[libunwind] [libunwind][Haiku] Fix signal frame unwinding (PR #135367)

[Trung Nguyen via cfe-commits]

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@@ -3032,6 +2980,93 @@ int UnwindCursor<A, R>::stepThroughSigReturn(Registers_s390x &) {
 #endif // defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) &&
        // defined(_LIBUNWIND_TARGET_S390X)
 
+#if defined(_LIBUNWIND_CHECK_HAIKU_SIGRETURN)
+static size_t signalHandlerSize = 0;
+
+template <typename A, typename R>
+bool UnwindCursor<A, R>::setInfoForSigReturn() {
+  Dl_info dlinfo;
+  auto isSignalHandler = [&](pint_t addr) {
+    if (!dladdr(reinterpret_cast<void *>(addr), &dlinfo))
+      return false;
+    if (strcmp(dlinfo.dli_fname, "commpage"))
+      return false;
+    if (dlinfo.dli_sname == NULL ||
+        strcmp(dlinfo.dli_sname, "commpage_signal_handler"))
+      return false;
+    return true;
+  };
+
+  pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
+  if (!isSignalHandler(pc))
+    return false;
+
+  pint_t start = reinterpret_cast<pint_t>(dlinfo.dli_saddr);
+
+  if (signalHandlerSize == 0) {
+    size_t boundLow = 0;
+    size_t boundHigh = static_cast<size_t>(-1);
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trungnt2910 wrote:

Done.

https://github.com/llvm/llvm-project/pull/135367