[PATCH] D144174: [Support][RISCV] Disable use of backtrace() for RISC-V backtraces

[Luís Marques via Phabricator via llvm-commits]

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AFAIK `backtrace` is fundamentally broken for RISC-V, even if you compile everything with frame pointers. Even if it could be fixed, right now it's broken in ~all systems so I think it's best to disable it for RISC-V.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D144174

Files:
  llvm/lib/Support/Unix/Signals.inc


Index: llvm/lib/Support/Unix/Signals.inc
===================================================================
--- llvm/lib/Support/Unix/Signals.inc
+++ llvm/lib/Support/Unix/Signals.inc
@@ -561,8 +561,11 @@
 #if ENABLE_BACKTRACES
   static void *StackTrace[256];
   int depth = 0;
-#if defined(HAVE_BACKTRACE)
+#if defined(HAVE_BACKTRACE) && !defined(__riscv)
   // Use backtrace() to output a backtrace on Linux systems with glibc.
+  // Don't use it on RISC-V Linux because it's highly unlikely to work but it
+  // may return 1 or 2 entries, preventing the retry with _Unwind_Backtrace
+  // below.
   if (!depth)
     depth = backtrace(StackTrace, static_cast<int>(std::size(StackTrace)));
 #endif


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