diff options
Diffstat (limited to 'Python/compile.c')
| -rw-r--r-- | Python/compile.c | 115 |
1 files changed, 43 insertions, 72 deletions
diff --git a/Python/compile.c b/Python/compile.c index 9086103..3eb34d8 100644 --- a/Python/compile.c +++ b/Python/compile.c @@ -21,6 +21,8 @@ * objects. */ +#include <stdbool.h> + #include "Python.h" #include "pycore_ast.h" // _PyAST_GetDocString() #include "pycore_compile.h" // _PyFuture_FromAST() @@ -7264,25 +7266,24 @@ fold_rotations(struct instr *inst, int n) } } - -static int -eliminate_jump_to_jump(basicblock *bb, int opcode) { - assert (bb->b_iused > 0); - struct instr *inst = &bb->b_instr[bb->b_iused-1]; - assert (is_jump(inst)); - assert (inst->i_target->b_iused > 0); - struct instr *target = &inst->i_target->b_instr[0]; - if (inst->i_target == target->i_target) { - /* Nothing to do */ - return 0; - } - int lineno = target->i_lineno; - if (add_jump_to_block(bb, opcode, lineno, target->i_target) == 0) { - return -1; +// Attempt to eliminate jumps to jumps by updating inst to jump to +// target->i_target using the provided opcode. Return whether or not the +// optimization was successful. +static bool +jump_thread(struct instr *inst, struct instr *target, int opcode) +{ + assert(is_jump(inst)); + assert(is_jump(target)); + // bpo-45773: If inst->i_target == target->i_target, then nothing actually + // changes (and we fall into an infinite loop): + if (inst->i_lineno == target->i_lineno && + inst->i_target != target->i_target) + { + inst->i_target = target->i_target; + inst->i_opcode = opcode; + return true; } - assert (bb->b_iused >= 2); - bb->b_instr[bb->b_iused-2].i_opcode = NOP; - return 0; + return false; } /* Maximum size of basic block that should be copied in optimizer */ @@ -7399,25 +7400,21 @@ optimize_basic_block(struct compiler *c, basicblock *bb, PyObject *consts) where y+1 is the instruction following the second test. */ case JUMP_IF_FALSE_OR_POP: - switch(target->i_opcode) { + switch (target->i_opcode) { case POP_JUMP_IF_FALSE: - if (inst->i_lineno == target->i_lineno) { - *inst = *target; - i--; - } + i -= jump_thread(inst, target, POP_JUMP_IF_FALSE); break; case JUMP_ABSOLUTE: case JUMP_FORWARD: case JUMP_IF_FALSE_OR_POP: - if (inst->i_lineno == target->i_lineno && - inst->i_target != target->i_target) { - inst->i_target = target->i_target; - i--; - } + i -= jump_thread(inst, target, JUMP_IF_FALSE_OR_POP); break; case JUMP_IF_TRUE_OR_POP: - assert (inst->i_target->b_iused == 1); + case POP_JUMP_IF_TRUE: if (inst->i_lineno == target->i_lineno) { + // We don't need to bother checking for loops here, + // since a block's b_next cannot point to itself: + assert(inst->i_target != inst->i_target->b_next); inst->i_opcode = POP_JUMP_IF_FALSE; inst->i_target = inst->i_target->b_next; --i; @@ -7425,27 +7422,22 @@ optimize_basic_block(struct compiler *c, basicblock *bb, PyObject *consts) break; } break; - case JUMP_IF_TRUE_OR_POP: - switch(target->i_opcode) { + switch (target->i_opcode) { case POP_JUMP_IF_TRUE: - if (inst->i_lineno == target->i_lineno) { - *inst = *target; - i--; - } + i -= jump_thread(inst, target, POP_JUMP_IF_TRUE); break; case JUMP_ABSOLUTE: case JUMP_FORWARD: case JUMP_IF_TRUE_OR_POP: - if (inst->i_lineno == target->i_lineno && - inst->i_target != target->i_target) { - inst->i_target = target->i_target; - i--; - } + i -= jump_thread(inst, target, JUMP_IF_TRUE_OR_POP); break; case JUMP_IF_FALSE_OR_POP: - assert (inst->i_target->b_iused == 1); + case POP_JUMP_IF_FALSE: if (inst->i_lineno == target->i_lineno) { + // We don't need to bother checking for loops here, + // since a block's b_next cannot point to itself: + assert(inst->i_target != inst->i_target->b_next); inst->i_opcode = POP_JUMP_IF_TRUE; inst->i_target = inst->i_target->b_next; --i; @@ -7453,54 +7445,33 @@ optimize_basic_block(struct compiler *c, basicblock *bb, PyObject *consts) break; } break; - case POP_JUMP_IF_FALSE: - switch(target->i_opcode) { + switch (target->i_opcode) { case JUMP_ABSOLUTE: case JUMP_FORWARD: - if (inst->i_lineno == target->i_lineno) { - inst->i_target = target->i_target; - i--; - } - break; + case JUMP_IF_FALSE_OR_POP: + i -= jump_thread(inst, target, POP_JUMP_IF_FALSE); } break; - case POP_JUMP_IF_TRUE: - switch(target->i_opcode) { + switch (target->i_opcode) { case JUMP_ABSOLUTE: case JUMP_FORWARD: - if (inst->i_lineno == target->i_lineno) { - inst->i_target = target->i_target; - i--; - } - break; + case JUMP_IF_TRUE_OR_POP: + i -= jump_thread(inst, target, POP_JUMP_IF_TRUE); } break; - case JUMP_ABSOLUTE: case JUMP_FORWARD: - assert (i == bb->b_iused-1); - switch(target->i_opcode) { - case JUMP_FORWARD: - if (eliminate_jump_to_jump(bb, inst->i_opcode)) { - goto error; - } - break; - + switch (target->i_opcode) { case JUMP_ABSOLUTE: - if (eliminate_jump_to_jump(bb, JUMP_ABSOLUTE)) { - goto error; - } - break; + case JUMP_FORWARD: + i -= jump_thread(inst, target, JUMP_ABSOLUTE); } break; case FOR_ITER: - assert (i == bb->b_iused-1); if (target->i_opcode == JUMP_FORWARD) { - if (eliminate_jump_to_jump(bb, inst->i_opcode)) { - goto error; - } + i -= jump_thread(inst, target, FOR_ITER); } break; case ROT_N: |