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authorNeil Schemenauer <nascheme@enme.ucalgary.ca>2009-10-14 19:14:38 (GMT)
committerNeil Schemenauer <nascheme@enme.ucalgary.ca>2009-10-14 19:14:38 (GMT)
commite441cb71c73649da991d8bc418650f2748a58f72 (patch)
treeb66219e97e32365d78713941065d74315d8d026d /Python
parent46afef330f88ddcf4106094e86f54f90dbdec390 (diff)
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Issue #1754094: Improve the stack depth calculation in the compiler.
There should be no other effect than a small decrease in memory use.
Diffstat (limited to 'Python')
-rw-r--r--Python/compile.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/Python/compile.c b/Python/compile.c
index 24975b6..d06a03b 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -772,7 +772,7 @@ opcode_stack_effect(int opcode, int oparg)
case UNPACK_EX:
return (oparg&0xFF) + (oparg>>8);
case FOR_ITER:
- return 1;
+ return 1; /* or -1, at end of iterator */
case STORE_ATTR:
return -2;
@@ -799,7 +799,7 @@ opcode_stack_effect(int opcode, int oparg)
case COMPARE_OP:
return -1;
case IMPORT_NAME:
- return 0;
+ return -1;
case IMPORT_FROM:
return 1;
@@ -3546,7 +3546,7 @@ dfs(struct compiler *c, basicblock *b, struct assembler *a)
static int
stackdepth_walk(struct compiler *c, basicblock *b, int depth, int maxdepth)
{
- int i;
+ int i, target_depth;
struct instr *instr;
if (b->b_seen || b->b_startdepth >= depth)
return maxdepth;
@@ -3559,8 +3559,17 @@ stackdepth_walk(struct compiler *c, basicblock *b, int depth, int maxdepth)
maxdepth = depth;
assert(depth >= 0); /* invalid code or bug in stackdepth() */
if (instr->i_jrel || instr->i_jabs) {
+ target_depth = depth;
+ if (instr->i_opcode == FOR_ITER) {
+ target_depth = depth-2;
+ } else if (instr->i_opcode == SETUP_FINALLY ||
+ instr->i_opcode == SETUP_EXCEPT) {
+ target_depth = depth+3;
+ if (target_depth > maxdepth)
+ maxdepth = target_depth;
+ }
maxdepth = stackdepth_walk(c, instr->i_target,
- depth, maxdepth);
+ target_depth, maxdepth);
if (instr->i_opcode == JUMP_ABSOLUTE ||
instr->i_opcode == JUMP_FORWARD) {
goto out; /* remaining code is dead */