Regression: FE crashes in clang::TypeVisitor::Visit()

[xingxue-ibm]

Bugzilla Link	45102
Resolution	FIXED
Resolved on	Mar 09, 2020 05:42
Version	10.0
OS	Linux
Blocks	#43900
Attachments	diagnostic msg: t-797489.sh, diagnostic msg: t-797489.cpp
CC	@DougGregor,@zmodem,@zygoloid,@saarraz,@xingxue-ibm
Fixed by commit(s)	865456d

Extended Description

The front-end crashes in clang::TypeVisitor::Visit() when compiling the following small test case with CLANG 10.0.0 RC2 and the trunk. CLANG 9.0.0 and CLANG 9.0.1 compile it successfully so it is a regression.

The crash occurs with 9dcfc7c (the first buildable state after the culprit commit) and passes with a revert of 84959ae (which landed while the build was broken).

Test case:
$ cat t.cpp
template using Id = T;

template
void g() {
extern Id<void (T)> f;
f(0);
}

int main(void) { g(); }
$

Compiling with 9.0.1 passes:
$ /home/xingxue/install-9.0.1/bin/clang++ -std=c++11 -x c++ -c t.cpp
$

Compiling with 10.0.0.rc2 crashes:
$ /home/xingxue/install-10.0.0.rc2/bin/clang++ -std=c++11 -x c++ -c t.cpp
Stack dump:
0. Program arguments: /home/xingxue/install-10.0.0.rc2/bin/clang++ -std=c++11 -x c++ -c t.cpp

1.  <eof> parser at end of file
   

2.  t.cpp:4:6: instantiating function definition 'g<int>'
   

#​0 0x0000000012083c14 PrintStackTraceSignalHandler(void*) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x12083c14)
#​1 0x0000000012080e98 llvm::sys::RunSignalHandlers() (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x12080e98)
#​2 0x00000000120824f0 llvm::sys::CleanupOnSignal(unsigned long) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x120824f0)
#​3 0x0000000011ff8618 CrashRecoverySignalHandler(int) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x11ff8618)
#​4 0x00007197e59b04d8 (linux-vdso64.so.1+0x4d8)
#​5 0x0000000013e9d3d0 clang::TypeVisitor<(anonymous namespace)::GetContainedInventedTypeParmVisitor, clang::TemplateTypeParmDecl*>::Visit(clang::Type const*) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13e9d3d0)
#​6 0x0000000013e929bc clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformFunctionTypeParams(clang::SourceLocation, llvm::ArrayRefclang::ParmVarDecl*, clang::QualType const*, clang::FunctionType::ExtParameterInfo const*, llvm::SmallVectorImplclang::QualType&, llvm::SmallVectorImplclang::ParmVarDecl*, clang::Sema::ExtParameterInfoBuilder&) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13e929bc)
#​7 0x0000000013e92600 clang::Sema::SubstParmTypes(clang::SourceLocation, llvm::ArrayRefclang::ParmVarDecl*, clang::FunctionType::ExtParameterInfo const, clang::MultiLevelTemplateArgumentList const&, llvm::SmallVectorImplclang::QualType&, llvm::SmallVectorImplclang::ParmVarDecl*, clang::Sema::ExtParameterInfoBuilder&) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13e92600)
#​8 0x0000000013ece29c clang::TemplateDeclInstantiator::SubstFunctionType(clang::FunctionDecl, llvm::SmallVectorImplclang::ParmVarDecl*&) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13ece29c)
#​9 0x0000000013ecc2c4 clang::TemplateDeclInstantiator::VisitFunctionDecl(clang::FunctionDecl*, clang::TemplateParameterList*, clang::TemplateDeclInstantiator::RewriteKind) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13ecc2c4)
#​10 0x0000000013ed3840 clang::TemplateDeclInstantiator::VisitFunctionDecl(clang::FunctionDecl*) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13ed3840)
#​11 0x0000000013e94fb8 clang::declvisitor::Base<std::add_pointer, clang::TemplateDeclInstantiator, clang::Decl*>::Visit(clang::Decl*) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13e94fb8)
#​12 0x0000000013eda88c void llvm::function_ref<void ()>::callback_fn<clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&)::$_0>(long) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13eda88c)
