if (c->u->u_ste->ste_type != FunctionBlock)
return compiler_error(c, "'yield' outside function");
if (e->v.Yield.value) {
VISIT(c, expr, e->v.Yield.value);
}
else {
ADDOP_O(c, LOAD_CONST, Py_None, consts);
}
ADDOP(c, YIELD_VALUE);
break;
case Compare_kind:
return compiler_compare(c, e);
case Call_kind:
return compiler_call(c, e);
case Repr_kind:
VISIT(c, expr, e->v.Repr.value);
ADDOP(c, UNARY_CONVERT);
break;
case Num_kind:
ADDOP_O(c, LOAD_CONST, e->v.Num.n, consts);
break;
case Str_kind:
ADDOP_O(c, LOAD_CONST, e->v.Str.s, consts);
break;
/* The following exprs can be assignment targets. */
case Attribute_kind:
if (e->v.Attribute.ctx != AugStore)
VISIT(c, expr, e->v.Attribute.value);
switch (e->v.Attribute.ctx) {
case AugLoad:
ADDOP(c, DUP_TOP);
/* Fall through to load */
case Load:
ADDOP_NAME(c, LOAD_ATTR, e->v.Attribute.attr, names);
break;
case AugStore:
ADDOP(c, ROT_TWO);
/* Fall through to save */
case Store:
ADDOP_NAME(c, STORE_ATTR, e->v.Attribute.attr, names);
break;
case Del:
ADDOP_NAME(c, DELETE_ATTR, e->v.Attribute.attr, names);
break;
case Param:
default:
PyErr_SetString(PyExc_SystemError,
"param invalid in attribute expression");
return 0;
}
break;
case Subscript_kind:
switch (e->v.Subscript.ctx) {
case AugLoad:
VISIT(c, expr, e->v.Subscript.value);
VISIT_SLICE(c, e->v.Subscript.slice, AugLoad);
break;
case Load:
VISIT(c, expr, e->v.Subscript.value);
VISIT_SLICE(c, e->v.Subscript.slice, Load);
break;
case AugStore:
VISIT_SLICE(c, e->v.Subscript.slice, AugStore);
break;
case Store:
VISIT(c, expr, e->v.Subscript.value);
VISIT_SLICE(c, e->v.Subscript.slice, Store);
break;
case Del:
VISIT(c, expr, e->v.Subscript.value);
VISIT_SLICE(c, e->v.Subscript.slice, Del);
break;
case Param:
default:
PyErr_SetString(PyExc_SystemError,
"param invalid in subscript expression");
return 0;
}
break;
case Name_kind:
return compiler_nameop(c, e->v.Name.id, e->v.Name.ctx);
/* child nodes of List and Tuple will have expr_context set */
case List_kind:
return compiler_list(c, e);
case Tuple_kind:
return compiler_tuple(c, e);
}
return 1;
}
static int
compiler_augassign(struct compiler *c, stmt_ty s)
{
expr_ty e = s->v.AugAssign.target;
expr_ty auge;
assert(s->kind == AugAssign_kind);
switch (e->kind) {
case Attribute_kind:
auge = Attribute(e->v.Attribute.value, e->v.Attribute.attr,
AugLoad, e->lineno, e->col_offset, c->c_arena);
if (auge == NULL)
return 0;
VISIT(c, expr, auge);
VISIT(c, expr, s->v.AugAssign.value);
ADDOP(c, inplace_binop(c, s->v.AugAssign.op));
auge->v.Attribute.ctx = AugStore;
VISIT(c, expr, auge);
break;
case Subscript_kind:
auge = Subscript(e->v.Subscript.value, e->v.Subscript.slice,
AugLoad, e->lineno, e->col_offset, c->c_arena);
if (auge == NULL)
return 0;
VISIT(c, expr, auge);
VISIT(c, expr, s->v.AugAssign.value);
