[clang] [Modules] No transitive source location change (PR #86912)

[Rainer Orth via cfe-commits]

rorth wrote:

> I'll revert this. Due to I can't reproduce this. When the bot gets stable, please tell if it is the real problem.

You can reproduce this: the [GCC compile farm](https://portal.cfarm.net/) does have a Solaris/sparcv9 system (`cfarm215`) which is perfectly equipped to run LLVM builds (I've tried).

I think the stack traces from the bot are a pretty strong indication that your patch is the culprit:
```
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  clang-19  0x00000001076d87b8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 36
1  clang-19  0x00000001076d910c SignalHandler(int) + 896
2  libc.so.1 0x00007fffff0c62a8 __sighndlr + 12
3  libc.so.1 0x00007fffff0b8b50 call_user_handler + 1024
4  libc.so.1 0x00007fffff0b8f10 sigacthandler + 160
5  clang-19  0x00000001083824e0 clang::ASTReader::DeclCursorForID(clang::GlobalDeclID, clang::SourceLocation&) + 168
6  clang-19  0x000000010838aca0 clang::ASTReader::ReadDeclRecord(clang::GlobalDeclID) + 48
7  clang-19  0x00000001082fb4ec clang::ASTReader::GetDecl(clang::GlobalDeclID) + 232
8  clang-19  0x00000001082cb820 clang::ASTReader::SetGloballyVisibleDecls(clang::IdentifierInfo*, llvm::SmallVectorImpl<clang::GlobalDeclID> const&, llvm::SmallVectorImpl<clang::Decl*>*) + 252
9  clang-19  0x00000001083144a0 clang::ASTReader::finishPendingActions() + 572
10 clang-19  0x0000000108319e10 clang::ASTReader::FinishedDeserializing() + 92
11 clang-19  0x000000010830dbf4 clang::ASTReader::get(llvm::StringRef) + 680
12 clang-19  0x00000001078a84fc clang::IdentifierTable::get(llvm::StringRef) + 84
13 clang-19  0x000000010a130fcc clang::Sema::Initialize() + 1208
14 clang-19  0x0000000109fd1814 clang::Parser::Initialize() + 1260
15 clang-19  0x0000000109fccb68 clang::ParseAST(clang::Sema&, bool, bool) + 556
16 clang-19  0x00000001081b10d8 clang::ASTFrontendAction::ExecuteAction() + 248
17 clang-19  0x00000001081b06f8 clang::FrontendAction::Execute() + 92
18 clang-19  0x00000001081196c8 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 1572
19 clang-19  0x00000001082b87b8 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 684
20 clang-19  0x00000001048a2980 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 4296
21 clang-19  0x000000010489f6f8 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) + 1184
22 clang-19  0x000000010489e018 clang_main(int, char**, llvm::ToolContext const&) + 4424
23 clang-19  0x00000001048aee0c main + 60
24 clang-19  0x000000010489c904 _start + 100
/var/llvm/dist-sparcv9-release-stage2-A-flang-clang18/tools/clang/stage2-bins/tools/clang/test/PCH/Output/opencl-extensions.cl.script: line 2: 12701 Bus Error               /var/llvm/dist-sparcv9-release-stage2-A-flang-clang18/tools/clang/stage2-bins/bin/clang -cc1 -internal-isystem /var/llvm/dist-sparcv9-release-stage2-A-flang-clang18/tools/clang/stage2-bins/lib/clang/19/include -nostdsysteminc -include-pch /var/llvm/dist-sparcv9-release-stage2-A-flang-clang18/tools/clang/stage2-bins/tools/clang/test/PCH/Output/opencl-extensions.cl.tmp -fsyntax-only /vol/llvm/src/llvm-project/dist/clang/test/PCH/opencl-extensions.cl -triple spir-unknown-unknown
```
One thing I see immediately that this uses a triple the bot is not configured to handle.  Nonetheless clang shouldn't die with `SIGBUS` in such as case.

https://github.com/llvm/llvm-project/pull/86912