lldb crash for "x86_64-w64-windows-gnu" because of architecture triple mismatch - solution proposition

[llvmbot]

Bugzilla Link	51433
Version	12.0
OS	Windows NT
Attachments	the crash backtrace
Reporter	LLVM Bugzilla Contributor
CC	@cristianadam,@JDevlieghere

Extended Description

The problem concerns the 64bit lldb (12.0.01 and 14.0.0) debugger compiled for "x86_64-w64-windows-gnu".
The debugger crashes if a variable of type class method pointer is examined.
Debugging of the lldb shown the problem is a result of the architecture "triple" mismatch, and a difference in the implementation of class method pointers between "msvc" and "gnu".
The triplet lldb for debugged exe file obtains the by method "ObjectFilePECOFF::GetModuleSpecifications"
and sets it to "x86_64-pc-windows". Finally the triplet is transformed to ""x86_64-pc-windows.msvc" by Triple::normalize at the clang side.

It seems to be reasonable to resolve the problem at its origin, by replacing the wrong hard coded triple value, in "ObjectFilePECOFF:: GetModuleSpecifications" to the proper one, by using some additional criteria.

Here is the patch:

diff --git a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
index 9eb1c25d2403..61550682a019 100644
--- a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
+++ b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
@@ -32,6 +32,7 @@
#include "llvm/Object/COFFImportFile.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Host.h"

#define IMAGE_DOS_SIGNATURE 0x5A4D // MZ
#define IMAGE_NT_SIGNATURE 0x00004550 // PE00
@@ -163,7 +164,10 @@ size_t ObjectFilePECOFF::GetModuleSpecifications(

switch (COFFObj->getMachine()) {
case MachineAmd64:

• spec.SetTriple("x86_64-pc-windows");

•   if(llvm::sys::getProcessTriple()=="x86_64-w64-windows-gnu")
  

•           spec.SetTriple("x86_64-w64-windows-gnu");
  

•   else
  

•           spec.SetTriple("x86_64-pc-windows");
  

  specs.Append(module_spec);
  break;
  case MachineX86:

[cristianadam]

I've got a similar crash with LLVM-MinGW 13.0.0 RC1
mstorsjo/llvm-mingw#226

Crash stacktrace:

eERROR: Lldb stderr: #​0 0x00007ffab4913933 clang::CreateMicrosoftCXXABI(clang::ASTContext&) (C:\llvm-mingw\bin\libclang-cpp.dll+0x563933)
e #​1 0x00007ffab45e0e95 clang::ASTContext::getTypeInfoImpl(clang::Type const*) const (C:\llvm-mingw\bin\libclang-cpp.dll+0x230e95)
e #​2 0x00007ffab45e225b clang::ASTContext::getTypeInfo(clang::Type const*) const (C:\llvm-mingw\bin\libclang-cpp.dll+0x23225b)
e #​3 0x00007ffadae4e17a PyInit__lldb (C:\llvm-mingw\bin\liblldb.dll+0x6be17a)

[alvinhochun]

See https://reviews.llvm.org/D127048