ADDOP(c, inplace_binop(c, s->v.AugAssign.op));
auge->v.Subscript.ctx = AugStore;
VISIT(c, expr, auge);
break;
case Name_kind:
if (!compiler_nameop(c, e->v.Name.id, Load))
return 0;
VISIT(c, expr, s->v.AugAssign.value);
ADDOP(c, inplace_binop(c, s->v.AugAssign.op));
return compiler_nameop(c, e->v.Name.id, Store);
default:
PyErr_Format(PyExc_SystemError,
"invalid node type (%d) for augmented assignment",
e->kind);
return 0;
}
return 1;
}
static int
compiler_push_fblock(struct compiler *c, enum fblocktype t, basicblock *b)
{
struct fblockinfo *f;
if (c->u->u_nfblocks >= CO_MAXBLOCKS) {
PyErr_SetString(PyExc_SystemError,
"too many statically nested blocks");
return 0;
}
f = &c->u->u_fblock[c->u->u_nfblocks++];
f->fb_type = t;
f->fb_block = b;
return 1;
}
static void
compiler_pop_fblock(struct compiler *c, enum fblocktype t, basicblock *b)
{
struct compiler_unit *u = c->u;
assert(u->u_nfblocks > 0);
u->u_nfblocks--;
assert(u->u_fblock[u->u_nfblocks].fb_type == t);
assert(u->u_fblock[u->u_nfblocks].fb_block == b);
}
static int
compiler_in_loop(struct compiler *c) {
int i;
struct compiler_unit *u = c->u;
for (i = 0; i < u->u_nfblocks; ++i) {
if (u->u_fblock[i].fb_type == LOOP)
return 1;
}
return 0;
}
/* Raises a SyntaxError and returns 0.
If something goes wrong, a different exception may be raised.
*/
static int
compiler_error(struct compiler *c, const char *errstr)
{
PyObject *loc;
PyObject *u = NULL, *v = NULL;
loc = PyErr_ProgramText(c->c_filename, c->u->u_lineno);
if (!loc) {
Py_INCREF(Py_None);
loc = Py_None;
}
u = Py_BuildValue("(ziOO)", c->c_filename, c->u->u_lineno,
Py_None, loc);
if (!u)
goto exit;
v = Py_BuildValue("(zO)", errstr, u);
if (!v)
goto exit;
PyErr_SetObject(PyExc_SyntaxError, v);
exit:
Py_DECREF(loc);
Py_XDECREF(u);
Py_XDECREF(v);
return 0;
}
static int
compiler_handle_subscr(struct compiler *c, const char *kind,
expr_context_ty ctx)
{
int op = 0;
/* XXX this code is duplicated */
switch (ctx) {
case AugLoad: /* fall through to Load */
case Load: op = BINARY_SUBSCR; break;
case AugStore:/* fall through to Store */
case Store: op = STORE_SUBSCR; break;
case Del: op = DELETE_SUBSCR; break;
case Param:
PyErr_Format(PyExc_SystemError,
"invalid %s kind %d in subscript\n",
kind, ctx);
return 0;
}
if (ctx == AugLoad) {
ADDOP_I(c, DUP_TOPX, 2);
}
else if (ctx == AugStore) {
ADDOP(c, ROT_THREE);
}
ADDOP(c, op);
return 1;
}
static int
compiler_slice(struct compiler *c, slice_ty s, expr_context_ty ctx)
{
int n = 2;
assert(s->kind == Slice_kind);
/* only handles the cases where BUILD_SLICE is emitted */
if (s->v.Slice.lower) {
VISIT(c, expr, s->v.Slice.lower);
}
else {
ADDOP_O(c, LOAD_CONST, Py_None, consts);
}
if (s->v.Slice.upper) {
VISIT(c, expr, s->v.Slice.upper);
}
else {
ADDOP_O(c, LOAD_CONST, Py_None, consts);
