mirrors
/
cpython
mirror of https://github.com/python/cpython.git
2
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

GH-93678: refactor compiler so that optimizer does not need the assembler and compiler structs (GH-93842)

This commit is contained in:
Irit Katriel 2022-06-21 09:22:17 +01:00 committed by GitHub
parent 77c839c98f
commit 889772fb56
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 171 additions and 161 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Misc/NEWS.d/next/Core and Builtins/2022-06-15-16-45-53.gh-issue-93678.1I_ZT3.rst Normal file
View File

@ -0,0 +1 @@
Refactor compiler optimisation code so that it no longer needs the ``struct assembler`` and ``struct compiler`` passed around. Instead, each function takes the CFG and other data that it actually needs. This will make it possible to test this code directly.

331
Python/compile.c
View File

@ -854,20 +854,26 @@ compiler_set_qualname(struct compiler *c)
/* Allocate a new block and return a pointer to it. /* Allocate a new block and return a pointer to it.
Returns NULL on error. Returns NULL on error.
*/ */
static basicblock * static basicblock *
compiler_new_block(struct compiler *c) new_basicblock()
{ {
basicblock *b; basicblock *b = (basicblock *)PyObject_Calloc(1, sizeof(basicblock));
struct compiler_unit *u;
u = c->u;
b = (basicblock *)PyObject_Calloc(1, sizeof(basicblock));
if (b == NULL) { if (b == NULL) {
PyErr_NoMemory(); PyErr_NoMemory();
return NULL; return NULL;
} }
return b;
}
static basicblock *
compiler_new_block(struct compiler *c)
{
basicblock *b = new_basicblock();
if (b == NULL) {
return NULL;
}
/* Extend the singly linked list of blocks with new block. */ /* Extend the singly linked list of blocks with new block. */
struct compiler_unit *u = c->u;
b->b_list = u->u_blocks; b->b_list = u->u_blocks;
u->u_blocks = b; u->u_blocks = b;
return b; return b;
@ -883,13 +889,25 @@ compiler_use_next_block(struct compiler *c, basicblock *block)
} }
static basicblock * static basicblock *
compiler_copy_block(struct compiler *c, basicblock *block) basicblock_new_b_list_successor(basicblock *prev)
{
basicblock *result = new_basicblock();
if (result == NULL) {
return NULL;
}
result->b_list = prev->b_list;
prev->b_list = result;
return result;
}
static basicblock *
copy_basicblock(basicblock *block)
{ {
/* Cannot copy a block if it has a fallthrough, since /* Cannot copy a block if it has a fallthrough, since
* a block can only have one fallthrough predecessor. * a block can only have one fallthrough predecessor.
*/ */
assert(BB_NO_FALLTHROUGH(block)); assert(BB_NO_FALLTHROUGH(block));
basicblock *result = compiler_new_block(c); basicblock *result = basicblock_new_b_list_successor(block);
if (result == NULL) { if (result == NULL) {
return NULL; return NULL;
} }
@ -1340,8 +1358,9 @@ compiler_add_o(PyObject *dict, PyObject *o)
// Merge const *o* recursively and return constant key object. // Merge const *o* recursively and return constant key object.
static PyObject* static PyObject*
merge_consts_recursive(struct compiler *c, PyObject *o) merge_consts_recursive(PyObject *const_cache, PyObject *o)
{ {
assert(PyDict_CheckExact(const_cache));
// None and Ellipsis are singleton, and key is the singleton. // None and Ellipsis are singleton, and key is the singleton.
// No need to merge object and key. // No need to merge object and key.
if (o == Py_None || o == Py_Ellipsis) { if (o == Py_None || o == Py_Ellipsis) {
@ -1355,22 +1374,22 @@ merge_consts_recursive(struct compiler *c, PyObject *o)
} }
// t is borrowed reference // t is borrowed reference
PyObject *t = PyDict_SetDefault(c->c_const_cache, key, key); PyObject *t = PyDict_SetDefault(const_cache, key, key);
if (t != key) { if (t != key) {
// o is registered in c_const_cache. Just use it. // o is registered in const_cache. Just use it.
Py_XINCREF(t); Py_XINCREF(t);
Py_DECREF(key); Py_DECREF(key);
return t; return t;
} }
// We registered o in c_const_cache. // We registered o in const_cache.
// When o is a tuple or frozenset, we want to merge its // When o is a tuple or frozenset, we want to merge its
// items too. // items too.
