Compiler: force zero initialization of local variables

ast/ast_evaluator.c2

@@ -281,17 +281,17 @@ fn Value Evaluator.eval_call(Evaluator* caller, const CallExpr* c) {
 
     // Create a new stack frame and link it to the caller's
     // TODO: handle Stack frames as separate allocated objects
-    Evaluator eval;
-
-    if (num_args > elemsof(eval.args)) {
-        return Value.error("too many arguments in pure function evaluation");
-    }
+    Evaluator eval /*@(noinit)*/;
     eval.prev = caller;
     eval.fd = fd;
     eval.num_args = num_args;
     eval.depth = caller.depth + 1;
     eval.complexity = caller.complexity + 1;
 
+    if (num_args > elemsof(eval.args)) {
+        return Value.error("too many arguments in pure function evaluation");
+    }
+
     //VarDecl** params = fd.getParams();
 
     for (u32 i = 0; i < num_args; i++) {

ast/value.c2

@@ -799,7 +799,7 @@ fn f64 fabs(f64 d) {
 // string and trying to avoid using exponential notation
 // TODO: should be in the C2 library as a type function f64.str()
 public fn char *ftoa(char *dest, usize size, f64 d) {
-    char[32] buf;
+    char[32] buf /*@(noinit)*/;
     usize pos = 0;
 
     if (size < 2) {

ast/var_decl.c2

@@ -51,6 +51,7 @@ type VarDeclBits struct {
     u32 has_init_call : 1; // local variables only
     u32 attr_weak : 1; // globals only
     u32 addr_used : 1;
+    u32 attr_noinit : 1;
     u32 auto_attr : 2;  // AutoAttr, for parameters only
     u32 printf_format : 1; // for parameters only
 }
@@ -301,6 +302,14 @@ public fn bool VarDecl.hasInitCall(const VarDecl* d) {
     return d.base.varDeclBits.has_init_call;
 }
 
+public fn void VarDecl.setAttrNoInit(VarDecl* d) {
+    d.base.varDeclBits.attr_noinit = 1;
+}
+
+public fn bool VarDecl.hasAttrNoInit(const VarDecl* d) {
+    return d.base.varDeclBits.attr_noinit;
+}
+
 public fn void VarDecl.setAttrWeak(VarDecl* d) {
     d.base.varDeclBits.attr_weak = 1;
 }

ast_utils/attr.c2

@@ -42,6 +42,7 @@ public type AttrKind enum u8 {
     AutoLine,       //               Var, function param only
     AutoFunc,       //               Var, function param only
     Embed,          //               Var, globals only
+    NoInit,         //               Var
 }
 
 const char*[] attrKind_names = {
@@ -67,6 +68,7 @@ const char*[] attrKind_names = {
     "auto_line",
     "auto_func",
     "embed",
+    "noinit",
 }
 
 static_assert(elemsof(AttrKind), elemsof(attrKind_names));
@@ -146,6 +148,7 @@ const AttrReq[] Required_arg = {
     [AttrKind.AutoLine]     = AttrReq.NoArg,
     [AttrKind.AutoFunc]     = AttrReq.NoArg,
     [AttrKind.Embed]        = AttrReq.String,
+    [AttrKind.NoInit]       = AttrReq.NoArg,
 }
 static_assert(elemsof(AttrKind), elemsof(Required_arg));
 

ast_utils/string_buffer.c2

@@ -167,7 +167,7 @@ public fn void Buf.stripTrailingSpaces(Buf* buf) {
 }
 
 public fn void Buf.print(Buf* buf, const char* format @(printf_format), ...) {
-    char[4096] tmp;
+    char[4096] tmp /*@(noinit)*/;
     // NOTE: no growing
     va_list args;
     va_start(args, format);
@@ -178,7 +178,7 @@ public fn void Buf.print(Buf* buf, const char* format @(printf_format), ...) {
 }
 
 public fn void Buf.vprintf(Buf* buf, const char* format, va_list args) {
-    char[4096] tmp;
+    char[4096] tmp /*@(noinit)*/;
     // NOTE: no growing
     i32 len = vsnprintf(tmp, sizeof(tmp), format, args);
     assert(len < sizeof(tmp));

