[llvm] [SampleProfile] Fix bug where intentionally constructed function with empty name asserts. (PR #71479)

[William Junda Huang via llvm-commits]

https://github.com/huangjd created https://github.com/llvm/llvm-project/pull/71479

Normally SampleContext does not allow using an empty StirngRef to construct an object, this is to prevent bugs reading the profile. However empty names may be emitted by a function which its name is intentionally set to empty, or a bug in the remapper (which should be investigated separately) that remaps a non-empty name to an empty string. Regardless, converting it to FunctionId first will prevent the assert, and that assert check is unnecessary, which will be addressed in another patch

>From 453e690bfedc454fcd040c5d851f45cd25f882e8 Mon Sep 17 00:00:00 2001
From: William Huang <williamjhuang at google.com>
Date: Tue, 7 Nov 2023 02:33:46 +0000
Subject: [PATCH] [SampleProfile] Fix bug where intentionally constructed
 function with empty name asserts.

Normally SampleContext does not allow using an empty StirngRef to
construct an object, this is to prevent bugs reading the profile.
However empty names may be emitted by a function which its name is
intentionally set to empty, or a bug in the remapper (which should be
investigated separately) that remaps a non-empty name to an empty
string. Regardless, converting it to FunctionId first will prevent the
assert, and that assert check is unnecessary, which will be addressed in
another patch
---
 llvm/lib/Transforms/IPO/SampleProfile.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index a7773737ef16bd3..063f7b42022ff83 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -1630,7 +1630,7 @@ void SampleProfileLoader::promoteMergeNotInlinedContextSamples(
         // separate map so that it does not rehash the original profile.
         if (!OutlineFS)
           OutlineFS = &OutlineFunctionSamples[
-              FunctionSamples::getCanonicalFnName(Callee->getName())];
+              FunctionId(FunctionSamples::getCanonicalFnName(Callee->getName()))];
         OutlineFS->merge(*FS, 1);
         // Set outlined profile to be synthetic to not bias the inliner.
         OutlineFS->SetContextSynthetic();
@@ -2675,12 +2675,12 @@ bool SampleProfileLoader::runOnFunction(Function &F, ModuleAnalysisManager *AM)
     // into base.
     if (!Samples) {
       StringRef CanonName = FunctionSamples::getCanonicalFnName(F);
-      auto It = OutlineFunctionSamples.find(CanonName);
+      auto It = OutlineFunctionSamples.find(FunctionId(CanonName));
       if (It != OutlineFunctionSamples.end()) {
         Samples = &It->second;
       } else if (auto Remapper = Reader->getRemapper()) {
         if (auto RemppedName = Remapper->lookUpNameInProfile(CanonName)) {
-          It = OutlineFunctionSamples.find(*RemppedName);
+          It = OutlineFunctionSamples.find(FunctionId(*RemppedName));
           if (It != OutlineFunctionSamples.end())
             Samples = &It->second;
         }