From 8ed9aca755087d3ee9e50f4eb5791241ce1bcc09 Mon Sep 17 00:00:00 2001
From: tyfkda <tyfkda@gmail.com>
Date: Mon, 7 Oct 2024 16:16:22 +0900
Subject: [PATCH] Assume case/default follows a statemet

---
 src/cc/backend/codegen.c  | 2 ++
 src/cc/frontend/ast.c     | 1 +
 src/cc/frontend/ast.h     | 1 +
 src/cc/frontend/fe_misc.c | 8 +++++++-
 src/cc/frontend/parser.c  | 8 ++++++++
 src/wcc/gen_wasm.c        | 6 +++---
 src/wcc/traverse.c        | 1 +
 tests/valtest.c           | 7 +++++++
 8 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/cc/backend/codegen.c b/src/cc/backend/codegen.c
index cc64e5f2d..d524a74b8 100644
--- a/src/cc/backend/codegen.c
+++ b/src/cc/backend/codegen.c
@@ -22,6 +22,7 @@
 static void gen_expr_stmt(Expr *expr);
 
 void set_curbb(BB *bb) {
+  assert(bb != NULL);
   assert(curfunc != NULL);
   if (curbb != NULL)
     curbb->next = bb;
@@ -510,6 +511,7 @@ static void gen_switch(Stmt *stmt) {
 
 inline void gen_case(Stmt *stmt) {
   set_curbb(stmt->case_.bb);
+  gen_stmt(stmt->case_.stmt);
 }
 
 static void gen_while(Stmt *stmt) {
diff --git a/src/cc/frontend/ast.c b/src/cc/frontend/ast.c
index b2d52d5ad..f95e7d4d1 100644
--- a/src/cc/frontend/ast.c
+++ b/src/cc/frontend/ast.c
@@ -265,6 +265,7 @@ Stmt *new_stmt_case(const Token *token, Stmt *swtch, Expr *value) {
   Stmt *stmt = new_stmt(ST_CASE, token);
   stmt->case_.swtch = swtch;
   stmt->case_.value = value;
+  stmt->case_.stmt = NULL;
   stmt->case_.bb = NULL;
   return stmt;
 }
diff --git a/src/cc/frontend/ast.h b/src/cc/frontend/ast.h
index 4aab53603..7da45ea6f 100644
--- a/src/cc/frontend/ast.h
+++ b/src/cc/frontend/ast.h
@@ -398,6 +398,7 @@ typedef struct Stmt {
     struct {
       struct Stmt *swtch;
       Expr *value;  // NULL => default
+      struct Stmt *stmt;
       //
       BB *bb;
     } case_;
diff --git a/src/cc/frontend/fe_misc.c b/src/cc/frontend/fe_misc.c
index 6ae730aaa..f41209e35 100644
--- a/src/cc/frontend/fe_misc.c
+++ b/src/cc/frontend/fe_misc.c
@@ -1558,6 +1558,10 @@ static void check_reachability_stmt(Stmt *stmt) {
     stmt->break_.parent->reach &= ~REACH_STOP;
     stmt->reach |= REACH_STOP;
     break;
+  case ST_CASE:
+    check_reachability_stmt(stmt->case_.stmt);
+    stmt->reach = stmt->case_.stmt->reach;
+    break;
   case ST_GOTO:
     // TODO:
     stmt->reach |= REACH_STOP;
@@ -1585,7 +1589,7 @@ static void check_reachability_stmt(Stmt *stmt) {
       }
     }
     break;
-  case ST_EMPTY: case ST_CASE: case ST_VARDECL: case ST_ASM:
+  case ST_EMPTY: case ST_VARDECL: case ST_ASM:
     stmt->reach = 0;
     break;
   }
@@ -1968,6 +1972,8 @@ static Stmt *duplicate_inline_function_stmt(Function *targetfunc, Scope *targets
         // Value is constant so reuse.
         assert(is_const(stmt->case_.value));
       }
+      dup->case_.stmt = duplicate_inline_function_stmt(targetfunc, targetscope, stmt->case_.stmt);
+
       // Find index.
       Stmt *org_swtch = stmt->case_.swtch;
       Vector *org_cases = org_swtch->switch_.cases;
diff --git a/src/cc/frontend/parser.c b/src/cc/frontend/parser.c
index f13775bb0..61aa77aa0 100644
--- a/src/cc/frontend/parser.c
+++ b/src/cc/frontend/parser.c
@@ -351,6 +351,14 @@ static Stmt *parse_case(const Token *tok) {
   vec_push(swtch->switch_.cases, stmt);
   if (tok->kind == TK_DEFAULT)
     swtch->switch_.default_ = stmt;
+
+  Stmt *next = parse_stmt();
+  if (next == NULL) {
+    parse_error(PE_NOFATAL, tok, "statement expected");
+    next = new_stmt(ST_EMPTY, tok);  // Dummy
+  }
+  stmt->case_.stmt = next;
+
   return stmt;
 }
 
diff --git a/src/wcc/gen_wasm.c b/src/wcc/gen_wasm.c
index 0f79561e6..87b2e889d 100644
--- a/src/wcc/gen_wasm.c
+++ b/src/wcc/gen_wasm.c
@@ -1202,11 +1202,11 @@ static void gen_switch(Stmt *stmt) {
   break_depth = save_depth;
 }
 
-static void gen_case(Stmt *stmt) {
-  UNUSED(stmt);
+static void gen_case(Stmt *stmt, bool is_last) {
   ADD_CODE(OP_END);
   --cur_depth;
   assert(cur_depth >= 0);
+  gen_stmt(stmt->case_.stmt, is_last);
 }
 
 static void gen_while(Stmt *stmt) {
@@ -1445,7 +1445,7 @@ static void gen_stmt(Stmt *stmt, bool is_last) {
   case ST_BLOCK:  gen_block(stmt, is_last); break;
   case ST_IF:  gen_if(stmt, is_last); break;
   case ST_SWITCH:  gen_switch(stmt); break;
-  case ST_CASE:  gen_case(stmt); break;
+  case ST_CASE:  gen_case(stmt, is_last); break;
   case ST_WHILE:  gen_while(stmt); break;
   case ST_DO_WHILE:  gen_do_while(stmt); break;
   case ST_FOR:  gen_for(stmt); break;
diff --git a/src/wcc/traverse.c b/src/wcc/traverse.c
index 38258349e..07cc242bc 100644
--- a/src/wcc/traverse.c
+++ b/src/wcc/traverse.c
@@ -591,6 +591,7 @@ static void traverse_switch(Stmt *stmt) {
 static void traverse_case(Stmt *stmt) {
   if (branching_stmt->kind != ST_SWITCH)
     parse_error(PE_FATAL, stmt->token, "case/default inside branch not supported");
+  traverse_stmt(stmt->case_.stmt);
 }
 
 static void traverse_while(Stmt *stmt) {
diff --git a/tests/valtest.c b/tests/valtest.c
index 2112e71cb..5c9fc112c 100644
--- a/tests/valtest.c
+++ b/tests/valtest.c
@@ -425,6 +425,13 @@ TEST(all) {
     }
     EXPECT("switch fallthrough", 11, x);
   }
+  {
+    int x = 44;
+    switch (x)
+      case 1:
+        x = 55;
+    EXPECT("switch w/o bracket", 44, x);
+  }
   {
     int x = 10, *p = &x;
     ++(*p);