[libc] implement aarch64 sigsetjmp #136706

SchrodingerZhu · 2025-04-22T14:47:59Z

[libc][aarch64] implement sigsetjmp

On top of #136072
See also #137055 for remarks on naked attributes.

//===-- Implementation of setjmp ------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "src/setjmp/sigsetjmp.h"
#include "hdr/offsetof_macros.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
#include "src/setjmp/setjmp_impl.h"
#include "src/setjmp/sigsetjmp_epilogue.h"

namespace LIBC_NAMESPACE_DECL {
[[gnu::naked]]
LLVM_LIBC_FUNCTION(int, sigsetjmp, (sigjmp_buf, int)) {
  asm(R"(
      cbz w1, %c[setjmp]
      str x30, [x0, %c[retaddr]]
      str x19, [x0, %c[extra]]
      mov x19, x0
      bl %c[setjmp]
      mov w1, w0
      mov x0, x19
      ldr x30, [x0, %c[retaddr]]
      ldr x19, [x0, %c[extra]]
      b %c[epilogue])" ::[retaddr] "i"(offsetof(__jmp_buf, sig_retaddr)),
      [extra] "i"(offsetof(__jmp_buf, sig_extra)), [setjmp] "i"(setjmp),
      [epilogue] "i"(sigsetjmp_epilogue)
      : "x0", "x1", "x19", "x30");
}
} // namespace LIBC_NAMESPACE_DECL

llvmbot · 2025-04-23T20:03:05Z

@llvm/pr-subscribers-libc

Author: Schrodinger ZHU Yifan (SchrodingerZhu)

Changes

[libc][aarch64] implement sigsetjmp

On top of #136072

//===-- Implementation of setjmp ------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "src/setjmp/sigsetjmp.h"
#include "hdr/offsetof_macros.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
#include "src/setjmp/setjmp_impl.h"
#include "src/setjmp/sigsetjmp_epilogue.h"

namespace LIBC_NAMESPACE_DECL {
[[gnu::naked]]
LLVM_LIBC_FUNCTION(int, sigsetjmp, (sigjmp_buf, int)) {
  asm(R"(
      cbz w1, %c[setjmp]
      str x30, [x0, %c[retaddr]]
      str x19, [x0, %c[extra]]
      mov x19, x0
      bl %c[setjmp]
      mov w1, w0
      mov x0, x19
      ldr x30, [x0, %c[retaddr]]
      ldr x19, [x0, %c[extra]]
      b %c[epilogue])" ::[retaddr] "i"(offsetof(__jmp_buf, sig_retaddr)),
      [extra] "i"(offsetof(__jmp_buf, sig_extra)), [setjmp] "i"(setjmp),
      [epilogue] "i"(sigsetjmp_epilogue)
      : "x0", "x1", "x19", "x30");
}
} // namespace LIBC_NAMESPACE_DECL

Full diff: https://github.com/llvm/llvm-project/pull/136706.diff

4 Files Affected:

(modified) libc/config/linux/aarch64/entrypoints.txt (+2)
(modified) libc/include/llvm-libc-types/jmp_buf.h (+2-2)
(modified) libc/src/setjmp/aarch64/CMakeLists.txt (+14)
(added) libc/src/setjmp/aarch64/sigsetjmp.cpp (+36)

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index be5f5a66016b5..57058633ae50a 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -932,6 +932,8 @@ if(LLVM_LIBC_FULL_BUILD)
     # setjmp.h entrypoints
     libc.src.setjmp.longjmp
     libc.src.setjmp.setjmp
+    libc.src.setjmp.siglongjmp
+    libc.src.setjmp.sigsetjmp
 
     # stdio.h entrypoints
     libc.src.stdio.clearerr
diff --git a/libc/include/llvm-libc-types/jmp_buf.h b/libc/include/llvm-libc-types/jmp_buf.h
index 1e7791610857d..0376332f2a0dc 100644
--- a/libc/include/llvm-libc-types/jmp_buf.h
+++ b/libc/include/llvm-libc-types/jmp_buf.h
@@ -54,7 +54,7 @@ typedef struct {
 #endif
   // TODO: implement sigjmp_buf related functions for other architectures
   // Issue: https://github.com/llvm/llvm-project/issues/136358
-#if defined(__i386__) || defined(__x86_64__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
   // return address
   void *sig_retaddr;
   // extra register buffer to avoid indefinite stack growth in sigsetjmp
@@ -66,7 +66,7 @@ typedef struct {
 
 typedef __jmp_buf jmp_buf[1];
 