common/ast_builder.c2

@@ -512,6 +512,9 @@ fn void Builder.actOnVarAttr(Builder* b, Decl* d, const Attr* a) {
     case Embed:
         b.storeAttr(d, a);
         break;
+    case NoInit:
+        vd.setAttrNoInit();
+        break;
     default:
         b.diags.error(a.loc, "attribute '%s' is not applicable to variables",
                 kind2name(a.kind));

common/file/file_utils.c2

@@ -116,7 +116,7 @@ public fn const char* make_path3(char *buf, usize size, const char* dir, const c
 // returns 0 on success, errno on failure
 // create a directory path, OK if exists already
 public fn i32 create_path(const char* path) {
-    char[file_utils.Max_path] tmp;
+    char[file_utils.Max_path] tmp /*@(noinit)*/;
     char *p = tmp;
     if (!*path) return 0;
     *p++ = *path++;

generator/c/c_generator.c2

@@ -1280,8 +1280,7 @@ public fn void generate(string_pool.Pool* astPool,
         return;
     }
 
-    Generator gen;
-    gen.init(astPool, target, kind, output_dir, dir, diags, sm, build_info, mainFunc);
+    Generator gen.init(astPool, target, kind, output_dir, dir, diags, sm, build_info, mainFunc);
     gen.auxPool = auxPool;
     gen.enable_asserts = enable_asserts;
     gen.fast_build = fast_build;

generator/c/c_generator_special.c2

@@ -62,7 +62,7 @@ fn void Generator.createMakefile(Generator* gen,
     out.print("CC=%s\n", cc);
 
     out.add("CFLAGS=-Wall -Wextra -Wno-unused -Wno-switch\n");
-    out.add("CFLAGS+=-Wno-unused-parameter -Wno-missing-field-initializers -Wno-format-zero-length\n");
+    out.add("CFLAGS+=-Wno-unused-parameter -Wno-missing-field-initializers -Wno-missing-braces -Wno-format-zero-length\n");
     out.add("CFLAGS+=-pipe -std=c99 -funsigned-char\n");
     if (gen.fast_build)
         out.add("CFLAGS+=-O0 -g\n");

generator/c/c_generator_stmt.c2

@@ -40,6 +40,10 @@ fn void Generator.emitVarDecl(Generator* gen, VarDecl* vd, string_buffer.Buf* ou
             out.add(" = ");
         }
         gen.emitExpr(out, ie);
+    } else {
+        if (!vd.hasAttrNoInit()) {
+            out.add(" = { 0 }");
+        }
     }
 }
 

parser/c2_parser.c2

@@ -370,7 +370,10 @@ fn void Parser.parseTopLevel(Parser* p) {
 
 // returns if embed attribute was seen
 fn void Parser.parseOptionalAttributes(Parser* p) {
-    if (p.tok.kind != Kind.At) return;
+    if (p.tok.kind == Kind.At) p.parseAttributes();
+}
+
+fn void Parser.parseAttributes(Parser* p) {
     p.consumeToken();
 
     p.expectAndConsume(Kind.LParen);

parser/c2_parser_stmt.c2

@@ -21,6 +21,7 @@ import constants local;
 import token local;
 import src_loc local;
 import string_list;
+import string local;
 
 fn Stmt* Parser.parseStmt(Parser* p) {
     // TODO use Jump Table (combined one for multiple purposes?)
@@ -516,7 +517,7 @@ fn Stmt* Parser.parseWhileStmt(Parser* p) {
 }
 
 fn Stmt* Parser.parseDeclStmt(Parser* p, bool checkSemi, bool allowLocal, bool isCondition) {
-    VarDecl*[MaxMultiDecl] decls;
+    VarDecl*[MaxMultiDecl] decls /*@(noinit)*/;
     u32 num_decls = 0;
     bool has_local = false;
     if (p.tok.kind == Kind.KW_local) {
@@ -541,6 +542,7 @@ fn Stmt* Parser.parseDeclStmt(Parser* p, bool checkSemi, bool allowLocal, bool i
         p.consumeToken();
 
