[libc-commits] [libc] [libc] implement sigsetjmp/siglongjmp for riscv (PR #137992)

[via libc-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Schrodinger ZHU Yifan (SchrodingerZhu)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/137992.diff


4 Files Affected:

- (modified) libc/config/linux/riscv/entrypoints.txt (+2) 
- (modified) libc/include/llvm-libc-types/jmp_buf.h (+2-1) 
- (modified) libc/src/setjmp/riscv/CMakeLists.txt (+16) 
- (added) libc/src/setjmp/riscv/sigsetjmp.cpp (+49) 


``````````diff
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index f2f895117e35a..e0b20e4ff24b5 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -877,6 +877,8 @@ 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 7e7d2da8a932a..2fec35dbc9163 100644
--- a/libc/include/llvm-libc-types/jmp_buf.h
+++ b/libc/include/llvm-libc-types/jmp_buf.h
@@ -12,7 +12,8 @@
 // TODO: implement sigjmp_buf related functions for other architectures
 // Issue: https://github.com/llvm/llvm-project/issues/136358
 #if defined(__linux__)
-#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) ||        \
+    defined(__riscv)
 #define __LIBC_HAS_SIGJMP_BUF
 #endif
 #endif
diff --git a/libc/src/setjmp/riscv/CMakeLists.txt b/libc/src/setjmp/riscv/CMakeLists.txt
index c68e318a0f08b..1959e9c905e23 100644
--- a/libc/src/setjmp/riscv/CMakeLists.txt
+++ b/libc/src/setjmp/riscv/CMakeLists.txt
@@ -11,6 +11,22 @@ add_entrypoint_object(
     -fomit-frame-pointer
 )
 
+if (TARGET libc.src.setjmp.sigsetjmp_epilogue)
+  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
+  )
+endif()
+
 add_entrypoint_object(
   longjmp
   SRCS
diff --git a/libc/src/setjmp/riscv/sigsetjmp.cpp b/libc/src/setjmp/riscv/sigsetjmp.cpp
new file mode 100644
index 0000000000000..2c6d44203e150
--- /dev/null
+++ b/libc/src/setjmp/riscv/sigsetjmp.cpp
@@ -0,0 +1,49 @@
+//===-- 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"
+
+#if __riscv_xlen == 64
+#define STORE(A, B, C) "sd " #A ", %c[" #B "](" #C ")\n\t"
+#define LOAD(A, B, C) "ld " #A ", %c[" #B "](" #C ")\n\t"
+#elif __riscv_xlen == 32
+#define STORE(A, B, C) "sw " #A ", %c[" #B "](" #C ")\n\t"
+#define LOAD(A, B, C) "lw " #A ", %c[" #B "](" #C ")\n\t"
+#else
+#error "Unsupported RISC-V architecture"
+#endif
+
+namespace LIBC_NAMESPACE_DECL {
+[[gnu::naked]]
+LLVM_LIBC_FUNCTION(int, sigsetjmp, (sigjmp_buf, int)) {
+  // clang-format off
+  asm("beqz a1, .Lnosave\n\t"
+      STORE(ra, retaddr, a0)
+      STORE(s0, extra, a0)
+      "mv s0, a0\n\t"
+      "call %c[setjmp]\n\t"
+      "mv a1, a0\n\t"
+      "mv a0, s0\n\t"
+      LOAD(s0, extra, a0)
+      LOAD(ra, retaddr, a0)
+      "tail %c[epilogue]\n"
+".Lnosave:\n\t"
+      "tail %c[setjmp]"
+      // clang-format on
+      ::[retaddr] "i"(offsetof(__jmp_buf, sig_retaddr)),
+      [extra] "i"(offsetof(__jmp_buf, sig_extra)), [setjmp] "i"(setjmp),
+      [epilogue] "i"(sigsetjmp_epilogue)
+      : "a0", "a1", "s0");
+}
+
+} // namespace LIBC_NAMESPACE_DECL

``````````

</details>


https://github.com/llvm/llvm-project/pull/137992