[PATCH] D48510: [SampleFDO] Add an option to turn on/off warning about samples unused

[Wei Mi via Phabricator via llvm-commits]

wmi created this revision.
wmi added reviewers: danielcdh, tejohnson.
Herald added subscribers: JDevlieghere, aprantl.

If a function has sample to use, but cannot use them because of no debug information, currently a warning will be issued to inform the missing opportunity.

This warning assumes the binary generating the profile and the binary using the profile are similar enough. In some cases even if it is not similar enough, we may still get some benefit by using sampleFDO. In those cases, we may not want to see a lot of such warnings pop up.

The patch adds an option for the warning.


Repository:
  rL LLVM

https://reviews.llvm.org/D48510

Files:
  lib/Transforms/IPO/SampleProfile.cpp


Index: lib/Transforms/IPO/SampleProfile.cpp
===================================================================
--- lib/Transforms/IPO/SampleProfile.cpp
+++ lib/Transforms/IPO/SampleProfile.cpp
@@ -111,6 +111,11 @@
     cl::desc("Emit a warning if less than N% of samples in the input profile "
              "are matched to the IR."));
 
+static cl::opt<bool> NoWarnSampleUnused(
+    "no-warn-sample-unused", cl::init(false), cl::Hidden,
+    cl::desc("Use this option to turn off/on warnings about function with "
+             "samples but without debug information to use those samples. "));
+
 namespace {
 
 using BlockWeightMap = DenseMap<const BasicBlock *, uint64_t>;
@@ -1360,6 +1365,9 @@
   if (DISubprogram *S = F.getSubprogram())
     return S->getLine();
 
+  if (NoWarnSampleUnused)
+    return 0;
+
   // If the start of \p F is missing, emit a diagnostic to inform the user
   // about the missed opportunity.
   F.getContext().diagnose(DiagnosticInfoSampleProfile(


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