sparc64 segfault with function returning an empty struct

[arndb]

Bugzilla Link	41439
Version	8.0
OS	Linux
Blocks	#4440
CC	@nickdesaulniers

Extended Description

Attempting to build a sparc64 linux kernel with clang, I ran into a segmentation fault compiling mm/mmap.c. Reduced the test case to

struct vm_userfaultfd_ctx {
} fn1(struct vm_userfaultfd_ctx p1) {
return p1;
}

$ clang-9 -cc1 mmap.c -triple sparc64-unknown-linux-gnu -S
Stack dump:
0. Program arguments: clang-9 -cc1 mmap-f2e46f.c -triple sparc64-unknown-linux-gnu -S

1. parser at end of file
2. mmap-f2e46f.c:2:3: LLVM IR generation of declaration 'fn1'
3. mmap-f2e46f.c:2:3: Generating code for declaration 'fn1'
   #​0 0x00007f8be972b97f llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/usr/lib/x86_64-linux-gnu/libLLVM-9.so.1+0x96d97f)
   #​1 0x00007f8be9729dd0 llvm::sys::RunSignalHandlers() (/usr/lib/x86_64-linux-gnu/libLLVM-9.so.1+0x96bdd0)
   #​2 0x00007f8be972bd88 (/usr/lib/x86_64-linux-gnu/libLLVM-9.so.1+0x96dd88)
   #​3 0x00007f8bec979390 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x11390)
   #​4 0x000000000087982d (clang-9+0x87982d)
   #​5 0x000000000076836a (clang-9+0x76836a)
   #​6 0x000000000076984f (clang-9+0x76984f)
   #​7 0x0000000000780b8b (clang-9+0x780b8b)
   #​8 0x000000000077a90b (clang-9+0x77a90b)
   #​9 0x0000000000783072 (clang-9+0x783072)
   #​10 0x0000000000d70c3f (clang-9+0xd70c3f)
   #​11 0x0000000000d6e572 (clang-9+0xd6e572)
   #​12 0x00000000011f2c33 (clang-9+0x11f2c33)
   #​13 0x0000000000af751f (clang-9+0xaf751f)
   #​14 0x0000000000ab7878 (clang-9+0xab7878)
   #​15 0x0000000000b7c895 (clang-9+0xb7c895)
   #​16 0x00000000006b140c (clang-9+0x6b140c)
   #​17 0x00000000006af97f (clang-9+0x6af97f)
   #​18 0x00007f8be8167830 __libc_start_main /build/glibc-LK5gWL/glibc-2.23/csu/../csu/libc-start.c:325:0
   #​19 0x00000000006ad0d9 (clang-9+0x6ad0d9)
   Segmentation fault (core dumped)

[Endilll]

Still crashing as of post-17 trunk: https://godbolt.org/z/YTM68b4Yo

clang++: /root/llvm-project/llvm/include/llvm/IR/Function.h:795:
llvm::Argument* llvm::Function::getArg(unsigned int) const:
Assertion `i < NumArgs && "getArg() out of range!"' failed.

PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -x c -Wno-implicit-int -Wno-implicit-function-declaration -target sparc64-unknown-linux-gnu <source>
1.	<eof> parser at end of file
2.	<source>:2:3: LLVM IR generation of declaration 'fn1'
3.	<source>:2:3: Generating code for declaration 'fn1'
 #0 0x00000000036aeb98 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x36aeb98)
 #1 0x00000000036ac85c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x36ac85c)
 #2 0x00000000035f5c88 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f27702d9420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007f276fd9c00b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #5 0x00007f276fd7b859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #6 0x00007f276fd7b729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
 #7 0x00007f276fd8cfd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #8 0x0000000003d3bfdb clang::CodeGen::CodeGenFunction::EmitFunctionProlog(clang::CodeGen::CGFunctionInfo const&, llvm::Function*, clang::CodeGen::FunctionArgList const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3d3bfdb)
 #9 0x0000000003a3bb54 clang::CodeGen::CodeGenFunction::StartFunction(clang::GlobalDecl, clang::QualType, llvm::Function*, clang::CodeGen::CGFunctionInfo const&, clang::CodeGen::FunctionArgList const&, clang::SourceLocation, clang::SourceLocation) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a3bb54)
#10 0x0000000003a40ba1 clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a40ba1)
#11 0x0000000003aa1fc3 clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3aa1fc3)
#12 0x0000000003a9d0b5 clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a9d0b5)
#13 0x0000000003a9d67b clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3a9d67b)
#14 0x0000000003aa6af3 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) (.part.0) CodeGenModule.cpp:0:0
#15 0x00000000049117b6 (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) ModuleBuilder.cpp:0:0
#16 0x00000000049023c8 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49023c8)
#17 0x0000000005e03784 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5e03784)
#18 0x000000000490e668 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x490e668)
#19 0x0000000004176d59 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4176d59)
#20 0x00000000040f6f7e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x40f6f7e)
#21 0x0000000004254fce clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4254fce)
#22 0x0000000000bd6e70 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xbd6e70)
#23 0x0000000000bcf09a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#24 0x0000000003f582e9 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
#25 0x00000000035f6134 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x35f6134)
#26 0x0000000003f588df 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
#27 0x0000000003f20c65 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f20c65)
#28 0x0000000003f216cd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f216cd)
#29 0x0000000003f295f5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f295f5)
#30 0x0000000000bd4c7c clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xbd4c7c)
#31 0x0000000000ad1481 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xad1481)
#32 0x00007f276fd7d083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#33 0x0000000000bceb7e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xbceb7e)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)

[llvmbot]

@llvm/issue-subscribers-clang-codegen