[PATCH] D53736: [BTF] Add BTF DebugInfo

[Yonghong Song via Phabricator via llvm-commits]

yonghong-song added a comment.

@aprantl I just tried. The following is the change which works by using a stub BPFDebug when BPF target is not specified.

  diff --git a/lib/CodeGen/AsmPrinter/BTFDebugStub.cpp b/lib/CodeGen/AsmPrinter/BTFDebugStub.cpp
  new file mode 100644
  index 00000000000..f27e9c5c75f
  --- /dev/null
  +++ b/lib/CodeGen/AsmPrinter/BTFDebugStub.cpp
  @@ -0,0 +1,46 @@
  +//===- llvm/lib/CodeGen/AsmPrinter/BTFDebugStub.cpp -------------*- C++ -*-===//
  +//
  +//                     The LLVM Compiler Infrastructure
  +//
  +// This file is distributed under the University of Illinois Open Source
  +// License. See LICENSE.TXT for details.
  +//
  +//===----------------------------------------------------------------------===//
  +///
  +/// \file
  +/// This file is a stub for BTF generation support. The real implementation
  +/// is at BTFDebug.cpp which will be included if BPF target is built.
  +///
  +//===----------------------------------------------------------------------===//
  +
  +#include "DebugHandlerBase.h"
  +
  +namespace llvm {
  +
  +/// Collect and emit BTF information.
  +class BTFDebug : public DebugHandlerBase {
  +
  +protected:
  +  /// Gather pre-function debug information.
  +  void beginFunctionImpl(const MachineFunction *MF) override {};
  +
  +  /// Post process after all instructions in this function are processed.
  +  void endFunctionImpl(const MachineFunction *MF) override {};
  +
  +public:
  +  BTFDebug(AsmPrinter *AP);
  +
  +  void setSymbolSize(const MCSymbol *Symbol, uint64_t Size) override {}
  +
  +  /// Process beginning of an instruction.
  +  void beginInstruction(const MachineInstr *MI) override {
  +    DebugHandlerBase::beginInstruction(MI);
  +  };
  +
  +  /// Complete all the types and emit the BTF sections.
  +  void endModule() override {};
  +};
  +
  +BTFDebug::BTFDebug(AsmPrinter *AP) : DebugHandlerBase(AP) {}
  +
  +} // end namespace llvm
  diff --git a/lib/CodeGen/AsmPrinter/CMakeLists.txt b/lib/CodeGen/AsmPrinter/CMakeLists.txt
  index 24c5d33a120..e12fbf92c77 100644
  --- a/lib/CodeGen/AsmPrinter/CMakeLists.txt
  +++ b/lib/CodeGen/AsmPrinter/CMakeLists.txt
  @@ -1,3 +1,14 @@
  +# depends on whether BPF target is built or not
  +# eitheer BTFDebug.cpp or BTFDebugStub.cpp is included,
  +# but not both.
  +set(LLVM_OPTIONAL_SOURCES "BTFDebug.cpp" "BTFDebugStub.cpp")
  +list(FIND LLVM_TARGETS_TO_BUILD "BPF" idx)
  +if( NOT idx LESS 0 )
  +set(BTFDebug_File "BTFDebug.cpp")
  +else()
  +set(BTFDebug_File "BTFDebugStub.cpp")
  +endif()
  +
   add_llvm_library(LLVMAsmPrinter
     AccelTable.cpp
     AddressPool.cpp
  @@ -24,7 +35,7 @@ add_llvm_library(LLVMAsmPrinter
     WinException.cpp
     CodeViewDebug.cpp
     WasmException.cpp
  -  BTFDebug.cpp
  +  ${BTFDebug_File}
   
     DEPENDS
     intrinsics_gen

This adds complexity to make file and it adds one more file BTFDebugStub.cpp. I personally think this is not a good approach.
But please let me know what you think and I can implement this if you think it is good.


Repository:
  rL LLVM

https://reviews.llvm.org/D53736