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[libc][i386] setjmp/longjmp #112437
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[libc][i386] setjmp/longjmp #112437
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@llvm/pr-subscribers-libc Author: Nick Desaulniers (nickdesaulniers) ChangesLink: #93709 Full diff: https://github.com/llvm/llvm-project/pull/112437.diff 4 Files Affected:
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/longjmp.h b/libc/src/setjmp/longjmp.h
index 7cb12b3392ae16..e8d6985f44ee4d 100644
--- a/libc/src/setjmp/longjmp.h
+++ b/libc/src/setjmp/longjmp.h
@@ -14,6 +14,7 @@
namespace LIBC_NAMESPACE_DECL {
+[[noreturn]]
void longjmp(jmp_buf buf, int val);
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/setjmp/x86_64/longjmp.cpp b/libc/src/setjmp/x86_64/longjmp.cpp
index d4b55565cb2187..f27e5f055d6f99 100644
--- a/libc/src/setjmp/x86_64/longjmp.cpp
+++ b/libc/src/setjmp/x86_64/longjmp.cpp
@@ -6,16 +6,44 @@
//
//===----------------------------------------------------------------------===//
-#include "src/setjmp/longjmp.h"
+#include "include/llvm-libc-macros/offsetof-macro.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
+#include "src/setjmp/longjmp.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, int val)) {
+ asm(R"(
+ mov 4(%%esp), %%edx
+
+ mov %c[ebx](%%edx), %%ebx
+ mov %c[esi](%%edx), %%esi
+ mov %c[edi](%%edx), %%edi
+ mov %c[ebp](%%edx), %%ebp
+ mov %c[esp](%%edx), %%esp
+
+ jmp *%c[eip](%%edx)
+ )"
+ ::
+ [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)),
+ [val] "a"(val == 0 ? 1 : val) :
+ "edx");
+ __builtin_unreachable();
+}
+#else
+[[noreturn]]
LLVM_LIBC_FUNCTION(void, longjmp, (jmp_buf buf, int val)) {
register __UINT64_TYPE__ rbx __asm__("rbx");
register __UINT64_TYPE__ rbp __asm__("rbp");
@@ -41,5 +69,6 @@ LLVM_LIBC_FUNCTION(void, longjmp, (jmp_buf buf, int val)) {
LIBC_INLINE_ASM("mov %1, %0\n\t" : "=r"(rsp) : "m"(buf->rsp) :);
LIBC_INLINE_ASM("jmp *%0\n\t" : : "m"(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..90532c5654b33b 100644
--- a/libc/src/setjmp/x86_64/setjmp.cpp
+++ b/libc/src/setjmp/x86_64/setjmp.cpp
@@ -11,12 +11,40 @@
#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 +69,6 @@ LLVM_LIBC_FUNCTION(int, setjmp, (jmp_buf buf)) {
[rip] "i"(offsetof(__jmp_buf, rip))
: "rax");
}
+#endif
} // namespace LIBC_NAMESPACE_DECL
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
I'll land #112443 first, then revisit this in that style. |
ok, I've converted longjmp to be a naked fn using offsetof. I'll send a patch to fix up x86_64 in a distinct PR. Ready for rereview. |
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Link: #93709