Merge pull request #55 from Vipon/vkonyche_msvc_mode_code_workaround

Create MSVC workaround for MOD_CODE. issue: #52
Vipon · Feb 24, 2024 · c666876 · c666876
2 parents 4650a5b + 94c9632
commit c666876
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Showing 3 changed files with 26 additions and 16 deletions.
diff --git a/cTools/libs/mod/mod_code/CMakeLists.txt b/cTools/libs/mod/mod_code/CMakeLists.txt
@@ -37,9 +37,5 @@ add_vipon_library(
   INSTALL ON
 )
 
-# MSVC compiler wrongly works with inline assembler. MSVC emits a lot of "int3"
-# instructions if there is a ".section" directive.
-if (NOT MSVC)
-  add_subdirectory(test)
-endif ()
+add_subdirectory(test)
 
diff --git a/cTools/libs/mod/mod_code/mod_code.h b/cTools/libs/mod/mod_code/mod_code.h
@@ -72,6 +72,20 @@
     "r8", "r9", "r10", "r11",    \
     "r12", "r13", "r14", "r15"
 
+#ifdef _MSC_VER
+// Works without __builtin_expect also.
+// Code generated more redable with __builtin_expect.
+# define MSVC_WORKAROUND(code)              \
+    {                                       \
+        volatile static int a = 1;          \
+        if (__builtin_expect(a == 0, 0)) {  \
+            code;                           \
+        }                                   \
+    }
+#else /* _MSVC_LANG */
+# define MSVC_WORKAROUND(code) code
+#endif /* _MSVC_LANG */
+
 #if AARCH64_DEFINED == 1
 # define MOD_CODE(code)                                             \
     DEF_GUARD(                                                      \
@@ -108,6 +122,10 @@
     DEF_GUARD(                                                      \
         ASM volatile(                                               \
         "0:\n"                                                      \
+        ::: "memory", CLOBBERS_ALL_X86_64_REGS                      \
+        );                                                          \
+        MSVC_WORKAROUND(                                            \
+        ASM volatile(                                               \
         PUSHSECTION" "MC_STRUCT_SEGSECT", "MOD_SECT_FLAGS"\n"       \
             ".align 8\n"                                            \
             /* .insert_point */                                     \
@@ -131,6 +149,7 @@
         POPSECTION"\n"                                              \
         ::: "memory", CLOBBERS_ALL_X86_64_REGS                      \
         );                                                          \
+        );                                                          \
     )
 #else
 # error "Unknown machine type"

diff --git a/cTools/libs/mod/mod_code/test/mod_code_test.c b/cTools/libs/mod/mod_code/test/mod_code_test.c
@@ -26,27 +26,22 @@
 #include "mod_code.h"
 #include <inttypes.h>
 
-extern void test_func(void);
+extern void test_func(void) __attribute__((noinline));
 void test_func(void)
 {
+    MOD_CODE(
+        printf("hello\n");
+    );
+
     STDERROR_PRINT("I'm here\n");
 }
 
-extern volatile int a;
-volatile int a = 0;
-
 int main(int argc, const char *argv[])
 {
     UNUSED(argc);
     UNUSED(argv);
 
-    STDERROR_PRINT("main: %p\n", (void*)&main);
-
-    MOD_CODE(
-        do {
-            printf("hello\n");
-        } while (a);
-    );
+    STDERROR_PRINT("test_func: %p\n", (void*)&test_func);
 
     mod_code_init(argv[0]);
     mod_code_dump();