#​13 0x00000000138200e8 clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x138200e8)
#​14 0x0000000013ed4898 clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13ed4898)
#​15 0x0000000013eb6208 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformDeclStmt(clang::DeclStmt*) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13eb6208)
#​16 0x0000000013eb0f30 clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt(clang::CompoundStmt*, bool) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13eb0f30)
#​17 0x0000000013e97720 clang::Sema::SubstStmt(clang::Stmt*, clang::MultiLevelTemplateArgumentList const&) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13e97720)
#​18 0x0000000013ed69c0 clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation, clang::FunctionDecl*, bool, bool, bool) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13ed69c0)
#​19 0x0000000013ed8ecc clang::Sema::PerformPendingInstantiations(bool) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x13ed8ecc)
#​20 0x000000001382298c clang::Sema::ActOnEndOfTranslationUnitFragment(clang::Sema::TUFragmentKind) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x1382298c)
#​21 0x000000001382311c clang::Sema::ActOnEndOfTranslationUnit() (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x1382311c)
#​22 0x000000001372c2c0 clang::Parser::ParseTopLevelDecl(clang::OpaquePtrclang::DeclGroupRef&, bool) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x1372c2c0)
#​23 0x00000000137268a0 clang::ParseAST(clang::Sema&, bool, bool) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x137268a0)
#​24 0x0000000012808c1c clang::ASTFrontendAction::ExecuteAction() (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x12808c1c)
#​25 0x0000000012e0527c clang::CodeGenAction::ExecuteAction() (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x12e0527c)
#​26 0x00000000128083f4 clang::FrontendAction::Execute() (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x128083f4)
#​27 0x00000000127a8a6c clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x127a8a6c)
#​28 0x00000000128c969c clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x128c969c)
#​29 0x00000000104d0870 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x104d0870)
#​30 0x00000000104cdf20 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x104cdf20)
#​31 0x000000001267cb94 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optionalllvm::StringRef >, std::string*, bool*) const::$_1>(long) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x1267cb94)
#​32 0x0000000011ff82a4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x11ff82a4)
#​33 0x000000001267bc98 clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optionalllvm::StringRef >, std::string*, bool*) const (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x1267bc98)
#​34 0x000000001264d834 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&) const (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x1264d834)
#​35 0x000000001264dd68 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) const (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x1264dd68)
#​36 0x0000000012662dd0 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*> >&) (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x12662dd0)
#​37 0x00000000104cd1ec main (/home/xingxue/install-10.0.0.rc2/bin/clang+++0x104cd1ec)
#​38 0x00007197e526441c generic_start_main /build/glibc-uvws04/glibc-2.27/csu/../csu/libc-start.c:310:0
#​39 0x00007197e5264618 __libc_start_main /build/glibc-uvws04/glibc-2.27/csu/../sysdeps/unix/sysv/linux/powerpc/libc-start.c:116:0
clang-10: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 10.0.0
Target: powerpc64le-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/xingxue/install-10.0.0.rc2/bin
clang-10: note: diagnostic msg: PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
clang-10: note: diagnostic msg:

---

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-10: note: diagnostic msg: /tmp/t-797489.cpp
clang-10: note: diagnostic msg: /tmp/t-797489.sh
clang-10: note: diagnostic msg:

---

$

[xingxue-ibm]

CLANG 10.0.0 RC3 fails the same way.

[zmodem]

I haven't been able to reproduce this yet. Maybe because you target ppc and I'm on X86.

Can you share the full cc1 invocation, i.e. the output of

/home/xingxue/install-10.0.0.rc2/bin/clang++ -std=c++11 -x c++ -c t.cpp -###

[xingxue-ibm]

Hi Hans, Thanks for looking at it. The output with -### is as follows.

xingxue@recycler:/bug45102$ /home/xingxue/install-10.0.0.rc3/bin/clang++ -std=c++11 -x c++ -c t.cpp -###
clang version 10.0.0
Target: powerpc64le-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/xingxue/install-10.0.0.rc3/bin
(in-process)
"/home/xingxue/temp/clang+llvm-10.0.0-rc3-powerpc64le-linux-rhel-7.4/bin/clang-10" "-cc1" "-triple" "powerpc64le-unknown-linux-gnu" "-emit-obj" "-mrelax-all" "-disable-free" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "t.cpp" "-mrelocation-model" "static" "-mthread-model" "posix" "-mframe-pointer=all" "-fmath-errno" "-fno-rounding-math" "-masm-verbose" "-mconstructor-aliases" "-target-cpu" "ppc64le" "-mfloat-abi" "hard" "-target-abi" "elfv2" "-dwarf-column-info" "-fno-split-dwarf-inlining" "-debugger-tuning=gdb" "-resource-dir" "/home/xingxue/temp/clang+llvm-10.0.0-rc3-powerpc64le-linux-rhel-7.4/lib/clang/10.0.0" "-internal-isystem" "/usr/lib/gcc/powerpc64le-linux-gnu/7.3.0/../../../../include/c++/7.3.0" "-internal-isystem" "/usr/lib/gcc/powerpc64le-linux-gnu/7.3.0/../../../../include/powerpc64le-linux-gnu/c++/7.3.0" "-internal-isystem" "/usr/lib/gcc/powerpc64le-linux-gnu/7.3.0/../../../../include/powerpc64le-linux-gnu/c++/7.3.0" "-internal-isystem" "/usr/lib/gcc/powerpc64le-linux-gnu/7.3.0/../../../../include/c++/7.3.0/backward" "-internal-isystem" "/home/xingxue/temp/clang+llvm-10.0.0-rc3-powerpc64le-linux-rhel-7.4/lib/clang/10.0.0/include/ppc_wrappers" "-internal-isystem" "/usr/local/include" "-internal-isystem" "/home/xingxue/temp/clang+llvm-10.0.0-rc3-powerpc64le-linux-rhel-7.4/lib/clang/10.0.0/include" "-internal-externc-isystem" "/usr/include/powerpc64le-linux-gnu" "-internal-externc-isystem" "/include" "-internal-externc-isystem" "/usr/include" "-std=c++11" "-fdeprecated-macro" "-fdebug-compilation-dir" "/home/xingxue/bug45102" "-ferror-limit" "19" "-fmessage-length" "0" "-fno-signed-char" "-fgnuc-version=4.2.1" "-fobjc-runtime=gcc" "-fcxx-exceptions" "-fexceptions" "-fdiagnostics-show-option" "-fcolor-diagnostics" "-faddrsig" "-o" "t.o" "-x" "c++" "t.cpp"
xingxue@recycler:/bug45102$

[zmodem]

Thank you. I tried your cc1 invocation, but it still doesn't crash for me.

Can you try running the cc1 invocation under gdb or another debugger and try to see why it crashes?

[xingxue-ibm]

GDB shows the following seg-fault.