         // TODO same as parseVarDecl()
+        bool has_noinit = false;
         bool has_init_call = false;
         need_semi = true;
         Expr* initValue = nil;
@@ -555,7 +557,14 @@ fn Stmt* Parser.parseDeclStmt(Parser* p, bool checkSemi, bool allowLocal, bool i
             need_semi = checkSemi && initValue.needsSemi();
             break;
         case At:
-            p.error("local variables cannot have attributes");
+            // check for noinit attribute
+            p.consumeToken();
+            p.expectAndConsume(Kind.LParen);
+            p.expectIdentifier();
+            if (strcmp(p.pool.idx2str(p.tok.name_idx), "noinit"))
+                p.error("local variables cannot have attributes");
+            has_noinit = true;
+            p.expectAndConsume(Kind.RParen);
             break;
         case Dot:
             if (p.peekToken(1) == Kind.Identifier
@@ -583,7 +592,9 @@ fn Stmt* Parser.parseDeclStmt(Parser* p, bool checkSemi, bool allowLocal, bool i
         default:
             break;
         }
-        decls[num_decls++] = p.builder.actOnVarDecl(name, loc, &ref, assignLoc, initValue, has_local, has_init_call);
+        VarDecl* vd = p.builder.actOnVarDecl(name, loc, &ref, assignLoc, initValue, has_local, has_init_call);
+        if (has_noinit) vd.setAttrNoInit();
+        decls[num_decls++] = vd;
         if (p.tok.kind != Kind.Comma)
             break;
         p.consumeToken();

parser/c2_tokenizer.c2

@@ -888,7 +888,7 @@ check_overflow:
 }
 
 fn void Tokenizer.lex_floating_point(Tokenizer* t, Token* result, const char* start) {
-    char[4096] buf;
+    char[128] buf /*@(noinit)*/;
     const char* p = start;
     usize pos = 0;
     u8 seen_dot = 0;
@@ -939,7 +939,7 @@ too_large:
 }
 
 fn void Tokenizer.lex_floating_point_hex(Tokenizer* t, Token* result, const char* start) {
-    char[4096] buf;
+    char[128] buf /*@(noinit)*/;
     const char* p = start;
     usize pos = 0;
     u8 seen_dot = 0;

test/auto_args/struct_function_before_self.c2t

@@ -27,7 +27,7 @@ static void test_Foo_test(const char* file, uint32_t line, test_Foo* f, void* p)
 
 int32_t main(void)
 {
-   test_Foo f;
+   test_Foo f = { 0 };
    test_Foo_test("file1.c2", 11, &f, NULL);
    return 0;
 }

test/auto_args/struct_function_ok.c2t

@@ -27,7 +27,7 @@ static void test_Foo_test(test_Foo* f, const char* file, uint32_t line, void* p)
 
 int32_t main(void)
 {
-   test_Foo f;
+   test_Foo f = { 0 };
    test_Foo_test(&f, "file1.c2", 11, NULL);
    test_Foo_test(&f, "file1.c2", 12, NULL);
    return 0;

test/c_generator/asm/gen_asm.c2t

@@ -48,16 +48,16 @@ static void test_basic_asm(void);
 
 static int32_t test_add(int32_t x, int32_t y)
 {
-  int32_t result;
+    int32_t result = { 0 };
   __asm__ volatile ("add %[Rd], %[Rm], %[Rn]" : [Rd] "=r" (result) : [Rm] "r" (x), [Rn] "r" (y));
   return result;
 }
 
 static void test_clobbers(void)
 {
-  int32_t from;
-  int32_t to;
-  int32_t count;
+  int32_t from = { 0 };
+  int32_t to = { 0 };
+  int32_t count = { 0 };
   __asm__ volatile ("movc3 %0, %1, %2"
             :
             : "g" (from), "g" (to), "g" (count)
@@ -67,8 +67,8 @@ static void test_clobbers(void)
 static inline
 uint64_t test_rdtsc(void)
 {
-  uint32_t lo;
-  uint32_t hi;
+  uint32_t lo = { 0 };
+  uint32_t hi = { 0 };
   __asm__ volatile ("rdtsc" : "=a" (lo), "=d" (hi));
   uint64_t res = hi;
   res <<= 32;

