macos: Fix asm-c-connect-test

via some heavy-handed hackery in the ASM symbol handling in case
C symbols get a leading underscore (but ASM symbols do not).
But this is now like clang and GCC on Darwin work: asm symbols are
undecorated, C symbols get a _ prepended, so to connect both some
trickery is involved for the ASM symbols that don't have a _ prepended.
They must be included in the C symbol table (because that's what we use
to lookup also ASM labels), but they also must not disturb the normal
C symbol (which don't have the _ prepended), so they need some mangling.

A bit unsatisfying, but well.  So, add asm-c-connect-test to the working
ones for Darwin as well.

i386-asm.c

@@ -1490,6 +1490,8 @@ ST_FUNC void subst_asm_operand(CString *add_str,
 		   list when we still know the symbol.  */
 		get_asm_sym(tok_alloc(name, strlen(name))->tok, sv->sym);
 	    }
+            if (tcc_state->leading_underscore)
+              cstr_ccat(add_str, '_');
             cstr_cat(add_str, name, -1);
             if ((uint32_t)sv->c.i == 0)
                 goto no_offset;

lib/alloca86_64-bt.S

@@ -4,6 +4,7 @@
 #ifdef __APPLE__
 #define __bound_alloca ___bound_alloca
 #define __bound_alloca_nr ___bound_alloca_nr
+#define __bound_new_region ___bound_new_region
 #endif
 
 .globl __bound_alloca

tccasm.c

@@ -38,9 +38,39 @@ static int tcc_assemble_internal(TCCState *s1, int do_preprocess, int global);
 static Sym* asm_new_label(TCCState *s1, int label, int is_local);
 static Sym* asm_new_label1(TCCState *s1, int label, int is_local, int sh_num, int value);
 
+/* If a C name has an _ prepended then only asm labels that start
+   with _ are representable in C, by removing the first _.  ASM names
+   without _ at the beginning don't correspond to C names, but we use
+   the global C symbol table to track ASM names as well, so we need to
+   transform those into ones that don't conflict with a C name,
+   so prepend a '.' for them, but force the ELF asm name to be set.  */
+static int asm2cname(int v, int *addeddot)
+{
+    const char *name;
+    *addeddot = 0;
+    if (!tcc_state->leading_underscore)
+      return v;
+    name = get_tok_str(v, NULL);
+    if (!name)
+      return v;
+    if (name[0] == '_') {
+        v = tok_alloc(name + 1, strlen(name) - 1)->tok;
+    } else if (!strchr(name, '.')) {
+        int n = strlen(name) + 2;
+        char newname[n];
+        snprintf(newname, n, ".%s", name);
+        v = tok_alloc(newname, n - 1)->tok;
+        *addeddot = 1;
+    }
+    return v;
+}
+
 static Sym *asm_label_find(int v)
 {
-    Sym *sym = sym_find(v);
+    Sym *sym;
+    int addeddot;
+    v = asm2cname(v, &addeddot);
+    sym = sym_find(v);
     while (sym && sym->sym_scope && !(sym->type.t & VT_STATIC))
         sym = sym->prev_tok;
     return sym;
@@ -48,10 +78,14 @@ static Sym *asm_label_find(int v)
 
 static Sym *asm_label_push(int v)
 {
+    int addeddot, v2 = asm2cname(v, &addeddot);
     /* We always add VT_EXTERN, for sym definition that's tentative
        (for .set, removed for real defs), for mere references it's correct
        as is.  */
-    return global_identifier_push(v, VT_ASM | VT_EXTERN | VT_STATIC, 0);
+    Sym *sym = global_identifier_push(v2, VT_ASM | VT_EXTERN | VT_STATIC, 0);
+    if (addeddot)
+        sym->asm_label = v;
+    return sym;
 }
 
 /* Return a symbol we can use inside the assembler, having name NAME.
@@ -390,7 +424,7 @@ static Sym* asm_new_label1(TCCState *s1, int label, int is_local,
         sym = asm_label_push(label);
     }
     if (!sym->c)
-      put_extern_sym2(sym, SHN_UNDEF, 0, 0, 0);
+      put_extern_sym2(sym, SHN_UNDEF, 0, 0, 1);
     esym = elfsym(sym);
     esym->st_shndx = sh_num;
     esym->st_value = value;

tests/Makefile

@@ -46,7 +46,7 @@ ifeq ($(ARCH),riscv64)
 endif
 endif
 ifdef CONFIG_OSX # some don't work yet
- TESTS := $(filter-out memtest dlltest asm-c-connect-test, $(TESTS))
+ TESTS := $(filter-out memtest dlltest, $(TESTS))
 endif
 ifeq (,$(filter arm64 i386 x86_64,$(ARCH)))
  TESTS := $(filter-out vla_test-run,$(TESTS))

tests/asm-c-connect-1.c

@@ -2,11 +2,20 @@
 
 #if defined _WIN32 && !defined __TINYC__
 # define _ "_"
+#elif defined __APPLE__
+# define _ "_"
 #else
 # define _
 #endif
 
-static int x1_c(void)
+#ifdef __clang__
+/* clang needs some help tp not throw functions away even at -O0 */
+#define __USED __attribute__((__used__))
+#else
+#define __USED
+#endif
+
+static int __USED x1_c (void)
 {
     printf(" x1");
     return 1;
@@ -37,7 +46,7 @@ int main(int argc, char *argv[])
 }
 
 static
-int x2(void)
+int __USED x2(void)
 {
     printf(" x2");
     return 2;

tests/asm-c-connect-2.c

@@ -2,10 +2,19 @@
 
 #if defined _WIN32 && !defined __TINYC__
 # define _ "_"
+#elif defined __APPLE__
+# define _ "_"
 #else
 # define _
 #endif
 
+#ifdef __clang__
+/* clang needs some help tp not throw functions away even at -O0 */
+#define __USED __attribute__((__used__))
+#else
+#define __USED
+#endif
+
 int x3(void)
 {
     printf(" x3");
@@ -30,7 +39,7 @@ void callx5_again(void)
     asm("call "_"x6");
 }
 
-static void x6()
+static void __USED x6()
 {
     printf(" x6-2");
 }

tests/tcctest.c

@@ -3650,7 +3650,7 @@ void test_asm_call(void)
   asm volatile ("push %%rdi; push %%rdi; mov %0, %%rdi;"
 #if 1 && !defined(__TINYC__) && (defined(__PIC__) || defined(__PIE__)) && !defined(__APPLE__)
 		"call getenv@plt;"
-#elif defined(__APPLE__) && !defined(__TINYC__)
+#elif defined(__APPLE__)
                 "call _getenv;"
 #else
 		"call getenv;"

tests/tests2/85_asm-outside-function.c

@@ -1,6 +1,11 @@
+#ifdef __APPLE__
+#define _ "_"
+#else
+#define _
+#endif
 extern int printf (const char *, ...);
 extern void vide(void);
-__asm__("vide: ret");
+__asm__(_"vide: ret");
 
 int main() {
     vide();