…StrictPackMatch field (llvm#126215)

This addresses the MSAN failure reported
in
llvm#125791 (comment):
```
==5633==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 in clang::ASTNodeImporter::CallOverloadedCreateFun<clang::ClassTemplateSpecializationDecl>::operator()
    #1 in bool clang::ASTNodeImporter::GetImportedOrCreateSpecialDecl<...>
...
```

The ASTImporter reads `D->hasStrictPackMatch()` and forwards it to the
constructor of the destination `ClassTemplateSpecializationDecl`. But if
`D` is a decl that LLDB created from debug-info, it would've been
created using `ClassTemplateSpecializationDecl::CreateDeserialized`,
which doesn't initialize the `StrictPackMatch` field.

This patch just initializes the field to a fixed value of `false`, to
preserve previous behaviour and avoid the use-of-uninitialized-value.

An alternative would be to always initialize it in the
`ClassTemplateSpecializationDecl` constructor, but there were
reservations about providing a default value for it because it might
lead to hard-to-diagnose problems down the line.

We can't guaranty that underlying string is
0-terminated and [String.size()] is even in the
same allocation.


https://lab.llvm.org/buildbot/#/builders/94/builds/4152/steps/17/logs/stdio
```
==c-index-test==1846256==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0  in clang::cxstring::createRef(llvm::StringRef) llvm-project/clang/tools/libclang/CXString.cpp:96:36
    #1  in DumpCXCommentInternal llvm-project/clang/tools/c-index-test/c-index-test.c:521:39
    llvm#2  in DumpCXCommentInternal llvm-project/clang/tools/c-index-test/c-index-test.c:674:7
    llvm#3  in DumpCXCommentInternal llvm-project/clang/tools/c-index-test/c-index-test.c:674:7
    llvm#4  in DumpCXComment llvm-project/clang/tools/c-index-test/c-index-test.c:685:3
    llvm#5  in PrintCursorComments llvm-project/clang/tools/c-index-test/c-index-test.c:768:7

  Memory was marked as uninitialized
    #0  in __msan_allocated_memory llvm-project/compiler-rt/lib/msan/msan_interceptors.cpp:1023:5
    #1  in Allocate llvm-project/llvm/include/llvm/Support/Allocator.h:172:7
    llvm#2  in Allocate llvm-project/llvm/include/llvm/Support/Allocator.h:216:12
    llvm#3  in Allocate llvm-project/llvm/include/llvm/Support/AllocatorBase.h:53:43
    llvm#4  in Allocate<char> llvm-project/llvm/include/llvm/Support/AllocatorBase.h:76:29
    llvm#5  in convertCodePointToUTF8 llvm-project/clang/lib/AST/CommentLexer.cpp:42:30
    llvm#6  in clang::comments::Lexer::resolveHTMLDecimalCharacterReference(llvm::StringRef) const llvm-project/clang/lib/AST/CommentLexer.cpp:76:10
    llvm#7  in clang::comments::Lexer::lexHTMLCharacterReference(clang::comments::Token&) llvm-project/clang/lib/AST/CommentLexer.cpp:615:16
    llvm#8  in consumeToken llvm-project/clang/include/clang/AST/CommentParser.h:62:9
    llvm#9  in clang::comments::Parser::parseParagraphOrBlockCommand() llvm-project/clang/lib/AST/CommentParser.cpp
    llvm#10 in clang::comments::Parser::parseFullComment() llvm-project/clang/lib/AST/CommentParser.cpp:925:22
    llvm#11 in clang::RawComment::parse(clang::ASTContext const&, clang::Preprocessor const*, clang::Decl const*) const llvm-project/clang/lib/AST/RawCommentList.cpp:221:12
    llvm#12 in clang::ASTContext::getCommentForDecl(clang::Decl const*, clang::Preprocessor const*) const llvm-project/clang/lib/AST/ASTContext.cpp:714:35
    llvm#13 in clang_Cursor_getParsedComment llvm-project/clang/tools/libclang/CXComment.cpp:36:35
    llvm#14 in PrintCursorComments llvm-project/clang/tools/c-index-test/c-index-test.c:756:25
 ```

… without debug-info" (llvm#137757)

Reverts llvm#137408

This change broke `lldb/test/Shell/Unwind/split-machine-functions.test`.

