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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_linux_x86_64.h"
#include "list.h"
#define SYS_exit (60)
static void
codegen_linux_x86_64_emit_start_entrypoint(FILE *out);
static void
codegen_linux_x86_64_emit_function(FILE *out, ast_fn_definition_t *fn);
void
codegen_linux_x86_64_emit_program(FILE *out, ast_node_t *node)
{
codegen_linux_x86_64_emit_start_entrypoint(out);
assert(node->kind == AST_NODE_PROGRAM);
ast_program_t program = node->data.as_program;
ast_fn_definition_t fn = program.fn->data.as_fn_def;
assert(string_view_eq_to_cstr(fn.identifier, "main"));
codegen_linux_x86_64_emit_function(out, &fn);
}
static void
codegen_linux_x86_64_emit_start_entrypoint(FILE *out)
{
fprintf(out, ".text\n");
fprintf(out, ".globl _start\n\n");
fprintf(out, "_start:\n");
fprintf(out, " call main\n");
fprintf(out, " mov %%eax, %%edi\n");
fprintf(out, " mov $%d, %%eax\n", SYS_exit);
fprintf(out, " syscall\n");
}
static void
codegen_linux_x86_64_emit_expression(FILE *out, ast_node_t *expr_node)
{
switch (expr_node->kind) {
case AST_NODE_LITERAL: {
ast_literal_t literal_u32 = expr_node->data.as_literal;
assert(literal_u32.kind == AST_LITERAL_U32);
uint32_t exit_code = literal_u32.value.as_u32;
fprintf(out, " mov $%d, %%eax\n", exit_code);
return;
}
case AST_NODE_BINARY_OP:
default:
assert(0 && "NOT IMPLEMENTED");
}
}
static void
codegen_linux_x86_64_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->data.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->data.as_return_stmt;
ast_node_t *expr = return_stmt.data;
fprintf(out, "" SV_FMT ":\n", SV_ARG(fn->identifier));
codegen_linux_x86_64_emit_expression(out, expr);
fprintf(out, " ret\n");
}
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