Revert "[PGO][AMDGPU] Add basic HIP offload PGO support (#177665)" (#201416)

This broke profiling builds on Windows by switching the profile library
to link against the dynamic CRT; see discussion on the PR.

There were already a number of issues reported and fixed after this PR.
Rather than piling on the fixes (and this one may need some work),
revert back to green for now to let the project recover.

This reverts commit 5db1364.

Additionally, this reverts the followup PRs in
635e120,
2766733,
4c33844, and
5eca8b6:

"[PGO][HIP] Stop pulling ROCm.o into every PGO host link (#200101)"
"[compiler-rt][profile] Add COMPILER_RT_BUILD_PROFILE_ROCM option
(#200127)"
"[PGO][HIP] Skip ROCm interceptor in profile-only compiler-rt builds
(#200111)"
"[PGO][HIP] Fix profile-only Windows link by gating ROCm interceptor
macro (#200859)"

Author: zmodem

clang/lib/CodeGen/CGCUDANV.cpp

@@ -28,7 +28,6 @@
 #include "llvm/IR/ReplaceConstant.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/VirtualFileSystem.h"
-#include "llvm/Transforms/Utils/ModuleUtils.h"
 
 using namespace clang;
 using namespace CodeGen;
@@ -73,11 +72,6 @@ class CGNVCUDARuntime : public CGCUDARuntime {
   /// ModuleCtorFunction() and used to create corresponding cleanup calls in
   /// ModuleDtorFunction()
   llvm::GlobalVariable *GpuBinaryHandle = nullptr;
-  /// Host-side shadow for the per-TU __llvm_profile_sections_<CUID> global,
-  /// emitted only for HIP host compiles when PGO is on. Registered via
-  /// __hipRegisterVar (non-RDC) or an offloading entry (RDC) so the runtime
-  /// can locate the device-side table by name.
-  llvm::GlobalVariable *OffloadProfShadow = nullptr;
   /// Whether we generate relocatable device code.
   bool RelocatableDeviceCode;
   /// Mangle context for device.
@@ -182,13 +176,6 @@ class CGNVCUDARuntime : public CGCUDARuntime {
   void transformManagedVars();
   /// Create offloading entries to register globals in RDC mode.
   void createOffloadingEntries();
-  /// For HIP+PGO, emit the per-TU __llvm_profile_sections_<CUID> global.
-  /// On the device side it is the populated 7-pointer section-bounds table.
-  /// On the host side it is a placeholder void* shadow stored in
-  /// OffloadProfShadow, registered later by makeRegisterGlobalsFn (non-RDC)
-  /// or createOffloadingEntries (RDC) so the runtime can locate the
-  /// device-side table by name.
-  void emitOffloadProfilingSections();
 
 public:
   CGNVCUDARuntime(CodeGenModule &CGM);
@@ -748,32 +735,6 @@ llvm::Function *CGNVCUDARuntime::makeRegisterGlobalsFn() {
     }
   }
 