if (PyTuple_CheckExact(o)) { if (PyTuple_CheckExact(o)) {
Py_ssize_t len = PyTuple_GET_SIZE(o); Py_ssize_t len = PyTuple_GET_SIZE(o);
for (Py_ssize_t i = 0; i < len; i++) { for (Py_ssize_t i = 0; i < len; i++) {
PyObject *item = PyTuple_GET_ITEM(o, i); PyObject *item = PyTuple_GET_ITEM(o, i);
PyObject *u = merge_consts_recursive(c, item); PyObject *u = merge_consts_recursive(const_cache, item);
if (u == NULL) { if (u == NULL) {
Py_DECREF(key); Py_DECREF(key);
return NULL; return NULL;
@ -1413,7 +1432,7 @@ merge_consts_recursive(struct compiler *c, PyObject *o)
PyObject *item; PyObject *item;
Py_hash_t hash; Py_hash_t hash;
while (_PySet_NextEntry(o, &pos, &item, &hash)) { while (_PySet_NextEntry(o, &pos, &item, &hash)) {
PyObject *k = merge_consts_recursive(c, item); PyObject *k = merge_consts_recursive(const_cache, item);
if (k == NULL) { if (k == NULL) {
Py_DECREF(tuple); Py_DECREF(tuple);
Py_DECREF(key); Py_DECREF(key);
@ -1451,7 +1470,7 @@ merge_consts_recursive(struct compiler *c, PyObject *o)
static Py_ssize_t static Py_ssize_t
compiler_add_const(struct compiler *c, PyObject *o) compiler_add_const(struct compiler *c, PyObject *o)
{ {
PyObject *key = merge_consts_recursive(c, o); PyObject *key = merge_consts_recursive(c->c_const_cache, o);
if (key == NULL) { if (key == NULL) {
return -1; return -1;
} }
@ -6994,34 +7013,25 @@ compiler_match(struct compiler *c, stmt_ty s)
#undef WILDCARD_CHECK #undef WILDCARD_CHECK
#undef WILDCARD_STAR_CHECK #undef WILDCARD_STAR_CHECK
/* End of the compiler section, beginning of the assembler section */ /* 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 { struct assembler {
PyObject *a_bytecode; /* bytes containing bytecode */ PyObject *a_bytecode; /* bytes containing bytecode */
PyObject *a_except_table; /* bytes containing exception table */
basicblock *a_entry;
int a_offset; /* offset into bytecode */ int a_offset; /* offset into bytecode */
PyObject *a_except_table; /* bytes containing exception table */
int a_except_table_off; /* offset into exception table */ int a_except_table_off; /* offset into exception table */
int a_lineno; /* lineno of last emitted instruction */
int a_end_lineno; /* end_lineno of last emitted instruction */
int a_lineno_start; /* bytecode start offset of current lineno */
int a_end_lineno_start; /* bytecode start offset of current end_lineno */
/* Location Info */ /* Location Info */
int a_lineno; /* lineno of last emitted instruction */
PyObject* a_linetable; /* bytes containing location info */ PyObject* a_linetable; /* bytes containing location info */
int a_location_off; /* offset of last written location info frame */ int a_location_off; /* offset of last written location info frame */
}; };
static basicblock** static basicblock**
make_cfg_traversal_stack(basicblock *entry) { make_cfg_traversal_stack(basicblock *entryblock) {
int nblocks = 0; int nblocks = 0;
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
b->b_visited = 0; b->b_visited = 0;
nblocks++; nblocks++;
} }
@ -7047,22 +7057,22 @@ stackdepth_push(basicblock ***sp, basicblock *b, int depth)
* cycles in the flow graph have no net effect on the stack depth. * cycles in the flow graph have no net effect on the stack depth.
*/ */
static int static int
stackdepth(struct compiler *c, basicblock *entry) stackdepth(basicblock *entryblock, int code_flags)
{ {
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
b->b_startdepth = INT_MIN; b->b_startdepth = INT_MIN;
} }
basicblock **stack = make_cfg_traversal_stack(entry); basicblock **stack = make_cfg_traversal_stack(entryblock);
if (!stack) { if (!stack) {
return -1; return -1;
} }
int maxdepth = 0; int maxdepth = 0;
basicblock **sp = stack; basicblock **sp = stack;
if (c->u->u_ste->ste_generator || c->u->u_ste->ste_coroutine) { if (code_flags & (CO_GENERATOR | CO_COROUTINE | CO_ASYNC_GENERATOR)) {
stackdepth_push(&sp, entry, 1); stackdepth_push(&sp, entryblock, 1);
} else { } else {
stackdepth_push(&sp, entry, 0); stackdepth_push(&sp, entryblock, 0);
} }
while (sp != stack) { while (sp != stack) {
@ -7117,11 +7127,10 @@ stackdepth(struct compiler *c, basicblock *entry)
} }
static int static int
assemble_init(struct assembler *a, int nblocks, int firstlineno) assemble_init(struct assembler *a, int firstlineno)
{ {
memset(a, 0, sizeof(struct assembler)); memset(a, 0, sizeof(struct assembler));
a->a_lineno = firstlineno; a->a_lineno = firstlineno;
a->a_end_lineno = firstlineno;
a->a_linetable = NULL; a->a_linetable = NULL;
a->a_location_off = 0; a->a_location_off = 0;
a->a_except_table = NULL; a->a_except_table = NULL;
@ -7137,10 +7146,6 @@ assemble_init(struct assembler *a, int nblocks, int firstlineno)
