[clang] [Clang] Loop over FieldDecls instead of all Decls (PR #99574)

Mon Jul 22 16:11:35 PDT 2024

bwendling wrote:

+Eli Friedman ***@***.***>

I'm confused by what's going on. Here's a shorter testcase:

struct a {};

struct c {
  int done;
  struct a x;
};

struct b {
  struct a y;
  int s;
  int x[] __attribute__((counted_by(s)));
};

int foo(struct b *p, int idx) {
  return __builtin_dynamic_object_size(p, 0);
}

The CGRecordLayout doesn't have 'y' listed as a field. It shows 's' and
'x', but not 'y'... Yet the RecordDecl *does* have 'y' as a FieldDecl. My
only guess is that, because it's an empty struct, the
CGRecordLayout decides that it doesn't need to count it as part of the
record layout? That doesn't make a whole lot of sense to me. I realize that
it has zero size (in C), but I thought we'd still have to deal with it......

Eli, does that make any sense?

-bw

On Mon, Jul 22, 2024 at 5:00 PM Bill Wendling ***@***.***> wrote:

> Okay. I'll look into it.
>
> On Sun, Jul 21, 2024 at 4:35 PM Nathan Chancellor <
> ***@***.***> wrote:
>
>> I see a crash in drivers/thermal/thermal_core.c in Linux kernels without
>> commit daeeb032f42d
>> <https://git.kernel.org/linus/daeeb032f42d066a49e07b7f6effc9f51b7a5479>
>> ("thermal: core: Move threshold out of struct thermal_trip") after this
>> change. cvise spits out:
>>
>> struct swait_queue_head {};struct completion {
>>   int done;
>>   struct swait_queue_head wait;
>> };struct {
>>   struct completion removal;
>>   int num_trips;
>>   int trips[] __attribute__((__counted_by__(num_trips)));
>> } *thermal_zone_device_register_with_trips_tz;int thermal_zone_device_register_with_trips() {
>>   if (thermal_zone_device_register_with_trips_tz)
>>     goto free_tz;
>>   if (0)
>>     goto free_tzp;
>>   {
>>     long __p_size_field = __builtin_dynamic_object_size(
>>         thermal_zone_device_register_with_trips_tz, 1);
>>     _Bool __ret_do_once = __p_size_field, __ret_cond = __ret_do_once;
>>     static _Bool __already_done;
>>     if (__builtin_expect(__ret_cond && __already_done, 0))
>>       ;
>>   }
>> free_tzp:
>> free_tz:
>>   return 0;
>> }
>>
>> $ clang -c -o /dev/null thermal_core.i
>> clang: /home/nathan/tmp/cvise.YrEYUS5WBZ/src/clang/lib/CodeGen/CGRecordLayout.h:200: unsigned int clang::CodeGen::CGRecordLayout::getLLVMFieldNo(const FieldDecl *) const: Assertion `FieldInfo.count(FD) && "Invalid field for record!"' 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: clang -c -o /dev/null thermal_core.i
>> 1.	<eof> parser at end of file
>> 2.	thermal_core.i:11:5: LLVM IR generation of declaration 'thermal_zone_device_register_with_trips'
>> 3.	thermal_core.i:11:5: Generating code for declaration 'thermal_zone_device_register_with_trips'
>> 4.	thermal_core.i:16:3: LLVM IR generation of compound statement ('{}')
>>  #0 0x00005585369d0446 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x55fc446)
>>  #1 0x00005585369cdf0e llvm::sys::RunSignalHandlers() (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x55f9f0e)
>>  #2 0x00005585369513ad CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
>>  #3 0x00007f3d209bdae0 (/usr/lib/libc.so.6+0x3cae0)
>>  #4 0x00007f3d20a15e44 (/usr/lib/libc.so.6+0x94e44)
>>  #5 0x00007f3d209bda30 raise (/usr/lib/libc.so.6+0x3ca30)
>>  #6 0x00007f3d209a54c3 abort (/usr/lib/libc.so.6+0x244c3)
>>  #7 0x00007f3d209a53df (/usr/lib/libc.so.6+0x243df)
>>  #8 0x00007f3d209b5c67 (/usr/lib/libc.so.6+0x34c67)
>>  #9 0x0000558536de6281 clang::CodeGen::CGRecordLayout::getLLVMFieldNo(clang::FieldDecl const*) const CGExpr.cpp:0:0
>> #10 0x0000558536dcd526 getGEPIndicesToField(clang::CodeGen::CodeGenFunction&, clang::RecordDecl const*, clang::FieldDecl const*, llvm::SmallVector<std::pair<clang::RecordDecl const*, llvm::Value*>, 8u>&) CGExpr.cpp:0:0
>> #11 0x0000558536dcd581 getGEPIndicesToField(clang::CodeGen::CodeGenFunction&, clang::RecordDecl const*, clang::FieldDecl const*, llvm::SmallVector<std::pair<clang::RecordDecl const*, llvm::Value*>, 8u>&) CGExpr.cpp:0:0
>> #12 0x0000558536dca542 clang::CodeGen::CodeGenFunction::EmitCountedByFieldExpr(clang::Expr const*, clang::FieldDecl const*, clang::FieldDecl const*) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x59f6542)
>> #13 0x0000558536fb0927 clang::CodeGen::CodeGenFunction::emitFlexibleArrayMemberSize(clang::Expr const*, unsigned int, llvm::IntegerType*) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5bdc927)
>> #14 0x0000558536fafdf8 clang::CodeGen::CodeGenFunction::emitBuiltinObjectSize(clang::Expr const*, unsigned int, llvm::IntegerType*, llvm::Value*, bool) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5bdbdf8)
>> #15 0x0000558536fb9cfc clang::CodeGen::CodeGenFunction::EmitBuiltinExpr(clang::GlobalDecl, unsigned int, clang::CallExpr const*, clang::CodeGen::ReturnValueSlot) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5be5cfc)
