[libc-commits] [libc] b1320d3 - [libc][i386] setjmp/longjmp (#112437)

[via libc-commits]

Author: Nick Desaulniers
Date: 2024-10-30T12:59:59-07:00
New Revision: b1320d36339e38b073088fd45013a3c692adb301

URL: https://github.com/llvm/llvm-project/commit/b1320d36339e38b073088fd45013a3c692adb301
DIFF: https://github.com/llvm/llvm-project/commit/b1320d36339e38b073088fd45013a3c692adb301.diff

LOG: [libc][i386] setjmp/longjmp (#112437)

Link: #93709

Added: 
    

Modified: 
    libc/include/llvm-libc-types/jmp_buf.h
    libc/src/setjmp/x86_64/longjmp.cpp
    libc/src/setjmp/x86_64/setjmp.cpp

Removed: 
    


################################################################################
diff  --git a/libc/include/llvm-libc-types/jmp_buf.h b/libc/include/llvm-libc-types/jmp_buf.h
index 60e033c6c65a95..f246e6491cf554 100644
--- a/libc/include/llvm-libc-types/jmp_buf.h
+++ b/libc/include/llvm-libc-types/jmp_buf.h
@@ -19,6 +19,13 @@ typedef struct {
   __UINT64_TYPE__ r15;
   __UINTPTR_TYPE__ rsp;
   __UINTPTR_TYPE__ rip;
+#elif defined(__i386__)
+  long ebx;
+  long esi;
+  long edi;
+  long ebp;
+  long esp;
+  long eip;
 #elif defined(__riscv)
   /* Program counter.  */
   long int __pc;

diff  --git a/libc/src/setjmp/x86_64/longjmp.cpp b/libc/src/setjmp/x86_64/longjmp.cpp
index c293c55a6f9fb2..143c9deb11e9aa 100644
--- a/libc/src/setjmp/x86_64/longjmp.cpp
+++ b/libc/src/setjmp/x86_64/longjmp.cpp
@@ -11,12 +11,34 @@
 #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__
+[[gnu::naked]]
+LLVM_LIBC_FUNCTION(void, longjmp, (jmp_buf, int)) {
+  asm(R"(
+      mov 0x4(%%esp), %%ecx
+      mov 0x8(%%esp), %%eax
+      cmpl $0x1, %%eax
+      adcl $0x0, %%eax
+
+      mov %c[ebx](%%ecx), %%ebx
+      mov %c[esi](%%ecx), %%esi
+      mov %c[edi](%%ecx), %%edi
+      mov %c[ebp](%%ecx), %%ebp
+      mov %c[esp](%%ecx), %%esp
+
+      jmp *%c[eip](%%ecx)
+      )" ::[ebx] "i"(offsetof(__jmp_buf, ebx)),
+      [esi] "i"(offsetof(__jmp_buf, esi)), [edi] "i"(offsetof(__jmp_buf, edi)),
+      [ebp] "i"(offsetof(__jmp_buf, ebp)), [esp] "i"(offsetof(__jmp_buf, esp)),
+      [eip] "i"(offsetof(__jmp_buf, eip)));
+}
+#else
 [[gnu::naked]]
 LLVM_LIBC_FUNCTION(void, longjmp, (jmp_buf, int)) {
   asm(R"(
@@ -38,5 +60,6 @@ LLVM_LIBC_FUNCTION(void, longjmp, (jmp_buf, int)) {
       [r15] "i"(offsetof(__jmp_buf, r15)), [rsp] "i"(offsetof(__jmp_buf, rsp)),
       [rip] "i"(offsetof(__jmp_buf, rip)));
 }
+#endif
 
 } // namespace LIBC_NAMESPACE_DECL

diff  --git a/libc/src/setjmp/x86_64/setjmp.cpp b/libc/src/setjmp/x86_64/setjmp.cpp
index f6e82642edd7da..5ac10fa87b39a3 100644
--- a/libc/src/setjmp/x86_64/setjmp.cpp
+++ b/libc/src/setjmp/x86_64/setjmp.cpp
@@ -11,12 +11,37 @@
 #include "src/__support/macros/config.h"
 #include "src/setjmp/setjmp_impl.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__
+[[gnu::naked]]
+LLVM_LIBC_FUNCTION(int, setjmp, (jmp_buf buf)) {
+  asm(R"(
+      mov 4(%%esp), %%eax
+
+      mov %%ebx, %c[ebx](%%eax)
+      mov %%esi, %c[esi](%%eax)
+      mov %%edi, %c[edi](%%eax)
+      mov %%ebp, %c[ebp](%%eax)
+
+      lea 4(%%esp), %%ecx
+      mov %%ecx, %c[esp](%%eax)
+
+      mov (%%esp), %%ecx
+      mov %%ecx, %c[eip](%%eax)
+
+      xorl %%eax, %%eax
+      retl)" ::[ebx] "i"(offsetof(__jmp_buf, ebx)),
+      [esi] "i"(offsetof(__jmp_buf, esi)), [edi] "i"(offsetof(__jmp_buf, edi)),
+      [ebp] "i"(offsetof(__jmp_buf, ebp)), [esp] "i"(offsetof(__jmp_buf, esp)),
+      [eip] "i"(offsetof(__jmp_buf, eip))
+      : "eax", "ecx");
+}
+#else
 [[gnu::naked]]
 LLVM_LIBC_FUNCTION(int, setjmp, (jmp_buf buf)) {
   asm(R"(
@@ -41,5 +66,6 @@ LLVM_LIBC_FUNCTION(int, setjmp, (jmp_buf buf)) {
       [rip] "i"(offsetof(__jmp_buf, rip))
       : "rax");
 }
+#endif
 
 } // namespace LIBC_NAMESPACE_DECL