if (a->a_except_table == NULL) { if (a->a_except_table == NULL) {
goto error; goto error;
} }
if ((size_t)nblocks > SIZE_MAX / sizeof(basicblock *)) {
PyErr_NoMemory();
goto error;
}
return 1; return 1;
error: error:
Py_XDECREF(a->a_bytecode); Py_XDECREF(a->a_bytecode);
@ -7216,8 +7221,8 @@ copy_except_stack(ExceptStack *stack) {
} }
static int static int
label_exception_targets(basicblock *entry) { label_exception_targets(basicblock *entryblock) {
basicblock **todo_stack = make_cfg_traversal_stack(entry); basicblock **todo_stack = make_cfg_traversal_stack(entryblock);
if (todo_stack == NULL) { if (todo_stack == NULL) {
return -1; return -1;
} }
@ -7228,9 +7233,9 @@ label_exception_targets(basicblock *entry) {
return -1; return -1;
} }
except_stack->depth = 0; except_stack->depth = 0;
todo_stack[0] = entry; todo_stack[0] = entryblock;
entry->b_visited = 1; entryblock->b_visited = 1;
entry->b_exceptstack = except_stack; entryblock->b_exceptstack = except_stack;
basicblock **todo = &todo_stack[1]; basicblock **todo = &todo_stack[1];
basicblock *handler = NULL; basicblock *handler = NULL;
while (todo > todo_stack) { while (todo > todo_stack) {
@ -7295,7 +7300,7 @@ label_exception_targets(basicblock *entry) {
} }
} }
#ifdef Py_DEBUG #ifdef Py_DEBUG
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
assert(b->b_exceptstack == NULL); assert(b->b_exceptstack == NULL);
} }
#endif #endif
@ -7308,15 +7313,15 @@ label_exception_targets(basicblock *entry) {
} }
static int static int
mark_warm(basicblock *entry) { mark_warm(basicblock *entryblock) {
basicblock **stack = make_cfg_traversal_stack(entry); basicblock **stack = make_cfg_traversal_stack(entryblock);
if (stack == NULL) { if (stack == NULL) {
return -1; return -1;
} }
basicblock **sp = stack; basicblock **sp = stack;
*sp++ = entry; *sp++ = entryblock;
entry->b_visited = 1; entryblock->b_visited = 1;
while (sp > stack) { while (sp > stack) {
basicblock *b = *(--sp); basicblock *b = *(--sp);
assert(!b->b_except_predecessors); assert(!b->b_except_predecessors);
@ -7339,21 +7344,21 @@ mark_warm(basicblock *entry) {
} }
static int static int
mark_cold(basicblock *entry) { mark_cold(basicblock *entryblock) {
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
assert(!b->b_cold && !b->b_warm); assert(!b->b_cold && !b->b_warm);
} }
if (mark_warm(entry) < 0) { if (mark_warm(entryblock) < 0) {
return -1; return -1;
} }
basicblock **stack = make_cfg_traversal_stack(entry); basicblock **stack = make_cfg_traversal_stack(entryblock);
if (stack == NULL) { if (stack == NULL) {
return -1; return -1;
} }
basicblock **sp = stack; basicblock **sp = stack;
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_except_predecessors) { if (b->b_except_predecessors) {
assert(b->b_except_predecessors == b->b_predecessors); assert(b->b_except_predecessors == b->b_predecessors);
assert(!b->b_warm); assert(!b->b_warm);
@ -7389,20 +7394,20 @@ mark_cold(basicblock *entry) {
} }
static int static int
push_cold_blocks_to_end(struct compiler *c, basicblock *entry, int code_flags) { push_cold_blocks_to_end(basicblock *entryblock, int code_flags) {
if (entry->b_next == NULL) { if (entryblock->b_next == NULL) {
/* single basicblock, no need to reorder */ /* single basicblock, no need to reorder */
return 0; return 0;
} }
if (mark_cold(entry) < 0) { if (mark_cold(entryblock) < 0) {
return -1; return -1;
} }
/* If we have a cold block with fallthrough to a warm block, add */ /* If we have a cold block with fallthrough to a warm block, add */
/* an explicit jump instead of fallthrough */ /* an explicit jump instead of fallthrough */
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_cold && BB_HAS_FALLTHROUGH(b) && b->b_next && b->b_next->b_warm) { if (b->b_cold && BB_HAS_FALLTHROUGH(b) && b->b_next && b->b_next->b_warm) {
basicblock *explicit_jump = compiler_new_block(c); basicblock *explicit_jump = basicblock_new_b_list_successor(b);
if (explicit_jump == NULL) { if (explicit_jump == NULL) {
return -1; return -1;
} }
@ -7414,11 +7419,11 @@ push_cold_blocks_to_end(struct compiler *c, basicblock *entry, int code_flags) {
} }
} }
assert(!entry->b_cold); /* First block can't be cold */ assert(!entryblock->b_cold); /* First block can't be cold */
basicblock *cold_blocks = NULL; basicblock *cold_blocks = NULL;
basicblock *cold_blocks_tail = NULL; basicblock *cold_blocks_tail = NULL;
basicblock *b = entry; basicblock *b = entryblock;
while(b->b_next) { while(b->b_next) {
assert(!b->b_cold); assert(!b->b_cold);
while (b->b_next && !b->b_next->b_cold) { while (b->b_next && !b->b_next->b_cold) {
@ -7457,8 +7462,8 @@ push_cold_blocks_to_end(struct compiler *c, basicblock *entry, int code_flags) {
