1 files changed, 119 insertions, 0 deletions
diff --git a/src/codegen_wasm.c b/src/codegen_wasm.c
new file mode 100644
index 0000000..1072b67
--- /dev/null
+++ b/src/codegen_wasm.c
@@ -0,0 +1,119 @@
+#include <stdlib.h>
+#include <string.h>
+#include "codegen.h"
+#include "common.h"
+#include "preprocess.h"
+
+typedef enum {
+    GenMode_lval,
+    GenMode_rval,
+} GenMode;
+
+typedef struct {
+    FILE* out;
+    int next_label;
+    int* loop_labels;
+    AstNode* current_func;
+    int switch_label;
+} CodeGen;
+
+static CodeGen* codegen_new(FILE* out) {
+    CodeGen* g = calloc(1, sizeof(CodeGen));
+    g->out = out;
+    g->next_label = 1;
+    g->loop_labels = calloc(1024, sizeof(int));
+    g->switch_label = -1;
+    return g;
+}
+
+static void codegen_expr(CodeGen* g, AstNode* ast, GenMode gen_mode);
+static void codegen_stmt(CodeGen* g, AstNode* ast);
+
+static void codegen_func_prologue(CodeGen* g, AstNode* ast) {
+    for (int i = 0; i < ast->node_params->node_len; ++i) {
+        fprintf(g->out, " (param $l_%s i32)", ast->node_params->node_items[i].name);
+    }
+    fprintf(g->out, " (result i32)\n");
+}
+
+static void codegen_func_epilogue(CodeGen* g, AstNode* ast) {
+}
+
+static void codegen_binary_expr(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+    codegen_expr(g, ast->node_lhs, gen_mode);
+    codegen_expr(g, ast->node_rhs, gen_mode);
+    if (ast->node_op == TokenKind_plus) {
+        fprintf(g->out, "i32.add\n");
+    } else {
+        unreachable();
+    }
+}
+
+static void codegen_lvar(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+    fprintf(g->out, "  local.get $l_%s\n", ast->name);
+}
+
+static void codegen_expr(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+    if (ast->kind == AstNodeKind_binary_expr) {
+        codegen_binary_expr(g, ast, gen_mode);
+    } else if (ast->kind == AstNodeKind_lvar) {
+        codegen_lvar(g, ast, gen_mode);
+    } else {
+        unreachable();
+    }
+}
+
+static void codegen_return_stmt(CodeGen* g, AstNode* ast) {
+    if (ast->node_expr) {
+        codegen_expr(g, ast->node_expr, GenMode_rval);
+    }
+    codegen_func_epilogue(g, ast);
+}
+
+static void codegen_nop(CodeGen* g, AstNode* ast) {
+}
+
+static void codegen_block_stmt(CodeGen* g, AstNode* ast) {
+    for (int i = 0; i < ast->node_len; ++i) {
+        AstNode* stmt = ast->node_items + i;
+        codegen_stmt(g, stmt);
+    }
+}
+
+static void codegen_stmt(CodeGen* g, AstNode* ast) {
+    if (ast->kind == AstNodeKind_list) {
+        codegen_block_stmt(g, ast);
+    } else if (ast->kind == AstNodeKind_return_stmt) {
+        codegen_return_stmt(g, ast);
+    } else if (ast->kind == AstNodeKind_nop) {
+        codegen_nop(g, ast);
+    } else {
+        unreachable();
+    }
+}
+
+static void codegen_func(CodeGen* g, AstNode* ast) {
+    g->current_func = ast;
+
+    fprintf(g->out, "(func (export \"%s\") \n", ast->name);
+
+    codegen_func_prologue(g, ast);
+    codegen_stmt(g, ast->node_body);
+    codegen_func_epilogue(g, ast);
+
+    fprintf(g->out, ")\n");
+    g->current_func = NULL;
+}
+
+void codegen_wasm(Program* prog, FILE* out) {
+    CodeGen* g = codegen_new(out);
+
+    fprintf(g->out, "(module\n");
+
+    for (int i = 0; i < prog->funcs->node_len; ++i) {
+        AstNode* func = prog->funcs->node_items + i;
+        codegen_func(g, func);
+    }
+
+    fprintf(g->out, ")\n");
+}