}
if (s->v.Slice.step) {
n++;
VISIT(c, expr, s->v.Slice.step);
}
ADDOP_I(c, BUILD_SLICE, n);
return 1;
}
static int
compiler_simple_slice(struct compiler *c, slice_ty s, expr_context_ty ctx)
{
int op = 0, slice_offset = 0, stack_count = 0;
assert(s->v.Slice.step == NULL);
if (s->v.Slice.lower) {
slice_offset++;
stack_count++;
if (ctx != AugStore)
VISIT(c, expr, s->v.Slice.lower);
}
if (s->v.Slice.upper) {
slice_offset += 2;
stack_count++;
if (ctx != AugStore)
VISIT(c, expr, s->v.Slice.upper);
}
if (ctx == AugLoad) {
switch (stack_count) {
case 0: ADDOP(c, DUP_TOP); break;
case 1: ADDOP_I(c, DUP_TOPX, 2); break;
case 2: ADDOP_I(c, DUP_TOPX, 3); break;
}
}
else if (ctx == AugStore) {
switch (stack_count) {
case 0: ADDOP(c, ROT_TWO); break;
case 1: ADDOP(c, ROT_THREE); break;
case 2: ADDOP(c, ROT_FOUR); break;
}
}
switch (ctx) {
case AugLoad: /* fall through to Load */
case Load: op = SLICE; break;
case AugStore:/* fall through to Store */
case Store: op = STORE_SLICE; break;
case Del: op = DELETE_SLICE; break;
case Param:
default:
PyErr_SetString(PyExc_SystemError,
"param invalid in simple slice");
return 0;
}
ADDOP(c, op + slice_offset);
return 1;
}
static int
compiler_visit_nested_slice(struct compiler *c, slice_ty s,
expr_context_ty ctx)
{
switch (s->kind) {
case Ellipsis_kind:
ADDOP_O(c, LOAD_CONST, Py_Ellipsis, consts);
break;
case Slice_kind:
return compiler_slice(c, s, ctx);
case Index_kind:
VISIT(c, expr, s->v.Index.value);
break;
case ExtSlice_kind:
default:
PyErr_SetString(PyExc_SystemError,
"extended slice invalid in nested slice");
return 0;
}
return 1;
}
static int
compiler_visit_slice(struct compiler *c, slice_ty s, expr_context_ty ctx)
{
char * kindname = NULL;
switch (s->kind) {
case Index_kind:
kindname = "index";
if (ctx != AugStore) {
VISIT(c, expr, s->v.Index.value);
}
break;
case Ellipsis_kind:
kindname = "ellipsis";
if (ctx != AugStore) {
ADDOP_O(c, LOAD_CONST, Py_Ellipsis, consts);
}
break;
case Slice_kind:
kindname = "slice";
if (!s->v.Slice.step)
return compiler_simple_slice(c, s, ctx);
if (ctx != AugStore) {
if (!compiler_slice(c, s, ctx))
return 0;
}
break;
case ExtSlice_kind:
kindname = "extended slice";
if (ctx != AugStore) {
int i, n = asdl_seq_LEN(s->v.ExtSlice.dims);
for (i = 0; i < n; i++) {
slice_ty sub = (slice_ty)asdl_seq_GET(
s->v.ExtSlice.dims, i);
if (!compiler_visit_nested_slice(c, sub, ctx))
return 0;
}
ADDOP_I(c, BUILD_TUPLE, n);
}
break;
default:
PyErr_Format(PyExc_SystemError,
"invalid subscript kind %d", s->kind);
return 0;
}
return compiler_handle_subscr(c, kindname, ctx);
}
/* End of the compiler section, beginning of the assembler section */
/* do depth-first search of basic block graph, starting with block.
post records the block indices in post-order.
