zig/stage1/FuncGen.h
Jacob Young 6966fb8ca5 wasm2c: reuse locals
* Reduce stack usage of a -O0 build of zig1 by 33%.
 * Avoid compiler builtin calls.
2022-12-09 03:45:29 -05:00

225 lines
7.0 KiB
C

#ifndef FUNC_GEN_H
#define FUNC_GEN_H
#include "panic.h"
#include "wasm.h"
#include <inttypes.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct Block {
uint32_t type;
uint32_t label;
uint32_t stack_i;
uint32_t reuse_i;
};
struct FuncGen {
int8_t *type;
uint32_t *reuse;
uint32_t *stack;
struct Block *block;
uint32_t type_i;
uint32_t reuse_i;
uint32_t stack_i;
uint32_t block_i;
uint32_t type_len;
uint32_t reuse_len;
uint32_t stack_len;
uint32_t block_len;
};
static void FuncGen_init(struct FuncGen *self) {
memset(self, 0, sizeof(struct FuncGen));
}
static void FuncGen_reset(struct FuncGen *self) {
self->type_i = 0;
self->reuse_i = 0;
self->stack_i = 0;
self->block_i = 0;
}
static void FuncGen_free(struct FuncGen *self) {
free(self->block);
free(self->stack);
free(self->reuse);
free(self->type);
}
static void FuncGen_outdent(struct FuncGen *self, FILE *out) {
for (uint32_t i = 0; i < self->block_i; i += 1) fputs(" ", out);
}
static void FuncGen_indent(struct FuncGen *self, FILE *out) {
FuncGen_outdent(self, out);
fputs(" ", out);
}
static void FuncGen_cont(struct FuncGen *self, FILE *out) {
FuncGen_indent(self, out);
fputs(" ", out);
}
static uint32_t FuncGen_localAlloc(struct FuncGen *self, int8_t type) {
if (self->type_i == self->type_len) {
self->type_len += 10;
self->type_len *= 2;
self->type = realloc(self->type, sizeof(int8_t) * self->type_len);
if (self->type == NULL) panic("out of memory");
}
uint32_t local_idx = self->type_i;
self->type[local_idx] = type;
self->type_i += 1;
return local_idx;
}
static enum WasmValType FuncGen_localType(const struct FuncGen *self, uint32_t 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) {
if (self->stack_i == self->stack_len) {
self->stack_len += 10;
self->stack_len *= 2;
self->stack = realloc(self->stack, sizeof(uint32_t) * self->stack_len);
if (self->stack == NULL) panic("out of memory");
}
FuncGen_indent(self, out);
self->stack[self->stack_i] = FuncGen_reuseLocal(self, out, val_type);
self->stack_i += 1;
fputs(" = ", out);
}
static uint32_t FuncGen_stackAt(const struct FuncGen *self, uint32_t stack_idx) {
return self->stack[self->stack_i - 1 - stack_idx];
}
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;
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) {
FuncGen_indent(self, out);
fprintf(out, "goto l%" PRIu32 ";\n", label);
FuncGen_outdent(self, out);
fprintf(out, "l%" PRIu32 ":;\n", label);
}
static void FuncGen_blockBegin(struct FuncGen *self, FILE *out, enum WasmOpcode kind, int64_t type) {
if (self->block_i == self->block_len) {
self->block_len += 10;
self->block_len *= 2;
self->block = realloc(self->block, sizeof(struct Block) * self->block_len);
if (self->block == NULL) panic("out of memory");
}
if (kind == WasmOpcode_if) {
FuncGen_indent(self, out);
fprintf(out, "if (l%" PRIu32 ") {\n", FuncGen_stackPop(self));
} else if (EXTRA_BRACES) {
FuncGen_indent(self, 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].label = label;
self->block[self->block_i].stack_i = self->stack_i;
self->block[self->block_i].reuse_i = self->reuse_i;
self->block_i += 1;
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) {
int8_t kind = self->type[self->block[self->block_i - 1 - label_idx].label];
return (enum WasmOpcode)(kind < 0 ? ~kind : kind);
}
static int64_t FuncGen_blockType(const struct FuncGen *self, uint32_t label_idx) {
struct Block *block = &self->block[self->block_i - 1 - label_idx];
return self->type[block->label] < 0 ? ~(int64_t)block->type : (int64_t)block->type;
}
static uint32_t FuncGen_blockLabel(const struct FuncGen *self, uint32_t label_idx) {
return self->block[self->block_i - 1 - label_idx].label;
}
static void FuncGen_blockEnd(struct FuncGen *self, FILE *out) {
enum WasmOpcode kind = FuncGen_blockKind(self, 0);
uint32_t label = FuncGen_blockLabel(self, 0);
if (kind != WasmOpcode_loop) FuncGen_label(self, out, label);
self->block_i -= 1;
if (EXTRA_BRACES || kind == WasmOpcode_if) {
FuncGen_indent(self, out);
fputs("}\n", out);
}
if (self->stack_i != self->block[self->block_i].stack_i) {
FuncGen_indent(self, out);
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->reuse_i = self->block[self->block_i].reuse_i;
}
static bool FuncGen_done(const struct FuncGen *self) {
return self->block_i == 0;
}
#endif /* FUNC_GEN_H */