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Issue #19722: Added opcode.stack_effect(), which accurately

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computes the stack effect of bytecode instructions.
This commit is contained in:
Larry Hastings 2013-11-23 14:49:22 -08:00
parent 8d0d369067
commit 3a9079742f
8 changed files with 177 additions and 8 deletions
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20
Python/compile.c
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@ -853,8 +853,8 @@ compiler_set_lineno(struct compiler *c, int off)
b->b_instr[off].i_lineno = c->u->u_lineno;
}
static int
opcode_stack_effect(int opcode, int oparg)
int
PyCompile_OpcodeStackEffect(int opcode, int oparg)
{
switch (opcode) {
case POP_TOP:
@ -1044,11 +1044,9 @@ opcode_stack_effect(int opcode, int oparg)
case DELETE_DEREF:
return 0;
default:
fprintf(stderr, "opcode = %d\n", opcode);
Py_FatalError("opcode_stack_effect()");
return PY_INVALID_STACK_EFFECT;
}
return 0; /* not reachable */
return PY_INVALID_STACK_EFFECT; /* not reachable */
}
/* Add an opcode with no argument.
@ -3829,7 +3827,7 @@ dfs(struct compiler *c, basicblock *b, struct assembler *a)
static int
stackdepth_walk(struct compiler *c, basicblock *b, int depth, int maxdepth)
{
int i, target_depth;
int i, target_depth, effect;
struct instr *instr;
if (b->b_seen || b->b_startdepth >= depth)
return maxdepth;
@ -3837,7 +3835,13 @@ stackdepth_walk(struct compiler *c, basicblock *b, int depth, int maxdepth)
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);
effect = PyCompile_OpcodeStackEffect(instr->i_opcode, instr->i_oparg);
if (effect == PY_INVALID_STACK_EFFECT) {
fprintf(stderr, "opcode = %d\n", instr->i_opcode);
Py_FatalError("PyCompile_OpcodeStackEffect()");
}
depth += effect;
if (depth > maxdepth)
maxdepth = depth;
assert(depth >= 0); /* invalid code or bug in stackdepth() */