XXX must handle implicit jumps from one block to next
*/
struct assembler {
PyObject *a_bytecode; /* string containing bytecode */
int a_offset; /* offset into bytecode */
int a_nblocks; /* number of reachable blocks */
basicblock **a_postorder; /* list of blocks in dfs postorder */
PyObject *a_lnotab; /* string containing lnotab */
int a_lnotab_off; /* offset into lnotab */
int a_lineno; /* last lineno of emitted instruction */
int a_lineno_off; /* bytecode offset of last lineno */
};
static void
dfs(struct compiler *c, basicblock *b, struct assembler *a)
{
int i;
struct instr *instr = NULL;
if (b->b_seen)
return;
b->b_seen = 1;
if (b->b_next != NULL)
dfs(c, b->b_next, a);
for (i = 0; i < b->b_iused; i++) {
instr = &b->b_instr[i];
if (instr->i_jrel || instr->i_jabs)
dfs(c, instr->i_target, a);
}
a->a_postorder[a->a_nblocks++] = b;
}
static int
stackdepth_walk(struct compiler *c, basicblock *b, int depth, int maxdepth)
{
int i;
struct instr *instr;
if (b->b_seen || b->b_startdepth >= depth)
return maxdepth;
b->b_seen = 1;
b->b_startdepth = depth;
for (i = 0; i < b->b_iused; i++) {
instr = &b->b_instr[i];
depth += opcode_stack_effect(instr->i_opcode, instr->i_oparg);
if (depth > maxdepth)
maxdepth = depth;
assert(depth >= 0); /* invalid code or bug in stackdepth() */
if (instr->i_jrel || instr->i_jabs) {
maxdepth = stackdepth_walk(c, instr->i_target,
depth, maxdepth);
if (instr->i_opcode == JUMP_ABSOLUTE ||
instr->i_opcode == JUMP_FORWARD) {
goto out; /* remaining code is dead */
}
}
}
if (b->b_next)
maxdepth = stackdepth_walk(c, b->b_next, depth, maxdepth);
out:
b->b_seen = 0;
return maxdepth;
}
/* Find the flow path that needs the largest stack. We assume that
* cycles in the flow graph have no net effect on the stack depth.
*/
static int
stackdepth(struct compiler *c)
{
basicblock *b, *entryblock;
entryblock = NULL;
for (b = c->u->u_blocks; b != NULL; b = b->b_list) {
b->b_seen = 0;
b->b_startdepth = INT_MIN;
entryblock = b;
}
if (!entryblock)
return 0;
return stackdepth_walk(c, entryblock, 0, 0);
}
static int
assemble_init(struct assembler *a, int nblocks, int firstlineno)
{
memset(a, 0, sizeof(struct assembler));
a->a_lineno = firstlineno;
a->a_bytecode = PyString_FromStringAndSize(NULL, DEFAULT_CODE_SIZE);
if (!a->a_bytecode)
return 0;
a->a_lnotab = PyString_FromStringAndSize(NULL, DEFAULT_LNOTAB_SIZE);
if (!a->a_lnotab)
return 0;
if (nblocks > PY_SIZE_MAX / sizeof(basicblock *)) {
PyErr_NoMemory();
return 0;
}
a->a_postorder = (basicblock **)PyObject_Malloc(
sizeof(basicblock *) * nblocks);
if (!a->a_postorder) {
PyErr_NoMemory();
return 0;
}
return 1;
}
static void
assemble_free(struct assembler *a)
{
Py_XDECREF(a->a_bytecode);
Py_XDECREF(a->a_lnotab);
if (a->a_postorder)
PyObject_Free(a->a_postorder);
}
/* Return the size of a basic block in bytes. */
static int
instrsize(struct instr *instr)
{
if (!instr->i_hasarg)
return 1; /* 1 byte for the opcode*/
if (instr->i_oparg > 0xffff)
return 6; /* 1 (opcode) + 1 (EXTENDED_ARG opcode) + 2 (oparg) + 2(oparg extended) */
return 3; /* 1 (opcode) + 2 (oparg) */
}
static int
blocksize(basicblock *b)
{
int i;
int size = 0;
for (i = 0; i < b->b_iused; i++)
size += instrsize(&b->b_instr[i]);
return size;
}