} }
static void static void
convert_exception_handlers_to_nops(basicblock *entry) { convert_exception_handlers_to_nops(basicblock *entryblock) {
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
for (int i = 0; i < b->b_iused; i++) { for (int i = 0; i < b->b_iused; i++) {
struct instr *instr = &b->b_instr[i]; struct instr *instr = &b->b_instr[i];
if (is_block_push(instr) || instr->i_opcode == POP_BLOCK) { if (is_block_push(instr) || instr->i_opcode == POP_BLOCK) {
@ -7528,13 +7533,13 @@ assemble_emit_exception_table_entry(struct assembler *a, int start, int end, bas
} }
static int static int
assemble_exception_table(struct assembler *a) assemble_exception_table(struct assembler *a, basicblock *entryblock)
{ {
basicblock *b; basicblock *b;
int ioffset = 0; int ioffset = 0;
basicblock *handler = NULL; basicblock *handler = NULL;
int start = -1; int start = -1;
for (b = a->a_entry; b != NULL; b = b->b_next) { for (b = entryblock; b != NULL; b = b->b_next) {
ioffset = b->b_offset; ioffset = b->b_offset;
for (int i = 0; i < b->b_iused; i++) { for (int i = 0; i < b->b_iused; i++) {
struct instr *instr = &b->b_instr[i]; struct instr *instr = &b->b_instr[i];
@ -7727,12 +7732,12 @@ assemble_emit(struct assembler *a, struct instr *i)
} }
static void static void
normalize_jumps(struct assembler *a) normalize_jumps(basicblock *entryblock)
{ {
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
b->b_visited = 0; b->b_visited = 0;
} }
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
b->b_visited = 1; b->b_visited = 1;
if (b->b_iused == 0) { if (b->b_iused == 0) {
continue; continue;
@ -7786,25 +7791,23 @@ normalize_jumps(struct assembler *a)
} }
static void static void
assemble_jump_offsets(struct assembler *a, struct compiler *c) assemble_jump_offsets(basicblock *entryblock)
{ {
basicblock *b;
int bsize, totsize, extended_arg_recompile; int bsize, totsize, extended_arg_recompile;
int i;
/* Compute the size of each block and fixup jump args. /* Compute the size of each block and fixup jump args.
Replace block pointer with position in bytecode. */ Replace block pointer with position in bytecode. */
do { do {
totsize = 0; totsize = 0;
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
bsize = blocksize(b); bsize = blocksize(b);
b->b_offset = totsize; b->b_offset = totsize;
totsize += bsize; totsize += bsize;
} }
extended_arg_recompile = 0; extended_arg_recompile = 0;
for (b = c->u->u_blocks; b != NULL; b = b->b_list) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
bsize = b->b_offset; bsize = b->b_offset;
for (i = 0; i < b->b_iused; i++) { for (int i = 0; i < b->b_iused; i++) {
struct instr *instr = &b->b_instr[i]; struct instr *instr = &b->b_instr[i];
int isize = instr_size(instr); int isize = instr_size(instr);
/* Relative jumps are computed relative to /* Relative jumps are computed relative to
@ -7917,17 +7920,17 @@ scan_block_for_local(int target, basicblock *b, bool unsafe_to_start,
#undef MAYBE_PUSH #undef MAYBE_PUSH
static int static int
add_checks_for_loads_of_unknown_variables(struct assembler *a, add_checks_for_loads_of_unknown_variables(basicblock *entryblock,
struct compiler *c) struct compiler *c)
{ {
basicblock **stack = make_cfg_traversal_stack(a->a_entry); basicblock **stack = make_cfg_traversal_stack(entryblock);
if (stack == NULL) { if (stack == NULL) {
return -1; return -1;
} }
Py_ssize_t nparams = PyList_GET_SIZE(c->u->u_ste->ste_varnames); Py_ssize_t nparams = PyList_GET_SIZE(c->u->u_ste->ste_varnames);
int nlocals = (int)PyDict_GET_SIZE(c->u->u_varnames); int nlocals = (int)PyDict_GET_SIZE(c->u->u_varnames);
for (int target = 0; target < nlocals; target++) { for (int target = 0; target < nlocals; target++) {
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
b->b_visited = 0; b->b_visited = 0;
} }
basicblock **stack_top = stack; basicblock **stack_top = stack;
@ -7937,10 +7940,10 @@ add_checks_for_loads_of_unknown_variables(struct assembler *a,
// which are the entry block and any DELETE_FAST statements. // which are the entry block and any DELETE_FAST statements.
if (target >= nparams) { if (target >= nparams) {
// only non-parameter locals start out uninitialized. // only non-parameter locals start out uninitialized.
*(stack_top++) = a->a_entry; *(stack_top++) = entryblock;
a->a_entry->b_visited = 1; entryblock->b_visited = 1;
} }
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
scan_block_for_local(target, b, false, &stack_top); scan_block_for_local(target, b, false, &stack_top);
} }
@ -8034,15 +8037,16 @@ compute_code_flags(struct compiler *c)
// Merge *obj* with constant cache. // Merge *obj* with constant cache.