-  // Register the per-TU offload-profiling shadow so the host runtime can
-  // locate the matching device-side __llvm_profile_sections_<CUID>. We
-  // emit both __hipRegisterVar (so the HIP runtime can map the host
-  // shadow to the device symbol) and
-  // __llvm_profile_offload_register_shadow_variable (so the profile
-  // runtime adds the shadow to its drain list).
-  if (OffloadProfShadow) {
-    llvm::Constant *Name =
-        makeConstantString(std::string(OffloadProfShadow->getName()));
-    llvm::Value *RegisterVarArgs[] = {
-        &GpuBinaryHandlePtr,
-        OffloadProfShadow,
-        Name,
-        Name,
-        llvm::ConstantInt::get(IntTy, /*Extern=*/0),
-        llvm::ConstantInt::get(VarSizeTy, CGM.getDataLayout().getPointerSize()),
-        llvm::ConstantInt::get(IntTy, /*Constant=*/0),
-        llvm::ConstantInt::get(IntTy, 0)};
-    Builder.CreateCall(RegisterVar, RegisterVarArgs);
-
-    llvm::FunctionCallee RegisterShadow = CGM.CreateRuntimeFunction(
-        llvm::FunctionType::get(VoidTy, {PtrTy}, false),
-        "__llvm_profile_offload_register_shadow_variable");
-    Builder.CreateCall(RegisterShadow, {OffloadProfShadow});
-  }
-
   Builder.CreateRetVoid();
   return RegisterKernelsFunc;
 }
@@ -1295,124 +1256,11 @@ void CGNVCUDARuntime::createOffloadingEntries() {
           I.Flags.getSurfTexType());
     }
   }
-
-  // Register the per-TU offload-profiling shadow. The offloading entry
-  // makes the linker-wrapper emit the host __hipRegisterVar call in the
-  // combined ctor. Separately emit a per-TU ctor that registers the
-  // shadow with the profile runtime's drain list.
-  if (OffloadProfShadow) {
-    llvm::offloading::emitOffloadingEntry(
-        M, Kind, OffloadProfShadow, OffloadProfShadow->getName(),
-        CGM.getDataLayout().getPointerSize(),
-        llvm::offloading::OffloadGlobalEntry, /*Data=*/0);
-
-    llvm::LLVMContext &Ctx = M.getContext();
-    auto *PtrTy = llvm::PointerType::getUnqual(Ctx);
-    llvm::FunctionCallee RegisterShadow = CGM.CreateRuntimeFunction(
-        llvm::FunctionType::get(VoidTy, {PtrTy}, false),
-        "__llvm_profile_offload_register_shadow_variable");
-    auto *CtorFn = llvm::Function::Create(
-        llvm::FunctionType::get(VoidTy, false),
-        llvm::GlobalValue::InternalLinkage,
-        "__llvm_profile_register_shadow." + CGM.getContext().getCUIDHash(), &M);
-    auto *Entry = llvm::BasicBlock::Create(Ctx, "entry", CtorFn);
-    llvm::IRBuilder<> B(Entry);
-    B.CreateCall(RegisterShadow, {OffloadProfShadow});
-    B.CreateRetVoid();
-    llvm::appendToGlobalCtors(M, CtorFn, /*Priority=*/65535);
-  }
-}
-
-// For HIP host+device compiles with PGO enabled, emit the per-TU global
-// __llvm_profile_sections_<CUID>. Device side: a 7-pointer struct holding
-// section start/stop bounds for the names/counters/data sections plus the
-// raw-version variable. Host side: an opaque void* shadow whose only
-// purpose is to give the host-runtime a registered symbol name to look up
-// via hipGetSymbolAddress; the actual device-side data lives in the
-// matching device-side global.
-void CGNVCUDARuntime::emitOffloadProfilingSections() {
-  if (!CGM.getLangOpts().HIP)
-    return;
-  if (!CGM.getCodeGenOpts().hasProfileInstr())
-    return;
-
-  StringRef CUIDHash = CGM.getContext().getCUIDHash();
-  if (CUIDHash.empty())
-    return;
-
-  llvm::Module &M = CGM.getModule();
-  llvm::LLVMContext &Ctx = M.getContext();
-  std::string Name = ("__llvm_profile_sections_" + CUIDHash).str();
-
-  // If the global already exists (e.g. another TU was merged in), don't
-  // duplicate it.
-  if (M.getNamedValue(Name))
-    return;
-
-  if (CGM.getLangOpts().CUDAIsDevice) {
-    // Device side: emit the populated struct. Section start/stop symbols
-    // are linker-defined (ELF auto-generates __start_/__stop_ for any
-    // section whose name is a valid C identifier; AMDGPU is ELF).
-    unsigned GlobalAS = M.getDataLayout().getDefaultGlobalsAddressSpace();
-    auto *PtrTy = llvm::PointerType::get(Ctx, GlobalAS);
-    auto getOrDeclare = [&](StringRef SymName) {
-      if (auto *GV = M.getNamedGlobal(SymName))
-        return GV;
-      auto *GV = new llvm::GlobalVariable(
-          M, llvm::Type::getInt8Ty(Ctx), /*isConstant=*/false,
-          llvm::GlobalValue::ExternalLinkage, /*Initializer=*/nullptr, SymName,
-          /*InsertBefore=*/nullptr, llvm::GlobalValue::NotThreadLocal,
-          GlobalAS);
-      GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
-      return GV;
-    };
-    auto *VersionGV = M.getNamedGlobal("__llvm_profile_raw_version");
-    if (!VersionGV) {
-      VersionGV = new llvm::GlobalVariable(
-          M, llvm::Type::getInt64Ty(Ctx), /*isConstant=*/true,
-          llvm::GlobalValue::ExternalLinkage, /*Initializer=*/nullptr,
-          "__llvm_profile_raw_version",
-          /*InsertBefore=*/nullptr, llvm::GlobalValue::NotThreadLocal,
-          GlobalAS);
-    }
-
-    auto *StructTy = llvm::StructType::get(
-        Ctx, {PtrTy, PtrTy, PtrTy, PtrTy, PtrTy, PtrTy, PtrTy});
-    llvm::Constant *Fields[] = {
-        getOrDeclare("__start___llvm_prf_names"),
-        getOrDeclare("__stop___llvm_prf_names"),
-        getOrDeclare("__start___llvm_prf_cnts"),
-        getOrDeclare("__stop___llvm_prf_cnts"),
-        getOrDeclare("__start___llvm_prf_data"),
-        getOrDeclare("__stop___llvm_prf_data"),
-        VersionGV,
-    };
-    auto *Init = llvm::ConstantStruct::get(StructTy, Fields);
-    auto *GV = new llvm::GlobalVariable(
-        M, StructTy, /*isConstant=*/true, llvm::GlobalValue::ExternalLinkage,
-        Init, Name, /*InsertBefore=*/nullptr, llvm::GlobalValue::NotThreadLocal,
-        GlobalAS);
-    GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
-    CGM.addCompilerUsedGlobal(GV);
-    return;
-  }
-
-  // Host side: emit an opaque void* shadow. Layout doesn't matter — the
-  // runtime locates it by name via hipGetSymbolAddress and treats it as
-  // the address of the device-side struct. Registration with the HIP
-  // runtime is added by makeRegisterGlobalsFn (non-RDC) or
-  // createOffloadingEntries (RDC).
-  auto *PtrTy = llvm::PointerType::getUnqual(Ctx);
-  OffloadProfShadow = new llvm::GlobalVariable(
-      M, PtrTy, /*isConstant=*/false, llvm::GlobalValue::ExternalLinkage,
-      llvm::ConstantPointerNull::get(PtrTy), Name);
-  CGM.addCompilerUsedGlobal(OffloadProfShadow);
 }
 
