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wasm2c: reuse locals

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* Reduce stack usage of a -O0 build of zig1 by 33%.
 * Avoid compiler builtin calls.
This commit is contained in:
Jacob Young 2022-12-08 21:29:42 -05:00 • committed by Andrew Kelley
parent 5c67f9ce7a
commit 6966fb8ca5
2 changed files with 465 additions and 716 deletions
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76
stage1/FuncGen.h
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@ -8,22 +8,27 @@
#include <stdbool.h> #include <stdbool.h>
#include <stdint.h> #include <stdint.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h>
#include <string.h> #include <string.h>
struct Block { struct Block {
uint32_t type; uint32_t type;
uint32_t label; uint32_t label;
uint32_t stack_i; uint32_t stack_i;
uint32_t reuse_i;
}; };
struct FuncGen { struct FuncGen {
int8_t *type; int8_t *type;
uint32_t *reuse;
uint32_t *stack; uint32_t *stack;
struct Block *block; struct Block *block;
uint32_t type_i; uint32_t type_i;
uint32_t reuse_i;
uint32_t stack_i; uint32_t stack_i;
uint32_t block_i; uint32_t block_i;
uint32_t type_len; uint32_t type_len;
uint32_t reuse_len;
uint32_t stack_len; uint32_t stack_len;
uint32_t block_len; uint32_t block_len;
}; };
@ -34,6 +39,7 @@ static void FuncGen_init(struct FuncGen *self) {
static void FuncGen_reset(struct FuncGen *self) { static void FuncGen_reset(struct FuncGen *self) {
self->type_i = 0; self->type_i = 0;
self->reuse_i = 0;
self->stack_i = 0; self->stack_i = 0;
self->block_i = 0; self->block_i = 0;
} }
@ -41,6 +47,7 @@ static void FuncGen_reset(struct FuncGen *self) {
static void FuncGen_free(struct FuncGen *self) { static void FuncGen_free(struct FuncGen *self) {
free(self->block); free(self->block);
free(self->stack); free(self->stack);
free(self->reuse);
free(self->type); free(self->type);
} }
@ -65,22 +72,43 @@ static uint32_t FuncGen_localAlloc(struct FuncGen *self, int8_t type) {
self->type = realloc(self->type, sizeof(int8_t) * self->type_len); self->type = realloc(self->type, sizeof(int8_t) * self->type_len);
if (self->type == NULL) panic("out of memory"); if (self->type == NULL) panic("out of memory");
} }
uint32_t local_i = self->type_i; uint32_t local_idx = self->type_i;
self->type[local_i] = type; self->type[local_idx] = type;
self->type_i += 1; self->type_i += 1;
return local_i; return local_idx;
}
static uint32_t FuncGen_localDeclare(struct FuncGen *self, FILE *out, enum WasmValType val_type) {
uint32_t local_i = FuncGen_localAlloc(self, (int8_t)val_type);
fprintf(out, "%s l%" PRIu32, WasmValType_toC(val_type), local_i);
return local_i;
} }
static enum WasmValType FuncGen_localType(const struct FuncGen *self, uint32_t local_idx) { static enum WasmValType FuncGen_localType(const struct FuncGen *self, uint32_t local_idx) {
return self->type[local_idx]; return self->type[local_idx];
} }
static uint32_t FuncGen_localDeclare(struct FuncGen *self, FILE *out, enum WasmValType val_type) {
uint32_t local_idx = FuncGen_localAlloc(self, (int8_t)val_type);
fprintf(out, "%s l%" PRIu32, WasmValType_toC(val_type), local_idx);
return local_idx;
}
static uint32_t FuncGen_reuseTop(const struct FuncGen *self) {
return self->block_i > 0 ? self->block[self->block_i - 1].reuse_i : 0;
}
static void FuncGen_reuseReset(struct FuncGen *self) {
self->reuse_i = FuncGen_reuseTop(self);
}
static uint32_t FuncGen_reuseLocal(struct FuncGen *self, FILE *out, enum WasmValType val_type) {
for (uint32_t i = FuncGen_reuseTop(self); i < self->reuse_i; i += 1) {
uint32_t local_idx = self->reuse[i];
if (FuncGen_localType(self, local_idx) == val_type) {
self->reuse_i -= 1;
self->reuse[i] = self->reuse[self->reuse_i];
fprintf(out, "l%" PRIu32, local_idx);
return local_idx;
}
}
return FuncGen_localDeclare(self, out, val_type);
}
static void FuncGen_stackPush(struct FuncGen *self, FILE *out, enum WasmValType val_type) { static void FuncGen_stackPush(struct FuncGen *self, FILE *out, enum WasmValType val_type) {