// Unlike merge_consts_recursive(), this function doesn't work recursively. // Unlike merge_consts_recursive(), this function doesn't work recursively.
static int static int
merge_const_one(struct compiler *c, PyObject **obj) merge_const_one(PyObject *const_cache, PyObject **obj)
{ {
PyDict_CheckExact(const_cache);
PyObject *key = _PyCode_ConstantKey(*obj); PyObject *key = _PyCode_ConstantKey(*obj);
if (key == NULL) { if (key == NULL) {
return 0; return 0;
} }
// t is borrowed reference // t is borrowed reference
PyObject *t = PyDict_SetDefault(c->c_const_cache, key, key); PyObject *t = PyDict_SetDefault(const_cache, key, key);
Py_DECREF(key); Py_DECREF(key);
if (t == NULL) { if (t == NULL) {
return 0; return 0;
@ -8125,7 +8129,7 @@ makecode(struct compiler *c, struct assembler *a, PyObject *constslist,
if (!names) { if (!names) {
goto error; goto error;
} }
if (!merge_const_one(c, &names)) { if (!merge_const_one(c->c_const_cache, &names)) {
goto error; goto error;
} }
@ -8133,7 +8137,7 @@ makecode(struct compiler *c, struct assembler *a, PyObject *constslist,
if (consts == NULL) { if (consts == NULL) {
goto error; goto error;
} }
if (!merge_const_one(c, &consts)) { if (!merge_const_one(c->c_const_cache, &consts)) {
goto error; goto error;
} }
@ -8184,7 +8188,7 @@ makecode(struct compiler *c, struct assembler *a, PyObject *constslist,
goto error; goto error;
} }
if (!merge_const_one(c, &localsplusnames)) { if (!merge_const_one(c->c_const_cache, &localsplusnames)) {
goto error; goto error;
} }
con.localsplusnames = localsplusnames; con.localsplusnames = localsplusnames;
@ -8249,14 +8253,14 @@ static int
normalize_basic_block(basicblock *bb); normalize_basic_block(basicblock *bb);
static int static int
optimize_cfg(struct compiler *c, struct assembler *a, PyObject *consts); optimize_cfg(basicblock *entryblock, PyObject *consts, PyObject *const_cache);
static int static int
trim_unused_consts(struct assembler *a, PyObject *consts); trim_unused_consts(basicblock *entryblock, PyObject *consts);
/* Duplicates exit BBs, so that line numbers can be propagated to them */ /* Duplicates exit BBs, so that line numbers can be propagated to them */
static int static int
duplicate_exits_without_lineno(struct compiler *c); duplicate_exits_without_lineno(basicblock *entryblock);
static int static int
extend_block(basicblock *bb); extend_block(basicblock *bb);
@ -8390,10 +8394,10 @@ insert_prefix_instructions(struct compiler *c, basicblock *entryblock,
* The resulting line number may not be correct according to PEP 626, * The resulting line number may not be correct according to PEP 626,
* but should be "good enough", and no worse than in older versions. */ * but should be "good enough", and no worse than in older versions. */
static void static void
guarantee_lineno_for_exits(struct assembler *a, int firstlineno) { guarantee_lineno_for_exits(basicblock *entryblock, int firstlineno) {
int lineno = firstlineno; int lineno = firstlineno;
assert(lineno > 0); assert(lineno > 0);
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_iused == 0) { if (b->b_iused == 0) {
continue; continue;
} }
@ -8460,21 +8464,21 @@ fix_cell_offsets(struct compiler *c, basicblock *entryblock, int *fixedmap)
} }
static void static void
propagate_line_numbers(struct assembler *a); propagate_line_numbers(basicblock *entryblock);
static void static void
eliminate_empty_basic_blocks(basicblock *entry); eliminate_empty_basic_blocks(basicblock *entryblock);
static void static void
remove_redundant_jumps(basicblock *entry) { remove_redundant_jumps(basicblock *entryblock) {
/* If a non-empty block ends with a jump instruction, check if the next /* If a non-empty block ends with a jump instruction, check if the next
* non-empty block reached through normal flow control is the target * non-empty block reached through normal flow control is the target
* of that jump. If it is, then the jump instruction is redundant and * of that jump. If it is, then the jump instruction is redundant and
* can be deleted. * can be deleted.