 // Returns module constructor to be added.
 llvm::Function *CGNVCUDARuntime::finalizeModule() {
   transformManagedVars();
-  emitOffloadProfilingSections();
   if (CGM.getLangOpts().CUDAIsDevice) {
     // Mark ODR-used device variables as compiler used to prevent it from being
     // eliminated by optimization. This is necessary for device variables

clang/test/CodeGenHIP/offload-pgo-sections.hip

@@ -322,15 +322,6 @@ option(COMPILER_RT_USE_ATOMIC_LIBRARY "Use compiler-rt atomic instead of libatom
 
 option(COMPILER_RT_PROFILE_BAREMETAL "Build minimal baremetal profile library" OFF)
 
-set(DEFAULT_COMPILER_RT_BUILD_PROFILE_ROCM ON)
-if(APPLE)
-  set(DEFAULT_COMPILER_RT_BUILD_PROFILE_ROCM OFF)
-endif()
-option(COMPILER_RT_BUILD_PROFILE_ROCM
-  "Build the host-side ROCm/HIP device profile collection runtime"
-  ${DEFAULT_COMPILER_RT_BUILD_PROFILE_ROCM})
-mark_as_advanced(COMPILER_RT_BUILD_PROFILE_ROCM)
-
 include(config-ix)
 
 #================================

compiler-rt/CMakeLists.txt

@@ -93,9 +93,6 @@ if (NOT COMPILER_RT_PROFILE_BAREMETAL)
     InstrProfilingUtil.c
     InstrProfilingValue.c
     )
-  if(COMPILER_RT_BUILD_PROFILE_ROCM)
-    list(APPEND PROFILE_SOURCES InstrProfilingPlatformROCm.cpp)
-  endif()
 endif()
 
 set(PROFILE_HEADERS
@@ -158,43 +155,6 @@ if(COMPILER_RT_PROFILE_BAREMETAL)
      -DCOMPILER_RT_PROFILE_BAREMETAL=1)
 endif()
 
