release/19.x: [LoongArch][sanitizer] Fix SC_ADDRERR_{RD,WR} missing in the musl environment (#108557)

[llvmbot]

Backport 1825cf2

Requested by: @heiher

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: None (llvmbot)

Changes

Backport 1825cf2

Requested by: @heiher

---

Full diff: https://github.com/llvm/llvm-project/pull/109110.diff

1 Files Affected:

• (modified) compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp (+12)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
index 648df0c4e5a760..b9b1f496df7c98 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -2014,6 +2014,18 @@ SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
     return Unknown;
   return esr & ESR_ELx_WNR ? Write : Read;
 #  elif defined(__loongarch__)
+  // In the musl environment, the Linux kernel uapi sigcontext.h is not
+  // included in signal.h. To avoid missing the SC_ADDRERR_{RD,WR} macros,
+  // copy them here. The LoongArch Linux kernel uapi is already stable,
+  // so there's no need to worry about the value changing.
+#    ifndef SC_ADDRERR_RD
+  // Address error was due to memory load
+#      define SC_ADDRERR_RD (1 << 30)
+#    endif
+#    ifndef SC_ADDRERR_WR
+  // Address error was due to memory store
+#      define SC_ADDRERR_WR (1 << 31)
+#    endif
   u32 flags = ucontext->uc_mcontext.__flags;
   if (flags & SC_ADDRERR_RD)
     return SignalContext::Read;

[heiher]

The purpose of cherry-picking this patch into the 19.x release branch is to resolve a build failure. This enables Rust loongarch64-unknown-linux-musl target to support sanitizers starting from LLVM 19.x. This patch is a straightforward fix for a build issue and does not introduce any functional changes, so there is no apparent risk involved.

[tru]

Looks safe enough.

[github-actions]

@heiher (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.