>> #16 0x0000558536de827c clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*, clang::CodeGen::ReturnValueSlot) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5a1427c)
>> #17 0x0000558536e024cb (anonymous namespace)::ScalarExprEmitter::VisitCallExpr(clang::CallExpr const*) CGExprScalar.cpp:0:0
>> #18 0x0000558536dee27b (anonymous namespace)::ScalarExprEmitter::Visit(clang::Expr*) CGExprScalar.cpp:0:0
>> #19 0x0000558536e0bedd (anonymous namespace)::ScalarExprEmitter::VisitCastExpr(clang::CastExpr*) CGExprScalar.cpp:0:0
>> #20 0x0000558536dee11c clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5a1a11c)
>> #21 0x0000558536e301e4 clang::CodeGen::CodeGenFunction::EmitScalarInit(clang::Expr const*, clang::ValueDecl const*, clang::CodeGen::LValue, bool) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5a5c1e4)
>> #22 0x0000558536e335d1 clang::CodeGen::CodeGenFunction::EmitAutoVarInit(clang::CodeGen::CodeGenFunction::AutoVarEmission const&) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5a5f5d1)
>> #23 0x0000558536e2da7d clang::CodeGen::CodeGenFunction::EmitVarDecl(clang::VarDecl const&) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5a59a7d)
>> #24 0x0000558536e2d4b7 clang::CodeGen::CodeGenFunction::EmitDecl(clang::Decl const&) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5a594b7)
>> #25 0x0000558536d66ddb clang::CodeGen::CodeGenFunction::EmitDeclStmt(clang::DeclStmt const&) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5992ddb)
>> #26 0x0000558536d59acb clang::CodeGen::CodeGenFunction::EmitSimpleStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5985acb)
>> #27 0x0000558536d58b33 clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5984b33)
>> #28 0x0000558536d59aa1 clang::CodeGen::CodeGenFunction::EmitSimpleStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5985aa1)
>> #29 0x0000558536d58b33 clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5984b33)
>> #30 0x0000558536d67f40 clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5993f40)
>> #31 0x0000558536d44ee6 clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5970ee6)
>> #32 0x0000558536bfb47b clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x582747b)
>> #33 0x0000558536bf2a75 clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x581ea75)
>> #34 0x0000558536bf7a1a clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5823a1a)
>> #35 0x0000558536bf13e2 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x581d3e2)
>> #36 0x0000558537240fbc (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) ModuleBuilder.cpp:0:0
>> #37 0x0000558537237057 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x5e63057)
>> #38 0x00005585386c199a clang::ParseAST(clang::Sema&, bool, bool) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x72ed99a)
>> #39 0x00005585376ca08d clang::FrontendAction::Execute() (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x62f608d)
>> #40 0x000055853762e7ad clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x625a7ad)
>> #41 0x00005585377a673c clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x63d273c)
>> #42 0x0000558534a3220a cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x365e20a)
>> #43 0x0000558534a2e85d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
>> #44 0x0000558537454199 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::$_0>(long) Job.cpp:0:0
>> #45 0x00005585369510e6 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x557d0e6)
>> #46 0x0000558537453833 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x607f833)
>> #47 0x000055853740b427 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x6037427)
>> #48 0x000055853740b987 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x6037987)
>> #49 0x000055853742e0e9 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x605a0e9)
>> #50 0x0000558534a2dcfd clang_main(int, char**, llvm::ToolContext const&) (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x3659cfd)
>> #51 0x0000558534a3f806 main (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x366b806)
>> #52 0x00007f3d209a6c88 (/usr/lib/libc.so.6+0x25c88)
>> #53 0x00007f3d209a6d4c __libc_start_main (/usr/lib/libc.so.6+0x25d4c)
>> #54 0x0000558534a2c125 _start (/home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin/clang-19+0x3658125)
>> clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
>> ClangBuiltLinux clang version 19.0.0git (https://github.com/llvm/llvm-project.git 1f6f97e2b64a9c4c51712d32b53e07d2a20e0cc0)
>> Target: x86_64-pc-linux-gnu
>> Thread model: posix
>> InstalledDir: /home/nathan/tmp/cvise.YrEYUS5WBZ/install/llvm-bad/bin
>> Build config: +assertions
>> clang: note: diagnostic msg: Error generating preprocessed source(s) - no preprocessable inputs.
>>
>> —
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https://github.com/llvm/llvm-project/pull/99574