*/ */
int removed = 0; int removed = 0;
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_iused > 0) { if (b->b_iused > 0) {
struct instr *b_last_instr = &b->b_instr[b->b_iused - 1]; struct instr *b_last_instr = &b->b_instr[b->b_iused - 1];
assert(!IS_ASSEMBLER_OPCODE(b_last_instr->i_opcode)); assert(!IS_ASSEMBLER_OPCODE(b_last_instr->i_opcode));
@ -8489,16 +8493,13 @@ remove_redundant_jumps(basicblock *entry) {
} }
} }
if (removed) { if (removed) {
eliminate_empty_basic_blocks(entry); eliminate_empty_basic_blocks(entryblock);
} }
} }
static PyCodeObject * static PyCodeObject *
assemble(struct compiler *c, int addNone) assemble(struct compiler *c, int addNone)
{ {
basicblock *b, *entryblock;
struct assembler a;
int j, nblocks;
PyCodeObject *co = NULL; PyCodeObject *co = NULL;
PyObject *consts = NULL; PyObject *consts = NULL;
@ -8527,15 +8528,6 @@ assemble(struct compiler *c, int addNone)
} }
} }
nblocks = 0;
entryblock = NULL;
for (b = c->u->u_blocks; b != NULL; b = b->b_list) {
nblocks++;
entryblock = b;
assert(b->b_warm == 0 && b->b_cold == 0);
}
assert(entryblock != NULL);
assert(PyDict_GET_SIZE(c->u->u_varnames) < INT_MAX); assert(PyDict_GET_SIZE(c->u->u_varnames) < INT_MAX);
assert(PyDict_GET_SIZE(c->u->u_cellvars) < INT_MAX); assert(PyDict_GET_SIZE(c->u->u_cellvars) < INT_MAX);
assert(PyDict_GET_SIZE(c->u->u_freevars) < INT_MAX); assert(PyDict_GET_SIZE(c->u->u_freevars) < INT_MAX);
@ -8550,6 +8542,18 @@ assemble(struct compiler *c, int addNone)
goto error; goto error;
} }
int nblocks = 0;
basicblock *entryblock = NULL;
for (basicblock *b = c->u->u_blocks; b != NULL; b = b->b_list) {
nblocks++;
entryblock = b;
}
assert(entryblock != NULL);
if ((size_t)nblocks > SIZE_MAX / sizeof(basicblock *)) {
PyErr_NoMemory();
goto error;
}
/* Set firstlineno if it wasn't explicitly set. */ /* Set firstlineno if it wasn't explicitly set. */
if (!c->u->u_firstlineno) { if (!c->u->u_firstlineno) {
if (entryblock->b_instr && entryblock->b_instr->i_loc.lineno) { if (entryblock->b_instr && entryblock->b_instr->i_loc.lineno) {
@ -8565,10 +8569,6 @@ assemble(struct compiler *c, int addNone)
goto error; goto error;
} }
if (!assemble_init(&a, nblocks, c->u->u_firstlineno))
goto error;
a.a_entry = entryblock;
int numdropped = fix_cell_offsets(c, entryblock, cellfixedoffsets); int numdropped = fix_cell_offsets(c, entryblock, cellfixedoffsets);
PyMem_Free(cellfixedoffsets); // At this point we're done with it. PyMem_Free(cellfixedoffsets); // At this point we're done with it.
cellfixedoffsets = NULL; cellfixedoffsets = NULL;
@ -8582,18 +8582,19 @@ assemble(struct compiler *c, int addNone)
goto error; goto error;
} }
if (optimize_cfg(c, &a, consts)) { if (optimize_cfg(entryblock, consts, c->c_const_cache)) {
goto error; goto error;
} }
if (duplicate_exits_without_lineno(c)) { if (duplicate_exits_without_lineno(entryblock)) {
return NULL; return NULL;
} }
if (trim_unused_consts(&a, consts)) { if (trim_unused_consts(entryblock, consts)) {
goto error; goto error;
} }
propagate_line_numbers(&a); propagate_line_numbers(entryblock);
guarantee_lineno_for_exits(&a, c->u->u_firstlineno); guarantee_lineno_for_exits(entryblock, c->u->u_firstlineno);
int maxdepth = stackdepth(c, entryblock);
int maxdepth = stackdepth(entryblock, code_flags);
if (maxdepth < 0) { if (maxdepth < 0) {
goto error; goto error;
} }
@ -8609,62 +8610,67 @@ assemble(struct compiler *c, int addNone)
} }
convert_exception_handlers_to_nops(entryblock); convert_exception_handlers_to_nops(entryblock);
if (push_cold_blocks_to_end(c, entryblock, code_flags) < 0) { if (push_cold_blocks_to_end(entryblock, code_flags) < 0) {
goto error; goto error;
} }
remove_redundant_jumps(entryblock); remove_redundant_jumps(entryblock);
assert(a.a_entry == entryblock);
for (basicblock *b = entryblock; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
clean_basic_block(b); clean_basic_block(b);
} }
/* Order of basic blocks must have been determined by now */ /* Order of basic blocks must have been determined by now */
normalize_jumps(&a); normalize_jumps(entryblock);
if (add_checks_for_loads_of_unknown_variables(&a, c) < 0) { if (add_checks_for_loads_of_unknown_variables(entryblock, c) < 0) {
goto error; goto error;
} }
/* Can't modify the bytecode after computing jump offsets. */ /* Can't modify the bytecode after computing jump offsets. */
assemble_jump_offsets(&a, c); assemble_jump_offsets(entryblock);
/* Create assembler */
struct assembler a;
if (!assemble_init(&a, c->u->u_firstlineno))
goto error;
/* Emit code. */ /* Emit code. */
for(b = entryblock; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
for (j = 0; j < b->b_iused; j++) for (int j = 0; j < b->b_iused; j++)
if (!assemble_emit(&a, &b->b_instr[j])) if (!assemble_emit(&a, &b->b_instr[j]))
