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| | /*
* Copyright (C) 2024 olang maintainers
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include "codegen_aarch64.h"
#include "list.h"
#define SYS_exit (93)
/**
* ───────────────────────────────────────────────────────────────────
* Arch/ABI Instruction System Ret Ret Error Notes
* call # val val2
* ───────────────────────────────────────────────────────────────────
* arm64 svc #0 w8 x0 x1 -
* ──────────────────────────────────────────────────────────────
* Arch/ABI arg1 arg2 arg3 arg4 arg5 arg6 arg7 Notes
* ──────────────────────────────────────────────────────────────
* arm64 x0 x1 x2 x3 x4 x5 -
*/
static void
codegen_aarch64_emit_start_entrypoint(FILE *out);
static void
codegen_aarch64_emit_function(FILE *out, ast_fn_definition_t *fn);
void
codegen_aarch64_emit_translation_unit(FILE *out, ast_node_t *node)
{
codegen_aarch64_emit_start_entrypoint(out);
assert(node->kind == AST_NODE_TRANSLATION_UNIT);
ast_translation_unit_t translation_unit = node->as_translation_unit;
list_item_t *item = list_head(translation_unit.decls);
bool main_found = false;
while (item != NULL) {
ast_node_t *decl = (ast_node_t *)item->value;
if (decl->kind == AST_NODE_FN_DEF) {
ast_fn_definition_t fn = decl->as_fn_def;
codegen_aarch64_emit_function(out, &fn);
main_found = main_found || string_view_eq_to_cstr(fn.id, "main");
} else {
assert(0 && "translation unit only supports function declarations");
}
item = list_next(item);
}
assert(main_found && "main function is required.");
}
static void
codegen_aarch64_emit_start_entrypoint(FILE *out)
{
fprintf(out, ".text\n");
fprintf(out, ".globl _start\n\n");
fprintf(out, "_start:\n");
fprintf(out, " bl main\n");
fprintf(out, " mov w8, #%d\n", SYS_exit);
fprintf(out, " svc #0\n");
}
static void
codegen_aarch64_emit_function(FILE *out, ast_fn_definition_t *fn)
{
ast_node_t *block_node = fn->block;
assert(block_node->kind == AST_NODE_BLOCK);
ast_block_t block = block_node->as_block;
assert(list_size(block.nodes) == 1);
list_item_t *nodes_item = list_get(block.nodes, 0);
ast_node_t *return_node = nodes_item->value;
assert(return_node->kind == AST_NODE_RETURN_STMT);
ast_return_stmt_t return_stmt = return_node->as_return_stmt;
ast_node_t *literal_node = return_stmt.expr;
assert(literal_node->kind == AST_NODE_LITERAL);
ast_literal_t literal_u32 = literal_node->as_literal;
assert(literal_u32.kind == AST_LITERAL_U32);
uint32_t exit_code = literal_u32.as_u32;
fprintf(out, "" SV_FMT ":\n", SV_ARG(fn->id));
fprintf(out, " mov x0, #%d\n", exit_code);
fprintf(out, " ret\n");
}
|