[PATCH] D109638: [CSSPGO] Truncate stack samples with invalid return address.

[Hongtao Yu via Phabricator via llvm-commits]

hoy updated this revision to Diff 372042.
hoy edited the summary of this revision.
hoy added a comment.

Updating D109638 <https://reviews.llvm.org/D109638>: [CSSPGO] Truncate stack samples with invalid return address.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109638/new/

https://reviews.llvm.org/D109638

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
@@ -7,15 +7,23 @@
 //===----------------------------------------------------------------------===//
 #include "PerfReader.h"
 #include "ProfileGenerator.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/Support/FileSystem.h"
 
+#define DEBUG_TYPE "perf-reader"
+
+STATISTIC(NumStackSamplesWithInvalidReturnAddress,
+          "Number of stack samples with an invalid return address");
+
+STATISTIC(NumStackSamples, "Number of stack samples");
+
 static cl::opt<bool> ShowMmapEvents("show-mmap-events", cl::ReallyHidden,
                                     cl::init(false), cl::ZeroOrMore,
                                     cl::desc("Print binary load events."));
 
 cl::opt<bool> SkipSymbolization("skip-symbolization", cl::ReallyHidden,
                                 cl::init(false), cl::ZeroOrMore,
-                                cl::desc("Dump the unsumbolized profile to the "
+                                cl::desc("Dump the unsymbolized profile to the "
                                          "output file. It will show unwinder "
                                          "output for CS profile generation."));
 
@@ -510,15 +518,24 @@
     if (!Binary->addressIsCode(FrameAddr))
       break;
 
-    // We need to translate return address to call address
-    // for non-leaf frames
+    // We need to translate return address to call address for non-leaf frames.
     if (!CallStack.empty()) {
-      FrameAddr = Binary->getCallAddrFromFrameAddr(FrameAddr);
+      auto I = Binary->getIndexForAddr(FrameAddr);
+      FrameAddr = I ? Binary->getAddressforIndex(I - 1) : 0;
+      // Stop at an invalid return address caused by bad unwinding. This could
+      // happen to frame-pointer-based unwinding and the callee functions that
+      // do not have the frame pointer chain set up.
+      if (!FrameAddr || !Binary->addressIsCall(FrameAddr)) {
+        NumStackSamplesWithInvalidReturnAddress++;
+        break;
+      }
     }
 
     CallStack.emplace_back(FrameAddr);
   }
 
+  NumStackSamples++;
+
   // Skip other unrelated line, find the next valid LBR line
   // Note that even for empty call stack, we should skip the address at the
   // bottom, otherwise the following pass may generate a truncated callstack


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