goto error; goto error;
} }
/* Emit location info */ /* Emit location info */
a.a_lineno = c->u->u_firstlineno; a.a_lineno = c->u->u_firstlineno;
for(b = entryblock; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
for (j = 0; j < b->b_iused; j++) for (int j = 0; j < b->b_iused; j++)
if (!assemble_emit_location(&a, &b->b_instr[j])) if (!assemble_emit_location(&a, &b->b_instr[j]))
goto error; goto error;
} }
if (!assemble_exception_table(&a)) { if (!assemble_exception_table(&a, entryblock)) {
goto error; goto error;
} }
if (_PyBytes_Resize(&a.a_except_table, a.a_except_table_off) < 0) { if (_PyBytes_Resize(&a.a_except_table, a.a_except_table_off) < 0) {
goto error; goto error;
} }
if (!merge_const_one(c, &a.a_except_table)) { if (!merge_const_one(c->c_const_cache, &a.a_except_table)) {
goto error; goto error;
} }
if (_PyBytes_Resize(&a.a_linetable, a.a_location_off) < 0) { if (_PyBytes_Resize(&a.a_linetable, a.a_location_off) < 0) {
goto error; goto error;
} }
if (!merge_const_one(c, &a.a_linetable)) { if (!merge_const_one(c->c_const_cache, &a.a_linetable)) {
goto error; goto error;
} }
if (_PyBytes_Resize(&a.a_bytecode, a.a_offset * sizeof(_Py_CODEUNIT)) < 0) { if (_PyBytes_Resize(&a.a_bytecode, a.a_offset * sizeof(_Py_CODEUNIT)) < 0) {
goto error; goto error;
} }
if (!merge_const_one(c, &a.a_bytecode)) { if (!merge_const_one(c->c_const_cache, &a.a_bytecode)) {
goto error; goto error;
} }
@ -8703,11 +8709,12 @@ get_const_value(int opcode, int oparg, PyObject *co_consts)
Called with codestr pointing to the first LOAD_CONST. Called with codestr pointing to the first LOAD_CONST.
*/ */
static int static int
fold_tuple_on_constants(struct compiler *c, fold_tuple_on_constants(PyObject *const_cache,
struct instr *inst, struct instr *inst,
int n, PyObject *consts) int n, PyObject *consts)
{ {
/* Pre-conditions */ /* Pre-conditions */
assert(PyDict_CheckExact(const_cache));
assert(PyList_CheckExact(consts)); assert(PyList_CheckExact(consts));
assert(inst[n].i_opcode == BUILD_TUPLE); assert(inst[n].i_opcode == BUILD_TUPLE);
assert(inst[n].i_oparg == n); assert(inst[n].i_oparg == n);
@ -8732,7 +8739,7 @@ fold_tuple_on_constants(struct compiler *c,
} }
PyTuple_SET_ITEM(newconst, i, constant); PyTuple_SET_ITEM(newconst, i, constant);
} }
if (merge_const_one(c, &newconst) == 0) { if (merge_const_one(const_cache, &newconst) == 0) {
Py_DECREF(newconst); Py_DECREF(newconst);
return -1; return -1;
} }
@ -8955,8 +8962,9 @@ jump_thread(struct instr *inst, struct instr *target, int opcode)
/* Optimization */ /* Optimization */
static int static int
optimize_basic_block(struct compiler *c, basicblock *bb, PyObject *consts) optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
{ {
assert(PyDict_CheckExact(const_cache));
assert(PyList_CheckExact(consts)); assert(PyList_CheckExact(consts));
struct instr nop; struct instr nop;
nop.i_opcode = NOP; nop.i_opcode = NOP;
@ -9063,7 +9071,7 @@ optimize_basic_block(struct compiler *c, basicblock *bb, PyObject *consts)
} }
} }
if (i >= oparg) { if (i >= oparg) {
if (fold_tuple_on_constants(c, inst-oparg, oparg, consts)) { if (fold_tuple_on_constants(const_cache, inst-oparg, oparg, consts)) {
goto error; goto error;
} }
} }
@ -9295,14 +9303,14 @@ normalize_basic_block(basicblock *bb) {
} }
static int static int
mark_reachable(struct assembler *a) { mark_reachable(basicblock *entryblock) {
basicblock **stack = make_cfg_traversal_stack(a->a_entry); basicblock **stack = make_cfg_traversal_stack(entryblock);
if (stack == NULL) { if (stack == NULL) {
return -1; return -1;
} }
basicblock **sp = stack; basicblock **sp = stack;
a->a_entry->b_predecessors = 1; entryblock->b_predecessors = 1;
*sp++ = a->a_entry; *sp++ = entryblock;
while (sp > stack) { while (sp > stack) {
basicblock *b = *(--sp); basicblock *b = *(--sp);
b->b_visited = 1; b->b_visited = 1;
@ -9336,9 +9344,9 @@ mark_reachable(struct assembler *a) {
} }
static void static void
eliminate_empty_basic_blocks(basicblock *entry) { eliminate_empty_basic_blocks(basicblock *entryblock) {
/* Eliminate empty blocks */ /* Eliminate empty blocks */
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
basicblock *next = b->b_next; basicblock *next = b->b_next;
if (next) { if (next) {
while (next->b_iused == 0 && next->b_next) { while (next->b_iused == 0 && next->b_next) {
@ -9347,7 +9355,7 @@ eliminate_empty_basic_blocks(basicblock *entry) {
b->b_next = next; b->b_next = next;
} }
} }
for (basicblock *b = entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_iused == 0) { if (b->b_iused == 0) {
continue; continue;
} }
@ -9373,8 +9381,8 @@ eliminate_empty_basic_blocks(basicblock *entry) {
* but has no impact on the generated line number events. * but has no impact on the generated line number events.