/* Appends a pair to the end of the line number table, a_lnotab, representing
the instruction's bytecode offset and line number. See
Objects/lnotab_notes.txt for the description of the line number table. */
static int
assemble_lnotab(struct assembler *a, struct instr *i)
{
int d_bytecode, d_lineno;
int len;
unsigned char *lnotab;
d_bytecode = a->a_offset - a->a_lineno_off;
d_lineno = i->i_lineno - a->a_lineno;
assert(d_bytecode >= 0);
assert(d_lineno >= 0);
if(d_bytecode == 0 && d_lineno == 0)
return 1;
if (d_bytecode > 255) {
int j, nbytes, ncodes = d_bytecode / 255;
nbytes = a->a_lnotab_off + 2 * ncodes;
len = PyString_GET_SIZE(a->a_lnotab);
if (nbytes >= len) {
if ((len <= INT_MAX / 2) && (len * 2 < nbytes))
len = nbytes;
else if (len <= INT_MAX / 2)
len *= 2;
else {
PyErr_NoMemory();
return 0;
}
if (_PyString_Resize(&a->a_lnotab, len) < 0)
return 0;
}
lnotab = (unsigned char *)
PyString_AS_STRING(a->a_lnotab) + a->a_lnotab_off;
for (j = 0; j < ncodes; j++) {
*lnotab++ = 255;
*lnotab++ = 0;
}
d_bytecode -= ncodes * 255;
a->a_lnotab_off += ncodes * 2;
}
assert(d_bytecode <= 255);
if (d_lineno > 255) {
int j, nbytes, ncodes = d_lineno / 255;
nbytes = a->a_lnotab_off + 2 * ncodes;
len = PyString_GET_SIZE(a->a_lnotab);
if (nbytes >= len) {
if ((len <= INT_MAX / 2) && len * 2 < nbytes)
len = nbytes;
else if (len <= INT_MAX / 2)
len *= 2;
else {
PyErr_NoMemory();
return 0;
}
if (_PyString_Resize(&a->a_lnotab, len) < 0)
return 0;
}
lnotab = (unsigned char *)
PyString_AS_STRING(a->a_lnotab) + a->a_lnotab_off;
*lnotab++ = d_bytecode;
*lnotab++ = 255;
d_bytecode = 0;
for (j = 1; j < ncodes; j++) {
*lnotab++ = 0;
*lnotab++ = 255;
}
d_lineno -= ncodes * 255;
a->a_lnotab_off += ncodes * 2;
}
len = PyString_GET_SIZE(a->a_lnotab);
if (a->a_lnotab_off + 2 >= len) {
if (_PyString_Resize(&a->a_lnotab, len * 2) < 0)
return 0;
}
lnotab = (unsigned char *)
PyString_AS_STRING(a->a_lnotab) + a->a_lnotab_off;
a->a_lnotab_off += 2;
if (d_bytecode) {
*lnotab++ = d_bytecode;
*lnotab++ = d_lineno;
}
else { /* First line of a block; def stmt, etc. */
*lnotab++ = 0;
*lnotab++ = d_lineno;
}
a->a_lineno = i->i_lineno;
a->a_lineno_off = a->a_offset;
return 1;
}
/* assemble_emit()
Extend the bytecode with a new instruction.
Update lnotab if necessary.
*/
static int
assemble_emit(struct assembler *a, struct instr *i)
{
int size, arg = 0, ext = 0;
Py_ssize_t len = PyString_GET_SIZE(a->a_bytecode);
char *code;
size = instrsize(i);
if (i->i_hasarg) {
arg = i->i_oparg;
ext = arg >> 16;
}
if (i->i_lineno && !assemble_lnotab(a, i))
return 0;
if (a->a_offset + size >= len) {
if (len > PY_SSIZE_T_MAX / 2)
return 0;
if (_PyString_Resize(&a->a_bytecode, len * 2) < 0)
return 0;
}
code = PyString_AS_STRING(a->a_bytecode) + a->a_offset;
a->a_offset += size;
if (size == 6) {
assert(i->i_hasarg);
*code++ = (char)EXTENDED_ARG;
*code++ = ext & 0xff;
*code++ = ext >> 8;
arg &= 0xffff;
}
*code++ = i->i_opcode;
if (i->i_hasarg) {
assert(size == 3 || size == 6);
*code++ = arg & 0xff;
*code++ = arg >> 8;
}
return 1;
}
static void
assemble_jump_offsets(struct assembler *a, struct compiler *c)
{
basicblock *b;
int bsize, totsize, extended_arg_count, last_extended_arg_count = 0;
int i;
/* Compute the size of each block and fixup jump args.