test/c_generator/expr/prec_expr.c2t

@@ -30,7 +30,7 @@ public fn i32 main(i32 argc, const char** argv) {
 
 int32_t main(int32_t argc, const char** argv)
 {
-    int32_t a;
+    int32_t a = { 0 };
 
     a = (1 << 2) + 3;
     a = ((1 ^ 2) | 3) & 4;

test/c_generator/functions/inline/inline_prefix.c2t

@@ -47,7 +47,7 @@ type Point struct {
 static inline
 void test1_myfunc(const test2_Point* p)
 {
-  test2_Point points[3];
+  test2_Point points[3] = { 0 };
   points[1] = *p;
 }
 

test/c_generator/functions/inline/inline_stmts.c2t

@@ -114,7 +114,7 @@ next:
 static inline
 int32_t test1_test_fn(const char* format, ...)
 {
-  const char* p;
+  const char* p = { 0 };
   {
     const char* q = format;
     if (q) {
@@ -137,7 +137,7 @@ int32_t test1_test_fn(const char* format, ...)
   if (format) p = format;
   else p = format;
   {
-    const char* q;
+    const char* q = { 0 };
     while ((q = format)) {
     }
   }

test/c_generator/functions/inline/lib_public_inline.c2t

@@ -41,7 +41,7 @@ typedef void (*test1_Handler)(int32_t* _arg0);
 static inline
 int32_t test1_test_fn(test1_Handler a, int32_t** b)
 {
-  int32_t c[4];
+  int32_t c[4] = { 0 };
   a(*b);
   return 123;
 }

test/c_generator/functions/inline/nonpublic_inline.c2t

@@ -42,6 +42,6 @@ void test1_test_fn(void)
 {
    test1_non_public();
    test1_num++;
-   test1_Priv p;
+   test1_Priv p = { 0 };
    test1_Handler h = test1_non_public;
 }

test/c_generator/functions/struct_functions/chained_struct_calls.c2t

@@ -73,7 +73,7 @@ static test_B* test_C_getB(test_C* c)
 
 static void test_test1(void)
 {
-  test_C c;
+  test_C c = { 0 };
   uint32_t n = test_A_run(test_B_getA(test_C_getB(&c)));
 }
 

test/c_generator/functions/struct_functions/local.c2t

@@ -33,7 +33,7 @@ static void test_Type_init(test_Type* _arg0)
 
 int32_t main(void)
 {
-  test_Type t;
+  test_Type t = { 0 };
   test_Type_init(&t);
   return 0;
 }

test/c_generator/functions/struct_functions/local_arg.c2t

@@ -33,7 +33,7 @@ static void test_Type_init(test_Type* _arg0, int32_t _arg1)
 
 int32_t main(void)
 {
-  test_Type t;
+  test_Type t = { 0 };
   test_Type_init(&t, 4);
   return 0;
 }

test/c_generator/functions/struct_functions/local_member.c2t

@@ -31,7 +31,7 @@ static void test_Type_init(test_Type* _arg0)
 
 int32_t main(void)
 {
-  test_Outer o;
+  test_Outer o = { 0 };
   test_Type_init(&o.t);
   return 0;
 }

test/c_generator/functions/struct_functions/local_normal_callback.c2t

@@ -28,7 +28,7 @@ struct test_Type_ {
 
 int32_t main(void)
 {
-  test_Type t;
+  test_Type t = { 0 };
   t.init(1);
   return 0;
 }

test/c_generator/functions/struct_functions/local_ptr.c2t

@@ -33,7 +33,7 @@ static void test_Type_init(test_Type* _arg0)
 
 int32_t main(void)
 {
-  test_Type* t;
+  test_Type* t = { 0 };
   test_Type_init(t);
   return 0;
 }

test/c_generator/stmts/local_array_decl.c2t

@@ -26,6 +26,6 @@ static void test_func1(void);
 
 static void test_func1(void)
 {
-  int32_t board2[20][20];
+  int32_t board2[20][20] = { 0 };
 }