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authorRaymond Hettinger <python@rcn.com>2004-10-30 08:55:08 (GMT)
committerRaymond Hettinger <python@rcn.com>2004-10-30 08:55:08 (GMT)
commiteffb3931ead28d47d240a113c85e8e494273ebfc (patch)
treeb775b4baa2c554111a6ad485bea05cb60fdc6df2 /Python
parent0c1b253fc04f9d86193e87b93216d73076fb3fe8 (diff)
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Adopt some peepholer suggestions from Armin Rigo:
* Use simpler, faster two pass algorithm for markblocks(). * Free the blocks variable if not NULL and exiting without change. * Verify that the rest of the compiler has not set an exception. * Make the test for tuple of constants less restrictive. * Embellish the comment for chained conditional jumps.
Diffstat (limited to 'Python')
-rw-r--r--Python/compile.c35
1 files changed, 20 insertions, 15 deletions
diff --git a/Python/compile.c b/Python/compile.c
index 37793ca..137b46d 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -406,14 +406,10 @@ tuple_of_constants(unsigned char *codestr, int n, PyObject *consts)
/* Pre-conditions */
assert(PyList_CheckExact(consts));
- assert(codestr[0] == LOAD_CONST);
assert(codestr[n*3] == BUILD_TUPLE);
assert(GETARG(codestr, (n*3)) == n);
-
- /* Verify chain of n load_constants */
for (i=0 ; i<n ; i++)
- if (codestr[i*3] != LOAD_CONST)
- return 0;
+ assert(codestr[i*3] == LOAD_CONST);
/* Buildup new tuple of constants */
newconst = PyTuple_New(n);
@@ -447,11 +443,13 @@ static unsigned int *
markblocks(unsigned char *code, int len)
{
unsigned int *blocks = PyMem_Malloc(len*sizeof(int));
- int i,j, opcode, oldblock, newblock, blockcnt = 0;
+ int i,j, opcode, blockcnt = 0;
if (blocks == NULL)
return NULL;
memset(blocks, 0, len*sizeof(int));
+
+ /* Mark labels in the first pass */
for (i=0 ; i<len ; i+=CODESIZE(opcode)) {
opcode = code[i];
switch (opcode) {
@@ -465,16 +463,15 @@ markblocks(unsigned char *code, int len)
case SETUP_EXCEPT:
case SETUP_FINALLY:
j = GETJUMPTGT(code, i);
- oldblock = blocks[j];
- newblock = ++blockcnt;
- for (; j<len ; j++) {
- if (blocks[j] != (unsigned)oldblock)
- break;
- blocks[j] = newblock;
- }
+ blocks[j] = 1;
break;
}
}
+ /* Build block numbers in the second pass */
+ for (i=0 ; i<len ; i++) {
+ blockcnt += blocks[i]; /* increment blockcnt over labels */
+ blocks[i] = blockcnt;
+ }
return blocks;
}
@@ -503,9 +500,13 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
int *addrmap = NULL;
int new_line, cum_orig_line, last_line, tabsiz;
int cumlc=0, lastlc=0; /* Count runs of consecutive LOAD_CONST codes */
- unsigned int *blocks;
+ unsigned int *blocks = NULL;
char *name;
+ /* Bail out if an exception is set */
+ if (PyErr_Occurred())
+ goto exitUnchanged;
+
/* Bypass optimization when the lineno table is too complex */
assert(PyString_Check(lineno_obj));
lineno = PyString_AS_STRING(lineno_obj);
@@ -614,7 +615,7 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
j = GETARG(codestr, i);
h = i - 3 * j;
if (h >= 0 &&
- j == lastlc &&
+ j <= lastlc &&
codestr[h] == LOAD_CONST &&
ISBASICBLOCK(blocks, h, 3*(j+1)) &&
tuple_of_constants(&codestr[h], j, consts)) {
@@ -647,6 +648,8 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
result of the first test implies the success of a similar
test or the failure of the opposite test.
Arises in code like:
+ "if a and b:"
+ "if a or b:"
"a and b or c"
"a and b and c"
x:JUMP_IF_FALSE y y:JUMP_IF_FALSE z --> x:JUMP_IF_FALSE z
@@ -755,6 +758,8 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
return code;
exitUnchanged:
+ if (blocks != NULL)
+ PyMem_Free(blocks);
if (addrmap != NULL)
PyMem_Free(addrmap);
if (codestr != NULL)