[MemProf] Add option to print function GUIDs during matching

For debugging, add -memprof-function-guids option that will cause
memprof matching to emit the computed function GUID for every function
definition in the module to stderr. This is helpful because the profile
only contains the function GUID and not the names.

Author: teresajohnson

llvm/lib/Transforms/Instrumentation/MemProfUse.cpp

@@ -62,6 +62,11 @@ static cl::opt<bool>
                                      "context in this module's profiles"),
                             cl::Hidden, cl::init(false));
 
+static cl::opt<bool>
+    PrintFunctionGuids("memprof-function-guids",
+                       cl::desc("Print function GUIDs computed for matching"),
+                       cl::Hidden, cl::init(false));
+
 static cl::opt<bool>
     SalvageStaleProfile("memprof-salvage-stale-profile",
                         cl::desc("Salvage stale MemProf profile"),
@@ -562,6 +567,9 @@ static void readMemprof(Module &M, Function &F,
   // linkage function.
   auto FuncName = F.getName();
   auto FuncGUID = Function::getGUIDAssumingExternalLinkage(FuncName);
+  if (PrintFunctionGuids)
+    errs() << "MemProf: Function GUID " << FuncGUID << " is " << FuncName
+           << "\n";
   std::optional<memprof::MemProfRecord> MemProfRec;
   auto Err = MemProfReader->getMemProfRecord(FuncGUID).moveInto(MemProfRec);
   if (Err) {

llvm/test/Transforms/PGOProfile/memprof-dump-matched-alloc-site.ll

@@ -26,7 +26,7 @@
 ; REQUIRES: x86_64-linux
 ; RUN: split-file %s %t
 ; RUN: llvm-profdata merge %t/memprof-dump-matched-alloc-site.yaml -o %t/memprof-dump-matched-alloc-site.memprofdata
-; RUN: opt < %t/memprof-dump-matched-alloc-site.ll -passes='memprof-use<profile-filename=%t/memprof-dump-matched-alloc-site.memprofdata>' -memprof-print-match-info -S 2>&1 | FileCheck %s
+; RUN: opt < %t/memprof-dump-matched-alloc-site.ll -passes='memprof-use<profile-filename=%t/memprof-dump-matched-alloc-site.memprofdata>' -memprof-print-match-info -memprof-function-guids -S 2>&1 | FileCheck %s
 
 ;--- memprof-dump-matched-alloc-site.yaml
 ---
@@ -77,6 +77,13 @@ HeapProfileRecords:
       # Kept empty here because this section is irrelevant for this test.
 ...
 ;--- memprof-dump-matched-alloc-site.ll
+
+;; From -memprof-function-guids
+; CHECK: MemProf: Function GUID 4708092051066754107 is _Z2f1v
+; CHECK: MemProf: Function GUID 14255129117669598641 is _Z2f2v
+; CHECK: MemProf: Function GUID 2771528421763978342 is _Z2f3v
+
+;; From -memprof-print-match-info
 ; CHECK: MemProf notcold context with id 5736731103568718490 has total profiled size 3 is matched with 1 frames
 ; CHECK: MemProf notcold context with id 5736731103568718490 has total profiled size 3 is matched with 2 frames
 ; CHECK: MemProf notcold context with id 5736731103568718490 has total profiled size 3 is matched with 3 frames