[InstrProf] No linkage prefixes in IRPGO names (#76994)

Change the format of IRPGO counter names to
`[<filepath>;]<mangled-name>` which is computed by
`GlobalValue::getGlobalIdentifier()` to fix #74565.

In fe051934cbb0aaf25d960d7d45305135635d650b
(https://reviews.llvm.org/D156569) the format of IRPGO counter names was
changed to be `[<filepath>;]<linkage-name>` where `<linkage-name>` is
basically `F.getName()` with some prefix, e.g., `_` or `l_` on Mach-O
(yes, it is confusing that `<linkage-name>` is computed with
`Mangler().getNameWithPrefix()` while `<mangled-name>` is just
`F.getName()`). We discovered in #74565 that this causes some missed
import issues on some targets and #74008 is a partial fix.

Since `<mangled-name>` may not match the `<linkage-name>` on some
targets like Mach-O, we will need to post-process the output of
`llvm-profdata order` before passing to the linker via `-order_file`.

Profiles generated after fe051934cbb0aaf25d960d7d45305135635d650b will
become stale after this diff, but I think this is acceptable since that
patch landed after the LLVM 18 cut which hasn't been released yet.

1 files changed, 2 insertions, 16 deletions

diff --git a/llvm/unittests/ProfileData/InstrProfTest.cpp b/llvm/unittests/ProfileData/InstrProfTest.cpp
index 6a71a97..8ffb68d 100644
--- a/llvm/unittests/ProfileData/InstrProfTest.cpp
+++ b/llvm/unittests/ProfileData/InstrProfTest.cpp
@@ -542,22 +542,14 @@ TEST_F(InstrProfTest, test_memprof_merge) {
 TEST_F(InstrProfTest, test_irpgo_function_name) {
   LLVMContext Ctx;
   auto M = std::make_unique<Module>("MyModule.cpp", Ctx);
-  // Use Mach-O mangling so that non-private symbols get a `_` prefix.
-  M->setDataLayout(DataLayout("m:o"));
   auto *FTy = FunctionType::get(Type::getVoidTy(Ctx), /*isVarArg=*/false);
 
   std::vector<std::tuple<StringRef, Function::LinkageTypes, StringRef>> Data;
-  Data.emplace_back("ExternalFoo", Function::ExternalLinkage, "_ExternalFoo");
+  Data.emplace_back("ExternalFoo", Function::ExternalLinkage, "ExternalFoo");
   Data.emplace_back("InternalFoo", Function::InternalLinkage,
-                    "MyModule.cpp;_InternalFoo");
-  Data.emplace_back("PrivateFoo", Function::PrivateLinkage,
-                    "MyModule.cpp;l_PrivateFoo");
-  Data.emplace_back("WeakODRFoo", Function::WeakODRLinkage, "_WeakODRFoo");
-  // Test Objective-C symbols
+                    "MyModule.cpp;InternalFoo");
   Data.emplace_back("\01-[C dynamicFoo:]", Function::ExternalLinkage,
                     "-[C dynamicFoo:]");
-  Data.emplace_back("-<C directFoo:>", Function::ExternalLinkage,
-                    "_-<C directFoo:>");
   Data.emplace_back("\01-[C internalFoo:]", Function::InternalLinkage,
                     "MyModule.cpp;-[C internalFoo:]");
 
@@ -590,10 +582,6 @@ TEST_F(InstrProfTest, test_pgo_function_name) {
   Data.emplace_back("ExternalFoo", Function::ExternalLinkage, "ExternalFoo");
   Data.emplace_back("InternalFoo", Function::InternalLinkage,
                     "MyModule.cpp:InternalFoo");
-  Data.emplace_back("PrivateFoo", Function::PrivateLinkage,
-                    "MyModule.cpp:PrivateFoo");
-  Data.emplace_back("WeakODRFoo", Function::WeakODRLinkage, "WeakODRFoo");
-  // Test Objective-C symbols
   Data.emplace_back("\01-[C externalFoo:]", Function::ExternalLinkage,
                     "-[C externalFoo:]");
   Data.emplace_back("\01-[C internalFoo:]", Function::InternalLinkage,
@@ -611,8 +599,6 @@ TEST_F(InstrProfTest, test_pgo_function_name) {
 TEST_F(InstrProfTest, test_irpgo_read_deprecated_names) {
   LLVMContext Ctx;
   auto M = std::make_unique<Module>("MyModule.cpp", Ctx);
-  // Use Mach-O mangling so that non-private symbols get a `_` prefix.
-  M->setDataLayout(DataLayout("m:o"));
   auto *FTy = FunctionType::get(Type::getVoidTy(Ctx), /*isVarArg=*/false);
   auto *InternalFooF =
       Function::Create(FTy, Function::InternalLinkage, "InternalFoo", M.get());