*/ */
static void static void
propagate_line_numbers(struct assembler *a) { propagate_line_numbers(basicblock *entryblock) {
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_iused == 0) { if (b->b_iused == 0) {
continue; continue;
} }
@ -9415,31 +9423,32 @@ propagate_line_numbers(struct assembler *a) {
*/ */
static int static int
optimize_cfg(struct compiler *c, struct assembler *a, PyObject *consts) optimize_cfg(basicblock *entryblock, PyObject *consts, PyObject *const_cache)
{ {
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { assert(PyDict_CheckExact(const_cache));
if (optimize_basic_block(c, b, consts)) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (optimize_basic_block(const_cache, b, consts)) {
return -1; return -1;
} }
clean_basic_block(b); clean_basic_block(b);
assert(b->b_predecessors == 0); assert(b->b_predecessors == 0);
} }
for (basicblock *b = c->u->u_blocks; b != NULL; b = b->b_list) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (extend_block(b)) { if (extend_block(b)) {
return -1; return -1;
} }
} }
if (mark_reachable(a)) { if (mark_reachable(entryblock)) {
return -1; return -1;
} }
/* Delete unreachable instructions */ /* Delete unreachable instructions */
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_predecessors == 0) { if (b->b_predecessors == 0) {
b->b_iused = 0; b->b_iused = 0;
} }
} }
eliminate_empty_basic_blocks(a->a_entry); eliminate_empty_basic_blocks(entryblock);
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
clean_basic_block(b); clean_basic_block(b);
} }
return 0; return 0;
@ -9447,13 +9456,13 @@ optimize_cfg(struct compiler *c, struct assembler *a, PyObject *consts)
// Remove trailing unused constants. // Remove trailing unused constants.
static int static int
trim_unused_consts(struct assembler *a, PyObject *consts) trim_unused_consts(basicblock *entryblock, PyObject *consts)
{ {
assert(PyList_CheckExact(consts)); assert(PyList_CheckExact(consts));
// The first constant may be docstring; keep it always. // The first constant may be docstring; keep it always.
int max_const_index = 0; int max_const_index = 0;
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
for (int i = 0; i < b->b_iused; i++) { for (int i = 0; i < b->b_iused; i++) {
if ((b->b_instr[i].i_opcode == LOAD_CONST || if ((b->b_instr[i].i_opcode == LOAD_CONST ||
b->b_instr[i].i_opcode == KW_NAMES) && b->b_instr[i].i_opcode == KW_NAMES) &&
@ -9496,15 +9505,15 @@ is_exit_without_lineno(basicblock *b) {
* copy the line number from the sole predecessor block. * copy the line number from the sole predecessor block.
*/ */
static int static int
duplicate_exits_without_lineno(struct compiler *c) duplicate_exits_without_lineno(basicblock *entryblock)
{ {
/* Copy all exit blocks without line number that are targets of a jump. /* Copy all exit blocks without line number that are targets of a jump.
*/ */
for (basicblock *b = c->u->u_blocks; b != NULL; b = b->b_list) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_iused > 0 && is_jump(&b->b_instr[b->b_iused-1])) { if (b->b_iused > 0 && is_jump(&b->b_instr[b->b_iused-1])) {
basicblock *target = b->b_instr[b->b_iused-1].i_target; basicblock *target = b->b_instr[b->b_iused-1].i_target;
if (is_exit_without_lineno(target) && target->b_predecessors > 1) { if (is_exit_without_lineno(target) && target->b_predecessors > 1) {
basicblock *new_target = compiler_copy_block(c, target); basicblock *new_target = copy_basicblock(target);
if (new_target == NULL) { if (new_target == NULL) {
return -1; return -1;
} }
@ -9518,14 +9527,14 @@ duplicate_exits_without_lineno(struct compiler *c)
} }
} }
/* Eliminate empty blocks */ /* Eliminate empty blocks */
for (basicblock *b = c->u->u_blocks; b != NULL; b = b->b_list) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
while (b->b_next && b->b_next->b_iused == 0) { while (b->b_next && b->b_next->b_iused == 0) {
b->b_next = b->b_next->b_next; b->b_next = b->b_next->b_next;
} }
} }
/* Any remaining reachable exit blocks without line number can only be reached by /* Any remaining reachable exit blocks without line number can only be reached by
* fall through, and thus can only have a single predecessor */ * fall through, and thus can only have a single predecessor */
for (basicblock *b = c->u->u_blocks; b != NULL; b = b->b_list) { for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (BB_HAS_FALLTHROUGH(b) && b->b_next && b->b_iused > 0) { if (BB_HAS_FALLTHROUGH(b) && b->b_next && b->b_iused > 0) {
if (is_exit_without_lineno(b->b_next)) { if (is_exit_without_lineno(b->b_next)) {
assert(b->b_next->b_iused > 0); assert(b->b_next->b_iused > 0);