[libc-commits] [libc] [libc][i386] setjmp/longjmp (PR #112437)

[Nick Desaulniers via libc-commits]

================
@@ -7,15 +7,34 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/setjmp/longjmp.h"
+#include "include/llvm-libc-macros/offsetof-macro.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
 
-#if !defined(LIBC_TARGET_ARCH_IS_X86_64)
+#if !defined(LIBC_TARGET_ARCH_IS_X86)
 #error "Invalid file include"
 #endif
 
 namespace LIBC_NAMESPACE_DECL {
 
+#ifdef __i386__
+[[noreturn]]
+LLVM_LIBC_FUNCTION(void, longjmp, (jmp_buf buf, int val)) {
+  asm(R"(
----------------
nickdesaulniers wrote:

> but I don't think you can validly clobber ebp/esp

You can.

```diff
diff --git a/libc/src/setjmp/x86_64/setjmp.cpp b/libc/src/setjmp/x86_64/setjmp.cpp
index 90532c5654b3..b47db5c63e18 100644
--- a/libc/src/setjmp/x86_64/setjmp.cpp
+++ b/libc/src/setjmp/x86_64/setjmp.cpp
@@ -42,7 +42,7 @@ LLVM_LIBC_FUNCTION(int, setjmp, (jmp_buf buf)) {
       [ebp] "i"(offsetof(__jmp_buf, ebp)),
       [esp] "i"(offsetof(__jmp_buf, esp)),
       [eip] "i"(offsetof(__jmp_buf, eip))
-      : "eax", "ecx");
+      : "eax", "ecx", "ebx", "esi", "edi", "ebp", "esp");
 }
 #else
 [[gnu::naked]]
```

compiles just fine.

https://github.com/llvm/llvm-project/pull/112437