-#if defined(__i386__) || defined(__x86_64__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
 typedef __jmp_buf sigjmp_buf[1];
 #endif
 #endif // LLVM_LIBC_TYPES_JMP_BUF_H
diff --git a/libc/src/setjmp/aarch64/CMakeLists.txt b/libc/src/setjmp/aarch64/CMakeLists.txt
index e0e7702c7c4b6..1078af8ce04f3 100644
--- a/libc/src/setjmp/aarch64/CMakeLists.txt
+++ b/libc/src/setjmp/aarch64/CMakeLists.txt
@@ -26,3 +26,17 @@ add_entrypoint_object(
     libc.hdr.types.jmp_buf
   ${setjmp_config_options}
 )
+
+add_entrypoint_object(
+  sigsetjmp
+  SRCS
+    sigsetjmp.cpp
+  HDRS
+    ../sigsetjmp.h
+  DEPENDS
+    libc.hdr.types.jmp_buf
+    libc.hdr.types.sigset_t
+    libc.hdr.offsetof_macros
+    libc.src.setjmp.sigsetjmp_epilogue
+    libc.src.setjmp.setjmp
+)
diff --git a/libc/src/setjmp/aarch64/sigsetjmp.cpp b/libc/src/setjmp/aarch64/sigsetjmp.cpp
new file mode 100644
index 0000000000000..734591b2aca4c
--- /dev/null
+++ b/libc/src/setjmp/aarch64/sigsetjmp.cpp
@@ -0,0 +1,36 @@
+//===-- Implementation of sigsetjmp ---------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/setjmp/sigsetjmp.h"
+#include "hdr/offsetof_macros.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/setjmp/setjmp_impl.h"
+#include "src/setjmp/sigsetjmp_epilogue.h"
+
+namespace LIBC_NAMESPACE_DECL {
+[[gnu::naked]]
+LLVM_LIBC_FUNCTION(int, sigsetjmp, (sigjmp_buf, int)) {
+  asm(R"(
+      cbz w1, %c[setjmp]
+
+      str x30, [x0, %c[retaddr]]
+      str x19, [x0, %c[extra]]
+      mov x19, x0
+      bl %c[setjmp]
+
+      mov w1, w0
+      mov x0, x19
+      ldr x30, [x0, %c[retaddr]]
+      ldr x19, [x0, %c[extra]]
+      b %c[epilogue])" ::[retaddr] "i"(offsetof(__jmp_buf, sig_retaddr)),
+      [extra] "i"(offsetof(__jmp_buf, sig_extra)), [setjmp] "i"(setjmp),
+      [epilogue] "i"(sigsetjmp_epilogue)
+      : "x0", "x1", "x19", "x30");
+}
+} // namespace LIBC_NAMESPACE_DECL

Copilot

Pull Request Overview

A concise implementation of the aarch64 sigsetjmp functionality for libc.

Introduces a new sigsetjmp implementation in assembly in libc/src/setjmp/aarch64/sigsetjmp.cpp.
Updates jmp_buf.h to include aarch64 in the sigjmp_buf macro condition.
Adds new entrypoints for sigsetjmp and siglongjmp in the Linux aarch64 configuration.

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

File	Description
libc/src/setjmp/aarch64/sigsetjmp.cpp	Adds a new aarch64 implementation for sigsetjmp.
libc/include/llvm-libc-types/jmp_buf.h	Includes aarch64 in the sigsetjmp_buf conditions.
libc/config/linux/aarch64/entrypoints.txt	Updates Linux entrypoints with sigsetjmp and siglongjmp.

Files not reviewed (1)

libc/src/setjmp/aarch64/CMakeLists.txt: Language not supported

- **[libc][aarch64] implement sigsetjmp** On top of llvm#136072 See also llvm#137055 for remarks on naked attributes. ```c++ //===-- Implementation of setjmp ------------------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #include "src/setjmp/sigsetjmp.h" #include "hdr/offsetof_macros.h" #include "src/__support/common.h" #include "src/__support/macros/config.h" #include "src/setjmp/setjmp_impl.h" #include "src/setjmp/sigsetjmp_epilogue.h" namespace LIBC_NAMESPACE_DECL { [[gnu::naked]] LLVM_LIBC_FUNCTION(int, sigsetjmp, (sigjmp_buf, int)) { asm(R"( cbz w1, %c[setjmp] str x30, [x0, %c[retaddr]] str x19, [x0, %c[extra]] mov x19, x0 bl %c[setjmp] mov w1, w0 mov x0, x19 ldr x30, [x0, %c[retaddr]] ldr x19, [x0, %c[extra]] b %c[epilogue])" ::[retaddr] "i"(offsetof(__jmp_buf, sig_retaddr)), [extra] "i"(offsetof(__jmp_buf, sig_extra)), [setjmp] "i"(setjmp), [epilogue] "i"(sigsetjmp_epilogue) : "x0", "x1", "x19", "x30"); } } // namespace LIBC_NAMESPACE_DECL ```

SchrodingerZhu force-pushed the libc/sigsetjmp-for-aarch64 branch 2 times, most recently from a10a91f to f713e96 Compare April 22, 2025 15:01

SchrodingerZhu marked this pull request as ready for review April 22, 2025 15:14

SchrodingerZhu requested review from lntue, michaelrj-google, statham-arm and Copilot April 22, 2025 15:15

This comment was marked as outdated.

Sign in to view

[libc][aarch64] implement sigsetjmp

a325f7f

SchrodingerZhu force-pushed the libc/sigsetjmp-for-aarch64 branch from f713e96 to a325f7f Compare April 23, 2025 20:02

llvmbot added the libc label Apr 23, 2025

Merge branch 'main' into libc/sigsetjmp-for-aarch64

5d2dcd0

SchrodingerZhu requested a review from Copilot April 29, 2025 14:31

Copilot AI reviewed Apr 29, 2025

View reviewed changes

lntue approved these changes Apr 29, 2025

View reviewed changes

SchrodingerZhu merged commit 9ebaa9d into llvm:main Apr 29, 2025
16 checks passed

SchrodingerZhu deleted the libc/sigsetjmp-for-aarch64 branch April 29, 2025 20:37

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[libc] implement aarch64 sigsetjmp #136706

[libc] implement aarch64 sigsetjmp #136706

Uh oh!

SchrodingerZhu commented Apr 22, 2025 •

edited

Loading

Uh oh!

This comment was marked as outdated.

Uh oh!

llvmbot commented Apr 23, 2025

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Uh oh!

[libc] implement aarch64 sigsetjmp #136706

[libc] implement aarch64 sigsetjmp #136706

Uh oh!

Conversation

SchrodingerZhu commented Apr 22, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

This comment was marked as outdated.

Uh oh!

llvmbot commented Apr 23, 2025

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull Request Overview

Reviewed Changes

Uh oh!

Uh oh!

Uh oh!

SchrodingerZhu commented Apr 22, 2025 •

edited

Loading