108 lines
2.5 KiB
C
108 lines
2.5 KiB
C
#include "mcg.h"
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static struct ir* get_last_push(struct basicblock* bb)
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{
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int i;
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for (i=bb->irs_count-1; i>=0; i--)
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{
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struct ir* ir = bb->irs[i];
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if (ir->opcode == IR_PUSH)
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return ir;
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if (ir_find(ir, IR_POP))
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return NULL;
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}
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return NULL;
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}
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static struct ir* get_first_pop(struct basicblock* bb)
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{
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int i;
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for (i=0; i<bb->irs_count; i++)
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{
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struct ir* irr;
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struct ir* ir = bb->irs[i];
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if (ir->opcode == IR_PUSH)
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return NULL;
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irr = ir_find(ir, IR_POP);
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if (irr)
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return irr;
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}
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return NULL;
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}
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static void convert_block(struct basicblock* bb)
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{
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int i, j;
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struct ir* ir;
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for (;;)
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{
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struct ir* lastpush = get_last_push(bb);
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if (!lastpush)
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return;
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/* Abort unless *every* success block of this one starts with a pop
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* of the same size... */
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for (i=0; i<bb->outblocks_count; i++)
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{
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struct basicblock* outbb = bb->outblocks[i];
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ir = get_first_pop(outbb);
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if (!ir || (ir->size != lastpush->size))
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return;
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/* Also abort unless *every* predecessor block of the one we've
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* just found *also* ends in a push of the same size. */
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for (j=0; j<outbb->inblocks_count; j++)
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{
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struct basicblock* inbb = outbb->inblocks[i];
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ir = get_last_push(inbb);
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if (!ir || (ir->size != lastpush->size))
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return;
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}
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}
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/* Okay, now we can wire them all up. */
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for (i=0; i<bb->outblocks_count; i++)
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{
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struct basicblock* outbb = bb->outblocks[i];
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struct ir* phi = get_first_pop(outbb);
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phi->opcode = IR_PHI;
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/* Also abort unless *every* predecessor block of the one we've
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* just found *also* ends in a push of the same size. */
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for (j=0; j<outbb->inblocks_count; j++)
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{
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struct basicblock* inbb = outbb->inblocks[j];
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ir = get_last_push(inbb);
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*ir = *ir->left;
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ir->is_sequence = true;
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APPEND(phi->u.phivalue.imports, ir);
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}
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}
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}
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}
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void pass_convert_stack_ops(struct procedure* proc)
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{
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int i;
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for (i=0; i<proc->blocks_count; i++)
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convert_block(proc->blocks[i]);
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}
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/* vim: set sw=4 ts=4 expandtab : */
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