The test binary has a symbol named `_Z3foov.cold` and the test expects
the backtrace to print the name of the cold part of the function like
this:

```
# SPLIT: frame #1: {{.*}}`foo() (.cold) +
```
but now it gets

```
frame #1: 0x000055555555514f split-machine-functions.test.tmp`foo() + 12
```

…gger memory is updated (llvm#129092)"

This reverts commit daa4061.

Original PR llvm#129092.

I have restricted the test to X86 Windows because it turns out the only
reason that `expr x.get()` would change m_memory_id is that on x86 we
have to write the return address to the stack in ABIWindows_X86_64::PrepareTrivialCall:
```
  // Save return address onto the stack
  if (!process_sp->WritePointerToMemory(sp, return_addr, error))
    return false;
```

This is not required on AArch64 so m_memory_id was not changed:
```
(lldb) expr x.get()
(int) $0 = 0
(lldb) process status -d
Process 15316 stopped
* thread #1, stop reason = Exception 0x80000003 encountered at address 0x7ff764a31034
    frame #0: 0x00007ff764a31038 TestProcessModificationIdOnExpr.cpp.tmp`main at TestProcessModificationIdOnExpr.cpp:35
   32     __builtin_debugtrap();
   33     __builtin_debugtrap();
   34     return 0;
-> 35   }
   36
   37   // CHECK-LABEL: process status -d
   38   // CHECK: m_stop_id: 2
ProcessModID:
  m_stop_id: 3
  m_last_natural_stop_id: 0
  m_resume_id: 0
  m_memory_id: 0
```

Really we should find a better way to force a memory write here, but
I can't think of one right now.

we already check for `platform_sp` not null in one line below. 

existing code
```
if (platform_sp) {
      Status error;
      if (platform_sp) {
...
...
     }
}
```

`platform_sp` null check is redundant and error variable is unused. 

### TEST PLAN 
manual test 

```
satyajanga@devvm21837:toolchain $ ./bin/lldb
LLDB logging initialized. Logs stored in: /tmp
(lldb) platform select host
  Platform: host
    Triple: x86_64-*-linux-gnu
OS Version: 6.9.0 (6.9.0-0_fbk5_hardened_1_gf368ae920c1a)
  Hostname: 127.0.0.1
WorkingDir: /home/satyajanga/llvm-sand/build/Debug/fbcode-x86_64/toolchain
    Kernel: #1 SMP Tue Feb 11 07:24:41 PST 2025
    Kernel: Linux
   Release: 6.9.0-0_fbk5_hardened_1_gf368ae920c1a
   Version: #1 SMP Tue Feb 11 07:24:41 PST 2025
(lldb) platform process list
144 matching processes were found on "host"

PID    PARENT USER       TRIPLE                         NAME
====== ====== ========== ============================== ============================
130461 874915 satyajanga x86_64-*-linux-gnu             sushd
135505 874915 satyajanga x86_64-*-linux-gnu             hg.real
817146 874915 satyajanga x86_64-*-linux-gnu             vscode-thrift
874915 1      satyajanga                                
874947 874915 satyajanga                                
```

and running the existing tests
```
satyajanga@devvm21837:toolchain $ ./bin/llvm-lit -v  ~/llvm-sand/external/llvm-project/lldb/test/API/commands/platform/
-- Testing: 9 tests, 9 workers --
PASS: lldb-api :: commands/platform/file/read/TestPlatformFileRead.py (1 of 9)
PASS: lldb-api :: commands/platform/file/close/TestPlatformFileClose.py (2 of 9)
UNSUPPORTED: lldb-api :: commands/platform/sdk/TestPlatformSDK.py (3 of 9)
PASS: lldb-api :: commands/platform/basic/TestPlatformPython.py (4 of 9)
PASS: lldb-api :: commands/platform/basic/TestPlatformCommand.py (5 of 9)
PASS: lldb-api :: commands/platform/connect/TestPlatformConnect.py (6 of 9)
PASS: lldb-api :: commands/platform/process/launch/TestPlatformProcessLaunch.py (7 of 9)
PASS: lldb-api :: commands/platform/launchgdbserver/TestPlatformLaunchGDBServer.py (8 of 9)
PASS: lldb-api :: commands/platform/process/list/TestProcessList.py (9 of 9)

Testing Time: 13.48s

Total Discovered Tests: 9
  Unsupported: 1 (11.11%)
  Passed     : 8 (88.89%)
satyajanga@devvm21837:toolchain $ 
```

llvm#138091)

