From d97865e530df4ad2ed9c2a999edf0a19ee567e79 Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Wed, 18 Sep 2019 09:18:04 +0000
Subject: [PATCH] tsan: allow the Go runtime to return multiple stack frames
 for a single PC

This fix allows tsan to report stack traces correctly even in the
presence of mid-stack inlining by the Go compiler.

See https://go-review.googlesource.com/c/go/+/195781 for the Go runtime side of this change.

Author: randall77 (Keith Randall)
Reviewed: https://reviews.llvm.org/D67671
llvm-svn: 372205
---
 compiler-rt/lib/tsan/go/tsan_go.cpp | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/compiler-rt/lib/tsan/go/tsan_go.cpp b/compiler-rt/lib/tsan/go/tsan_go.cpp
index 271f6bc00cd0..f5998c0c7816 100644
--- a/compiler-rt/lib/tsan/go/tsan_go.cpp
+++ b/compiler-rt/lib/tsan/go/tsan_go.cpp
@@ -54,20 +54,31 @@ struct SymbolizeCodeContext {
 };
 
 SymbolizedStack *SymbolizeCode(uptr addr) {
-  SymbolizedStack *s = SymbolizedStack::New(addr);
-  SymbolizeCodeContext cbctx;
-  internal_memset(&cbctx, 0, sizeof(cbctx));
-  cbctx.pc = addr;
-  go_runtime_cb(CallbackSymbolizeCode, &cbctx);
-  if (cbctx.res) {
+  SymbolizedStack *first = SymbolizedStack::New(addr);
+  SymbolizedStack *s = first;
+  for (;;) {
+    SymbolizeCodeContext cbctx;
+    internal_memset(&cbctx, 0, sizeof(cbctx));
+    cbctx.pc = addr;
+    go_runtime_cb(CallbackSymbolizeCode, &cbctx);
+    if (cbctx.res == 0)
+      break;
     AddressInfo &info = s->info;
     info.module_offset = cbctx.off;
     info.function = internal_strdup(cbctx.func ? cbctx.func : "??");
     info.file = internal_strdup(cbctx.file ? cbctx.file : "-");
     info.line = cbctx.line;
     info.column = 0;
+
+    if (cbctx.pc == addr) // outermost (non-inlined) function
+      break;
+    addr = cbctx.pc;
+    // Allocate a stack entry for the parent of the inlined function.
+    SymbolizedStack *s2 = SymbolizedStack::New(addr);
+    s->next = s2;
+    s = s2;
   }
-  return s;
+  return first;
 }
 
 struct SymbolizeDataContext {
-- 
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