Replace block pointer with position in bytecode. */
start:
totsize = 0;
for (i = a->a_nblocks - 1; i >= 0; i--) {
b = a->a_postorder[i];
bsize = blocksize(b);
b->b_offset = totsize;
totsize += bsize;
}
extended_arg_count = 0;
for (b = c->u->u_blocks; b != NULL; b = b->b_list) {
bsize = b->b_offset;
for (i = 0; i < b->b_iused; i++) {
struct instr *instr = &b->b_instr[i];
/* Relative jumps are computed relative to
the instruction pointer after fetching
the jump instruction.
*/
bsize += instrsize(instr);
if (instr->i_jabs)
instr->i_oparg = instr->i_target->b_offset;
else if (instr->i_jrel) {
int delta = instr->i_target->b_offset - bsize;
instr->i_oparg = delta;
}
else
continue;
if (instr->i_oparg > 0xffff)
extended_arg_count++;
}
}
/* XXX: This is an awful hack that could hurt performance, but
on the bright side it should work until we come up
with a better solution.
In the meantime, should the goto be dropped in favor
of a loop?
The issue is that in the first loop blocksize() is called
which calls instrsize() which requires i_oparg be set
appropriately. There is a bootstrap problem because
i_oparg is calculated in the second loop above.
So we loop until we stop seeing new EXTENDED_ARGs.
The only EXTENDED_ARGs that could be popping up are
ones in jump instructions. So this should converge
fairly quickly.
*/
if (last_extended_arg_count != extended_arg_count) {
last_extended_arg_count = extended_arg_count;
goto start;
}
}
static PyObject *
dict_keys_inorder(PyObject *dict, int offset)
{
PyObject *tuple, *k, *v;
Py_ssize_t i, pos = 0, size = PyDict_Size(dict);
tuple = PyTuple_New(size);
if (tuple == NULL)
return NULL;
while (PyDict_Next(dict, &pos, &k, &v)) {
i = PyInt_AS_LONG(v);
/* The keys of the dictionary are tuples. (see compiler_add_o)
The object we want is always first, though. */
k = PyTuple_GET_ITEM(k, 0);
Py_INCREF(k);
assert((i - offset) < size);
assert((i - offset) >= 0);
PyTuple_SET_ITEM(tuple, i - offset, k);
}
return tuple;
}
static int
compute_code_flags(struct compiler *c)
{
PySTEntryObject *ste = c->u->u_ste;
int flags = 0, n;
if (ste->ste_type != ModuleBlock)
flags |= CO_NEWLOCALS;
if (ste->ste_type == FunctionBlock) {
if (!ste->ste_unoptimized)
flags |= CO_OPTIMIZED;
if (ste->ste_nested)
flags |= CO_NESTED;
if (ste->ste_generator)
flags |= CO_GENERATOR;
if (ste->ste_varargs)
flags |= CO_VARARGS;
if (ste->ste_varkeywords)
flags |= CO_VARKEYWORDS;
}
/* (Only) inherit compilerflags in PyCF_MASK */
flags |= (c->c_flags->cf_flags & PyCF_MASK);
n = PyDict_Size(c->u->u_freevars);
if (n < 0)
return -1;
if (n == 0) {
n = PyDict_Size(c->u->u_cellvars);
if (n < 0)
return -1;
if (n == 0) {
flags |= CO_NOFREE;
}
}
return flags;
}
static PyCodeObject *
makecode(struct compiler *c, struct assembler *a)
{
PyObject *tmp;
PyCodeObject *co = NULL;
PyObject *consts = NULL;
PyObject *names = NULL;
PyObject *varnames = NULL;
PyObject *filename = NULL;
PyObject *name = NULL;
PyObject *freevars = NULL;
PyObject *cellvars = NULL;
PyObject *bytecode = NULL;
int nlocals, flags;
tmp = dict_keys_inorder(c->u->u_consts, 0);
if (!tmp)
goto error;
consts = PySequence_List(tmp); /* optimize_code requires a list */
Py_DECREF(tmp);
names = dict_keys_inorder(c->u->u_names, 0);