Check this error for more context
(https://github.com/compiler-research/CppInterOp/actions/runs/14749797085/job/41407625681?pr=491#step:10:531)

This fails with 
```
* thread #1, name = 'CppInterOpTests', stop reason = signal SIGSEGV: address not mapped to object (fault address: 0x55500356d6d3)
  * frame #0: 0x00007fffee41cfe3 libclangCppInterOp.so.21.0gitclang::PragmaNamespace::~PragmaNamespace() + 99
    frame #1: 0x00007fffee435666 libclangCppInterOp.so.21.0gitclang::Preprocessor::~Preprocessor() + 3830
    frame llvm#2: 0x00007fffee20917a libclangCppInterOp.so.21.0gitstd::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() + 58
    frame llvm#3: 0x00007fffee224796 libclangCppInterOp.so.21.0gitclang::CompilerInstance::~CompilerInstance() + 838
    frame llvm#4: 0x00007fffee22494d libclangCppInterOp.so.21.0gitclang::CompilerInstance::~CompilerInstance() + 13
    frame llvm#5: 0x00007fffed95ec62 libclangCppInterOp.so.21.0gitclang::IncrementalCUDADeviceParser::~IncrementalCUDADeviceParser() + 98
    frame llvm#6: 0x00007fffed9551b6 libclangCppInterOp.so.21.0gitclang::Interpreter::~Interpreter() + 102
    frame llvm#7: 0x00007fffed95598d libclangCppInterOp.so.21.0gitclang::Interpreter::~Interpreter() + 13
    frame llvm#8: 0x00007fffed9181e7 libclangCppInterOp.so.21.0gitcompat::createClangInterpreter(std::vector<char const*, std::allocator<char const*>>&) + 2919
```

Problem : 

1) The destructor currently handles no clearance for the DeviceParser
and the DeviceAct. We currently only have this

https://github.com/llvm/llvm-project/blob/976493822443c52a71ed3c67aaca9a555b20c55d/clang/lib/Interpreter/Interpreter.cpp#L416-L419

2) The ownership for DeviceCI currently is present in
IncrementalCudaDeviceParser. But this should be similar to how the
combination for hostCI, hostAction and hostParser are managed by the
Interpreter. As on master the DeviceAct and DeviceParser are managed by
the Interpreter but not DeviceCI. This is problematic because :
IncrementalParser holds a Sema& which points into the DeviceCI. On
master, DeviceCI is destroyed before the base class ~IncrementalParser()
runs, causing Parser::reset() to access a dangling Sema (and as Sema
holds a reference to Preprocessor which owns PragmaNamespace) we see
this
```
  * frame #0: 0x00007fffee41cfe3 libclangCppInterOp.so.21.0gitclang::PragmaNamespace::~PragmaNamespace() + 99
    frame #1: 0x00007fffee435666 libclangCppInterOp.so.21.0gitclang::Preprocessor::~Preprocessor() + 3830
    
```

When running the `openmp` testsuite on Solaris/amd64, many tests `FAIL`
like

```
# | OMP: Error llvm#11: Stack overflow detected for OpenMP thread #1
```

In a `Debug` build, I also get
```
# | Assertion failure at kmp_runtime.cpp(203): __kmp_gtid_get_specific() < 0 || __kmp_gtid_get_specific() == i.
```

Further investigation shows that just setting `__kmp_gtid_mode` to 3
massively reduces the number of failures.

Tested on `amd64-pc-solaris2.11` and `x86_64-pc-linux-gnu`.

