[PATCH] D95480: [NFC] Fix bug with parsing trace line

[Lei Wang via Phabricator via llvm-commits]

wlei created this revision.
Herald added subscribers: hoy, wenlei, lxfind.
wlei requested review of this revision.
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Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D95480

Files:
  llvm/tools/llvm-profgen/PerfReader.cpp


Index: llvm/tools/llvm-profgen/PerfReader.cpp
===================================================================
--- llvm/tools/llvm-profgen/PerfReader.cpp
+++ llvm/tools/llvm-profgen/PerfReader.cpp
@@ -406,11 +406,12 @@
   ProfiledBinary *Binary = nullptr;
   while (!TraceIt.isAtEoF() && !TraceIt.getCurrentLine().startswith(" 0x")) {
     StringRef FrameStr = TraceIt.getCurrentLine().ltrim();
-    // We might get an empty line at the beginning or comments, skip it
     uint64_t FrameAddr = 0;
     if (FrameStr.getAsInteger(16, FrameAddr)) {
+      // We might parse a non-perf sample line like empty line and comments,
+      // skip it
       TraceIt.advance();
-      break;
+      return false;
     }
     TraceIt.advance();
     if (!Binary) {
@@ -437,8 +438,6 @@
     CallStack.emplace_back(FrameAddr);
   }
 
-  if (CallStack.empty())
-    return false;
   // Skip other unrelated line, find the next valid LBR line
   while (!TraceIt.isAtEoF() && !TraceIt.getCurrentLine().startswith(" 0x")) {
     TraceIt.advance();
@@ -451,7 +450,8 @@
   // of such case - when sample landed in prolog/epilog, somehow stack
   // walking will be broken in an unexpected way that higher frames will be
   // missing.
-  return !Binary->addressInPrologEpilog(CallStack.front());
+  return !CallStack.empty() &&
+         !Binary->addressInPrologEpilog(CallStack.front());
 }
 
 void PerfReader::parseHybridSample(TraceStream &TraceIt) {


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