[llvm-branch-commits] [compiler-rt] release/19.x: [sanitizer_common] Fix UnwindFast on SPARC (#101634) (PR #101848)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

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

Author: None (llvmbot)

<details>
<summary>Changes</summary>

Backport 3368a3245ce5049b090d7c1081c2d52a6b6fda68

Requested by: @<!-- -->rorth

---
Full diff: https://github.com/llvm/llvm-project/pull/101848.diff


1 Files Affected:

- (modified) compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp (+5-6) 


``````````diff
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp
index a2000798a3907..74f435287af3c 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp
@@ -58,17 +58,16 @@ void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top,
   // Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
   while (IsValidFrame(bp, stack_top, bottom) && IsAligned(bp, sizeof(uhwptr)) &&
          size < max_depth) {
-    uhwptr pc1 = ((uhwptr *)bp)[15];
+    // %o7 contains the address of the call instruction and not the
+    // return address, so we need to compensate.
+    uhwptr pc1 = GetNextInstructionPc(((uhwptr *)bp)[15]);
     // Let's assume that any pointer in the 0th page is invalid and
     // stop unwinding here.  If we're adding support for a platform
     // where this isn't true, we need to reconsider this check.
     if (pc1 < kPageSize)
       break;
-    if (pc1 != pc) {
-      // %o7 contains the address of the call instruction and not the
-      // return address, so we need to compensate.
-      trace_buffer[size++] = GetNextInstructionPc((uptr)pc1);
-    }
+    if (pc1 != pc)
+      trace_buffer[size++] = pc1;
     bottom = bp;
     bp = (uptr)((uhwptr *)bp)[14] + STACK_BIAS;
   }

``````````

</details>


https://github.com/llvm/llvm-project/pull/101848