Fix for:
`Assertion failed: (false && "Architecture or OS not supported"),
function CreateRegisterContextForFrame, file
/usr/src/contrib/llvm-project/lldb/source/Plugins/Process/elf-core/ThreadElfCore.cpp,
line 182.
PLEASE submit a bug report to https://bugs.freebsd.org/submit/ and
include the crash backtrace.
#0 0x000000080cd857c8 llvm::sys::PrintStackTrace(llvm::raw_ostream&,
int)
/usr/src/contrib/llvm-project/llvm/lib/Support/Unix/Signals.inc:723:13
#1 0x000000080cd85ed4
/usr/src/contrib/llvm-project/llvm/lib/Support/Unix/Signals.inc:797:3
llvm#2 0x000000080cd82ae8 llvm::sys::RunSignalHandlers()
/usr/src/contrib/llvm-project/llvm/lib/Support/Signals.cpp:104:5
llvm#3 0x000000080cd861f0 SignalHandler
/usr/src/contrib/llvm-project/llvm/lib/Support/Unix/Signals.inc:403:3 llvm#4
0x000000080f159644 handle_signal
/usr/src/lib/libthr/thread/thr_sig.c:298:3
`

The mcmodel=tiny memory model is only valid on ARM targets. While trying
this on X86 compiler throws an internal error along with stack dump.
llvm#125641
This patch resolves the issue.
Reduced test case:
```
#include <stdio.h>
int main( void )
{
printf( "Hello, World!\n" ); 
return 0; 
}
```
```
0.	Program arguments: /opt/compiler-explorer/clang-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -mcmodel=tiny <source>
1.	<eof> parser at end of file
 #0 0x0000000003b10218 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b10218)
 #1 0x0000000003b0e35c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b0e35c)
 llvm#2 0x0000000003a5dbc3 llvm::CrashRecoveryContext::HandleExit(int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a5dbc3)
 llvm#3 0x0000000003b05cfe llvm::sys::Process::Exit(int, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3b05cfe)
 llvm#4 0x0000000000d4e3eb LLVMErrorHandler(void*, char const*, bool) cc1_main.cpp:0:0
 llvm#5 0x0000000003a67c93 llvm::report_fatal_error(llvm::Twine const&, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a67c93)
 llvm#6 0x0000000003a67df8 (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a67df8)
 llvm#7 0x0000000002549148 llvm::X86TargetMachine::X86TargetMachine(llvm::Target const&, llvm::Triple const&, llvm::StringRef, llvm::StringRef, llvm::TargetOptions const&, std::optional<llvm::Reloc::Model>, std::optional<llvm::CodeModel::Model>, llvm::CodeGenOptLevel, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x2549148)
 llvm#8 0x00000000025491fc llvm::RegisterTargetMachine<llvm::X86TargetMachine>::Allocator(llvm::Target const&, llvm::Triple const&, llvm::StringRef, llvm::StringRef, llvm::TargetOptions const&, std::optional<llvm::Reloc::Model>, std::optional<llvm::CodeModel::Model>, llvm::CodeGenOptLevel, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x25491fc)
 llvm#9 0x0000000003db74cc clang::emitBackendOutput(clang::CompilerInstance&, clang::CodeGenOptions&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3db74cc)
llvm#10 0x0000000004460d95 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4460d95)
llvm#11 0x00000000060005ec clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x60005ec)
llvm#12 0x00000000044614b5 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x44614b5)
llvm#13 0x0000000004737121 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4737121)
llvm#14 0x00000000046b777b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x46b777b)
llvm#15 0x00000000048229e3 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x48229e3)
llvm#16 0x0000000000d50621 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd50621)
llvm#17 0x0000000000d48e2d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
llvm#18 0x00000000044acc99 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
llvm#19 0x0000000003a5dac3 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3a5dac3)
llvm#20 0x00000000044aceb9 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
llvm#21 0x00000000044710dd clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x44710dd)
llvm#22 0x0000000004472071 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4472071)
llvm#23 0x000000000447c3fc clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x447c3fc)
llvm#24 0x0000000000d4d2b1 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd4d2b1)
llvm#25 0x0000000000c12464 main (/opt/compiler-explorer/clang-trunk/bin/clang+++0xc12464)
llvm#26 0x00007ae43b029d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
llvm#27 0x00007ae43b029e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
llvm#28 0x0000000000d488c5 _start (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd488c5)
```

---------

Co-authored-by: Shashwathi N <[email protected]>