[llvm-profgen] Truncate the context with zero probe ID

Due to the debug info merging, there may have some contexts with zero probe id, we should truncate the context to avoid misleading pre-inliner.

Reviewed By: hoy, wenlei

Differential Revision: https://reviews.llvm.org/D114284

diff --git a/llvm/tools/llvm-profgen/ProfileGenerator.cpp b/llvm/tools/llvm-profgen/ProfileGenerator.cpp
index 7d28bda..0b90352 100644 (file)
--- a/llvm/tools/llvm-profgen/ProfileGenerator.cpp
+++ b/llvm/tools/llvm-profgen/ProfileGenerator.cpp
@@ -842,12 +842,12 @@ void CSProfileGenerator::populateBodySamplesWithProbes(
       FunctionProfile.addHeadSamples(Count);
       // Look up for the caller's function profile
       const auto *InlinerDesc = Binary->getInlinerDescForProbe(Probe);
-      if (InlinerDesc != nullptr) {
+      SampleContextFrames CalleeContextId =
+          FunctionProfile.getContext().getContextFrames();
+      if (InlinerDesc != nullptr && CalleeContextId.size() > 1) {
         // Since the context id will be compressed, we have to use callee's
         // context id to infer caller's context id to ensure they share the
         // same context prefix.
-        SampleContextFrames CalleeContextId =
-            FunctionProfile.getContext().getContextFrames();
         SampleContextFrameVector CallerContextId;
         SampleContextFrame &&CallerLeafFrameLoc =
             getCallerContext(CalleeContextId, CallerContextId);

diff --git a/llvm/tools/llvm-profgen/ProfiledBinary.h b/llvm/tools/llvm-profgen/ProfiledBinary.h
index a28ba82..3d32cba 100644 (file)
--- a/llvm/tools/llvm-profgen/ProfiledBinary.h
+++ b/llvm/tools/llvm-profgen/ProfiledBinary.h
@@ -476,7 +476,13 @@ public:
     SmallVector<MCPseduoProbeFrameLocation, 16> ProbeInlineContext;
     ProbeDecoder.getInlineContextForProbe(Probe, ProbeInlineContext,
                                           IncludeLeaf);
-    for (auto &Callsite : ProbeInlineContext) {
+    for (uint32_t I = 0; I < ProbeInlineContext.size(); I++) {
+      auto &Callsite = ProbeInlineContext[I];
+      // Clear the current context for an unknown probe.
+      if (Callsite.second == 0 && I != ProbeInlineContext.size() - 1) {
+        InlineContextStack.clear();
+        continue;
+      }
       InlineContextStack.emplace_back(Callsite.first,
                                       LineLocation(Callsite.second, 0));
     }