if (self->stack_i == self->stack_len) { if (self->stack_i == self->stack_len) {
self->stack_len += 10; self->stack_len += 10;
@ -89,8 +117,7 @@ static void FuncGen_stackPush(struct FuncGen *self, FILE *out, enum WasmValType
if (self->stack == NULL) panic("out of memory"); if (self->stack == NULL) panic("out of memory");
} }
FuncGen_indent(self, out); FuncGen_indent(self, out);
fputs("const ", out); self->stack[self->stack_i] = FuncGen_reuseLocal(self, out, val_type);
self->stack[self->stack_i] = FuncGen_localDeclare(self, out, val_type);
self->stack_i += 1; self->stack_i += 1;
fputs(" = ", out); fputs(" = ", out);
} }
@ -100,8 +127,17 @@ static uint32_t FuncGen_stackAt(const struct FuncGen *self, uint32_t stack_idx)
} }
static uint32_t FuncGen_stackPop(struct FuncGen *self) { static uint32_t FuncGen_stackPop(struct FuncGen *self) {
if (self->reuse_i == self->reuse_len) {
self->reuse_len += 10;
self->reuse_len *= 2;
self->reuse = realloc(self->reuse, sizeof(uint32_t) * self->reuse_len);
if (self->reuse == NULL) panic("out of memory");
}
self->stack_i -= 1; self->stack_i -= 1;
return self->stack[self->stack_i]; uint32_t local_idx = self->stack[self->stack_i];
self->reuse[self->reuse_i] = local_idx;
self->reuse_i += 1;
return local_idx;
} }
static void FuncGen_label(struct FuncGen *self, FILE *out, uint32_t label) { static void FuncGen_label(struct FuncGen *self, FILE *out, uint32_t label) {
@ -118,7 +154,6 @@ static void FuncGen_blockBegin(struct FuncGen *self, FILE *out, enum WasmOpcode
self->block = realloc(self->block, sizeof(struct Block) * self->block_len); self->block = realloc(self->block, sizeof(struct Block) * self->block_len);
if (self->block == NULL) panic("out of memory"); if (self->block == NULL) panic("out of memory");
} }
uint32_t label = FuncGen_localAlloc(self, type < 0 ? ~(int8_t)kind : (int8_t)kind);
if (kind == WasmOpcode_if) { if (kind == WasmOpcode_if) {
FuncGen_indent(self, out); FuncGen_indent(self, out);
@ -128,11 +163,24 @@ static void FuncGen_blockBegin(struct FuncGen *self, FILE *out, enum WasmOpcode
fputs("{\n", out); fputs("{\n", out);
} }
uint32_t label = FuncGen_localAlloc(self, type < 0 ? ~(int8_t)kind : (int8_t)kind);
self->block[self->block_i].type = type < 0 ? ~type : type; self->block[self->block_i].type = type < 0 ? ~type : type;
self->block[self->block_i].label = label; self->block[self->block_i].label = label;
self->block[self->block_i].stack_i = self->stack_i; self->block[self->block_i].stack_i = self->stack_i;
self->block[self->block_i].reuse_i = self->reuse_i;
self->block_i += 1; self->block_i += 1;
if (kind == WasmOpcode_loop) FuncGen_label(self, out, label); if (kind == WasmOpcode_loop) FuncGen_label(self, out, label);
uint32_t reuse_top = FuncGen_reuseTop(self);
uint32_t reuse_n = self->reuse_i - reuse_top;
if (reuse_n > self->reuse_len - self->reuse_i) {
self->reuse_len += 10;
self->reuse_len *= 2;
self->reuse = realloc(self->reuse, sizeof(uint32_t) * self->reuse_len);
if (self->reuse == NULL) panic("out of memory");
}
memcpy(&self->reuse[self->reuse_i], &self->reuse[reuse_top], sizeof(uint32_t) * reuse_n);
self->reuse_i += reuse_n;
} }
static enum WasmOpcode FuncGen_blockKind(const struct FuncGen *self, uint32_t label_idx) { static enum WasmOpcode FuncGen_blockKind(const struct FuncGen *self, uint32_t label_idx) {
@ -165,6 +213,8 @@ static void FuncGen_blockEnd(struct FuncGen *self, FILE *out) {
fprintf(out, "// stack mismatch %u != %u\n", self->stack_i, self->block[self->block_i].stack_i); fprintf(out, "// stack mismatch %u != %u\n", self->stack_i, self->block[self->block_i].stack_i);
} }
self->stack_i = self->block[self->block_i].stack_i; self->stack_i = self->block[self->block_i].stack_i;
self->reuse_i = self->block[self->block_i].reuse_i;
} }
static bool FuncGen_done(const struct FuncGen *self) { static bool FuncGen_done(const struct FuncGen *self) {

1105
stage1/wasm2c.c
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