bpo-43760: Check for tracing using 'bitwise or' instead of branch in dispatch. (GH-28723)

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Mark Shannon 2021-10-05 11:01:11 +01:00 committed by GitHub
parent ef6196028f
commit bd627eb7ed
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GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 249 additions and 217 deletions

1
Include/opcode.h generated
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@ -167,6 +167,7 @@ extern "C" {
#define LOAD_FAST__LOAD_CONST 134
#define LOAD_CONST__LOAD_FAST 140
#define STORE_FAST__STORE_FAST 143
#define DO_TRACING 255
#ifdef NEED_OPCODE_JUMP_TABLES
static uint32_t _PyOpcode_RelativeJump[8] = {
0U,

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@ -0,0 +1,3 @@
The number of hardware branches per instruction dispatch is reduced from two
to one by adding a special instruction for tracing. Patch by Mark Shannon.

File diff suppressed because it is too large Load Diff

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@ -32,6 +32,7 @@ def write_contents(f):
"""
opcode = find_module('opcode')
targets = ['_unknown_opcode'] * 256
targets[255] = "TARGET_DO_TRACING"
for opname, op in opcode.opmap.items():
targets[op] = "TARGET_%s" % opname
next_op = 1

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@ -254,5 +254,5 @@ static void *opcode_targets[256] = {
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode,
&&_unknown_opcode
&&TARGET_DO_TRACING
};

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@ -268,7 +268,7 @@ sys_audit_tstate(PyThreadState *ts, const char *event,
break;
}
if (canTrace) {
ts->cframe->use_tracing = (ts->c_tracefunc || ts->c_profilefunc);
ts->cframe->use_tracing = (ts->c_tracefunc || ts->c_profilefunc) ? 255 : 0;
ts->tracing--;
}
PyObject* args[2] = {eventName, eventArgs};
@ -283,7 +283,7 @@ sys_audit_tstate(PyThreadState *ts, const char *event,
Py_DECREF(o);
Py_CLEAR(hook);
}
ts->cframe->use_tracing = (ts->c_tracefunc || ts->c_profilefunc);
ts->cframe->use_tracing = (ts->c_tracefunc || ts->c_profilefunc) ? 255 : 0;
ts->tracing--;
if (_PyErr_Occurred(ts)) {
goto exit;

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@ -72,7 +72,7 @@ def main(opcode_py, outfile='Include/opcode.h'):
next_op += 1
fobj.write("#define %-23s %3s\n" % (name, next_op))
used[next_op] = True
fobj.write("#define DO_TRACING 255\n")
fobj.write("#ifdef NEED_OPCODE_JUMP_TABLES\n")
write_int_array_from_ops("_PyOpcode_RelativeJump", opcode['hasjrel'], fobj)
write_int_array_from_ops("_PyOpcode_Jump", opcode['hasjrel'] + opcode['hasjabs'], fobj)