varnames = dict_keys_inorder(c->u->u_varnames, 0);
if (!consts || !names || !varnames)
goto error;
cellvars = dict_keys_inorder(c->u->u_cellvars, 0);
if (!cellvars)
goto error;
freevars = dict_keys_inorder(c->u->u_freevars, PyTuple_Size(cellvars));
if (!freevars)
goto error;
filename = PyString_FromString(c->c_filename);
if (!filename)
goto error;
nlocals = PyDict_Size(c->u->u_varnames);
flags = compute_code_flags(c);
if (flags < 0)
goto error;
bytecode = PyCode_Optimize(a->a_bytecode, consts, names, a->a_lnotab);
if (!bytecode)
goto error;
tmp = PyList_AsTuple(consts); /* PyCode_New requires a tuple */
if (!tmp)
goto error;
Py_DECREF(consts);
consts = tmp;
co = PyCode_New(c->u->u_argcount, nlocals, stackdepth(c), flags,
bytecode, consts, names, varnames,
freevars, cellvars,
filename, c->u->u_name,
c->u->u_firstlineno,
a->a_lnotab);
error:
Py_XDECREF(consts);
Py_XDECREF(names);
Py_XDECREF(varnames);
Py_XDECREF(filename);
Py_XDECREF(name);
Py_XDECREF(freevars);
Py_XDECREF(cellvars);
Py_XDECREF(bytecode);
return co;
}
/* For debugging purposes only */
#if 0
static void
dump_instr(const struct instr *i)
{
const char *jrel = i->i_jrel ? "jrel " : "";
const char *jabs = i->i_jabs ? "jabs " : "";
char arg[128];
*arg = '\0';
if (i->i_hasarg)
sprintf(arg, "arg: %d ", i->i_oparg);
fprintf(stderr, "line: %d, opcode: %d %s%s%s\n",
i->i_lineno, i->i_opcode, arg, jabs, jrel);
}
static void
dump_basicblock(const basicblock *b)
{
const char *seen = b->b_seen ? "seen " : "";
const char *b_return = b->b_return ? "return " : "";
fprintf(stderr, "used: %d, depth: %d, offset: %d %s%s\n",
b->b_iused, b->b_startdepth, b->b_offset, seen, b_return);
if (b->b_instr) {
int i;
for (i = 0; i < b->b_iused; i++) {
fprintf(stderr, " [%02d] ", i);
dump_instr(b->b_instr + i);
}
}
}
#endif
static PyCodeObject *
assemble(struct compiler *c, int addNone)
{
basicblock *b, *entryblock;
struct assembler a;
int i, j, nblocks;
PyCodeObject *co = NULL;
/* Make sure every block that falls off the end returns None.
XXX NEXT_BLOCK() isn't quite right, because if the last
block ends with a jump or return b_next shouldn't set.
*/
if (!c->u->u_curblock->b_return) {
NEXT_BLOCK(c);
if (addNone)
ADDOP_O(c, LOAD_CONST, Py_None, consts);
ADDOP(c, RETURN_VALUE);
}
nblocks = 0;
entryblock = NULL;
for (b = c->u->u_blocks; b != NULL; b = b->b_list) {
nblocks++;
entryblock = b;
}
/* Set firstlineno if it wasn't explicitly set. */
if (!c->u->u_firstlineno) {
if (entryblock && entryblock->b_instr)
c->u->u_firstlineno = entryblock->b_instr->i_lineno;
else
c->u->u_firstlineno = 1;
}
if (!assemble_init(&a, nblocks, c->u->u_firstlineno))
goto error;
dfs(c, entryblock, &a);
/* Can't modify the bytecode after computing jump offsets. */
assemble_jump_offsets(&a, c);
/* Emit code in reverse postorder from dfs. */
for (i = a.a_nblocks - 1; i >= 0; i--) {
b = a.a_postorder[i];
for (j = 0; j < b->b_iused; j++)
if (!assemble_emit(&a, &b->b_instr[j]))
goto error;
}
if (_PyString_Resize(&a.a_lnotab, a.a_lnotab_off) < 0)
goto error;
if (_PyString_Resize(&a.a_bytecode, a.a_offset) < 0)
goto error;
co = makecode(c, &a);
error:
assemble_free(&a);
return co;
}
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