-# The HIP host interceptor in InstrProfilingPlatformROCm.cpp pulls in
-# RTInterception + sanitizer_common object libs. Those targets are only created
-# when COMPILER_RT_BUILD_SANITIZERS / _MEMPROF / _XRAY / _CTX_PROFILE is enabled
-# (see lib/CMakeLists.txt). In a profile-only build the targets do not exist;
-# skip both the object-lib merge and the ROCm source file so the static archive
-# remains self-contained.
-set(PROFILE_OBJECT_LIBS)
-set(PROFILE_HAS_HIP_INTERCEPTOR FALSE)
-if(COMPILER_RT_HAS_INTERCEPTION AND NOT COMPILER_RT_PROFILE_BAREMETAL
-   AND TARGET RTInterception.${COMPILER_RT_DEFAULT_TARGET_ARCH}
-   AND TARGET RTSanitizerCommon.${COMPILER_RT_DEFAULT_TARGET_ARCH}
-   AND TARGET RTSanitizerCommonLibc.${COMPILER_RT_DEFAULT_TARGET_ARCH})
-  # RTInterception references __sanitizer_internal_{memcpy,memset,memmove} and other
-  # sanitizer_common symbols; merge the same object libs as clang_rt.cfi (without
-  # coverage/symbolizer) so -fprofile-instr-generate links stay self-contained.
-  list(APPEND PROFILE_OBJECT_LIBS
-    RTInterception
-    RTSanitizerCommon
-    RTSanitizerCommonLibc)
-  set(PROFILE_HAS_HIP_INTERCEPTOR TRUE)
-endif()
-
-if(NOT PROFILE_HAS_HIP_INTERCEPTOR)
-  list(REMOVE_ITEM PROFILE_SOURCES InstrProfilingPlatformROCm.cpp)
-endif()
-
-# Only advertise the ROCm interceptor to InstrProfilingFile.c when its
-# definition (InstrProfilingPlatformROCm.cpp) is actually compiled into the
-# archive. Otherwise InstrProfilingFile.c references
-# __llvm_profile_hip_collect_device_data with no definition; on COFF/Windows
-# there is no weak-undefined fallback, so the link fails (see PR #200111).
-if(COMPILER_RT_BUILD_PROFILE_ROCM AND PROFILE_HAS_HIP_INTERCEPTOR)
-  set(EXTRA_FLAGS
-      ${EXTRA_FLAGS}
-      -DCOMPILER_RT_BUILD_PROFILE_ROCM=1)
-endif()
-
 if("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "amdgcn|nvptx")
   append_list_if(COMPILER_RT_HAS_FFREESTANDING_FLAG -ffreestanding EXTRA_FLAGS)
   append_list_if(COMPILER_RT_HAS_NOGPULIB_FLAG -nogpulib EXTRA_FLAGS)
@@ -208,24 +168,13 @@ if("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "amdgcn|nvptx")
 endif()
 
 if(MSVC)
-  # profile historically used the static CRT (/MT). When we merge RTInterception and
-  # RTSanitizerCommon (same object libs as clang_rt.cfi on ELF), those targets are
-  # built with MultiThreadedDLL (/MD) — see interception/CMakeLists.txt and
-  # sanitizer_common/CMakeLists.txt. Mixing /MD objects into a /MT libclang_rt.profile
-  # yields LNK2019 (__imp__stricmp from interception_win.cpp) and LNK4098 in Profile-*.
-  if(PROFILE_HAS_HIP_INTERCEPTOR)
-    set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreadedDLL)
-  else()
-    set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreaded)
-  endif()
+  # profile historically has only been supported with the static runtime
+  # on windows
+  set(CMAKE_MSVC_RUNTIME_LIBRARY MultiThreaded)
 endif()
 
 # We don't use the C++ Standard Library here, so avoid including it by mistake.
 append_list_if(COMPILER_RT_HAS_NOSTDINCXX_FLAG -nostdinc++ EXTRA_FLAGS)
-# C++ profile sources (e.g. InstrProfilingPlatformROCm.cpp) must not emit exception
-# personality symbols: host libclang_rt.profile.a is linked from C code and from C++
-# tests that do not pull in __gxx_personality_v0 (Profile-* / premerge).
-append_list_if(COMPILER_RT_HAS_FNO_EXCEPTIONS_FLAG -fno-exceptions EXTRA_FLAGS)
 # XRay uses C++ standard library headers.
 string(REGEX REPLACE "-?-stdlib=[a-zA-Z+]*" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
 
@@ -251,7 +200,6 @@ if(APPLE)
     STATIC
     OS ${PROFILE_SUPPORTED_OS}
     ARCHS ${PROFILE_SUPPORTED_ARCH}
-    OBJECT_LIBS ${PROFILE_OBJECT_LIBS}
     CFLAGS ${EXTRA_FLAGS}
     SOURCES ${PROFILE_SOURCES}
     ADDITIONAL_HEADERS ${PROFILE_HEADERS}
@@ -261,7 +209,6 @@ else()
   add_compiler_rt_runtime(clang_rt.profile
     STATIC
     ARCHS ${PROFILE_SUPPORTED_ARCH}
-    OBJECT_LIBS ${PROFILE_OBJECT_LIBS}
     CFLAGS ${EXTRA_FLAGS}
     SOURCES ${PROFILE_SOURCES}
     ADDITIONAL_HEADERS ${PROFILE_HEADERS}