Program received signal SIGSEGV, Segmentation fault.
clang::Decl::isImplicit (this=0x0) at /home/xingxue/llvm/rc3/llvm-project/clang/include/clang/AST/DeclBase.h:558
558 bool isImplicit() const { return Implicit; }
(gdb) where
#​0 clang::Decl::isImplicit (this=0x0) at /home/xingxue/llvm/rc3/llvm-project/clang/include/clang/AST/DeclBase.h:558
#​1 0x0000000018de9490 in (anonymous namespace)::GetContainedInventedTypeParmVisitor::VisitTemplateTypeParmType (this=0x7fffffff6a80, T=0x1d0cff00)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2165
#​2 0x0000000018de83c4 in clang::TypeVisitor<(anonymous namespace)::GetContainedInventedTypeParmVisitor, clang::TemplateTypeParmDecl*>::Visit (this=0x7fffffff6a80,
T=0x1d0cff00) at tools/clang/include/clang/AST/TypeNodes.inc:66
#​3 0x0000000018ddbdbc in (anonymous namespace)::GetContainedInventedTypeParmVisitor::Visit (this=0x7fffffff6a80, T=...)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2160
#​4 0x0000000018ddb660 in clang::Sema::SubstParmVarDecl (this=0x1d0e8380, OldParm=0x1d11fdc8, TemplateArgs=..., indexAdjustment=0, NumExpansions=...,
ExpectParameterPack=false) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2291
#​5 0x0000000018e1b3b0 in (anonymous namespace)::TemplateInstantiator::TransformFunctionTypeParam (this=0x7fffffff7208, OldParm=0x1d11fdc8, indexAdjustment=0,
NumExpansions=..., ExpectParameterPack=false) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:1700
#​6 0x0000000018ddcbe0 in clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformFunctionTypeParams (this=0x7fffffff7208, Loc=..., Params=...,
ParamTypes=0x0, ParamInfos=0x0, OutParamTypes=..., PVars=0x7fffffff7f10, PInfos=...) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/TreeTransform.h:5328
#​7 0x0000000018ddc3ec in clang::Sema::SubstParmTypes (this=0x1d0e8380, Loc=..., Params=..., ExtParamInfos=0x0, TemplateArgs=..., ParamTypes=...,
OutParams=0x7fffffff7f10, ParamInfos=...) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:2399
#​8 0x0000000018e4f500 in clang::TemplateDeclInstantiator::SubstFunctionType (this=0x7fffffff8488, D=0x1d11fd18, Params=...)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:4158
#​9 0x0000000018e4d114 in clang::TemplateDeclInstantiator::VisitFunctionDecl (this=0x7fffffff8488, D=0x1d11fd18, TemplateParams=0x0,
FunctionRewriteKind=clang::TemplateDeclInstantiator::RewriteKind::None) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:1835
#​10 0x0000000018e54f2c in clang::TemplateDeclInstantiator::VisitFunctionDecl (this=0x7fffffff8488, D=0x1d11fd18)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:3402
#​11 0x0000000018e32d04 in clang::declvisitor::Base<std::add_pointer, clang::TemplateDeclInstantiator, clang::Decl*>::Visit (this=0x7fffffff8488, D=0x1d11fd18)
at tools/clang/include/clang/AST/DeclNodes.inc:401
#​12 0x0000000018e5b990 in clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&)::$0::operator()() const (
this=0x7fffffff8448) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:3678
#​13 0x0000000018e5b928 in llvm::function_ref<void ()>::callback_fn<clang::Sema::SubstDecl(clang::Decl*, clang::DeclContext*, clang::MultiLevelTemplateArgumentList const&)::$0>(long) (callable=140737488323656) at /home/xingxue/llvm/rc3/llvm-project/llvm/include/llvm/ADT/STLExtras.h:108
#​14 0x0000000014543320 in llvm::function_ref<void ()>::operator()() const (this=0x7fffffff8328)
at /home/xingxue/llvm/rc3/llvm-project/llvm/include/llvm/ADT/STLExtras.h:125
#​15 0x0000000017f7df64 in clang::runWithSufficientStackSpace(llvm::function_ref<void ()>, llvm::function_ref<void ()>) (Diag=..., Fn=...)
at /home/xingxue/llvm/rc3/llvm-project/clang/include/clang/Basic/Stack.h:46
#​16 0x0000000017f6ec40 in clang::Sema::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (this=0x1d0e8380, Loc=..., Fn=...)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/Sema.cpp:425
#​17 0x0000000018e56410 in clang::Sema::SubstDecl (this=0x1d0e8380, D=0x1d11fd18, Owner=0x1d120220, TemplateArgs=...)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:3677
#​18 0x0000000018e25ea4 in (anonymous namespace)::TemplateInstantiator::TransformDefinition (this=0x7fffffff9708, Loc=..., D=0x1d11fd18)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:1225
#​19 0x0000000018e1e05c in clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformDeclStmt (this=0x7fffffff9708, S=0x1d11fe38)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/TreeTransform.h:7168
#​20 0x0000000018de1244 in clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt (this=0x7fffffff9708, S=0x1d11fe38,
SDK=clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::SDK_Discarded) at tools/clang/include/clang/AST/StmtNodes.inc:97
#​21 0x0000000018e0d05c in clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt (this=0x7fffffff9708, S=0x1d11feb8,
IsStmtExpr=false) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/TreeTransform.h:6779
#​22 0x0000000018e1d28c in clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformCompoundStmt (this=0x7fffffff9708, S=0x1d11feb8)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/TreeTransform.h:6765
---Type to continue, or q to quit---
#​23 0x0000000018de1144 in clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::TransformStmt (this=0x7fffffff9708, S=0x1d11feb8,
SDK=clang::TreeTransform<(anonymous namespace)::TemplateInstantiator>::SDK_Discarded) at tools/clang/include/clang/AST/StmtNodes.inc:73
#​24 0x0000000018de0e80 in clang::Sema::SubstStmt (this=0x1d0e8380, S=0x1d11feb8, TemplateArgs=...)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.cpp:3373
#​25 0x0000000018e581a4 in clang::Sema::InstantiateFunctionDefinition (this=0x1d0e8380, PointOfInstantiation=..., Function=0x1d1201d8, Recursive=true,
DefinitionRequired=false, AtEndOfTU=true) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:4709
#​26 0x0000000018e5aa6c in clang::Sema::PerformPendingInstantiations (this=0x1d0e8380, LocalOnly=false)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:5952
#​27 0x0000000017f70570 in clang::Sema::ActOnEndOfTranslationUnitFragment (this=0x1d0e8380, Kind=clang::Sema::Normal)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/Sema.cpp:951
#​28 0x0000000017f70858 in clang::Sema::ActOnEndOfTranslationUnit (this=0x1d0e8380) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/Sema.cpp:989
#​29 0x0000000017e0fcc0 in clang::Parser::ParseTopLevelDecl (this=0x1d0f1570, Result=..., IsFirstDecl=false)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Parse/Parser.cpp:660
#​30 0x0000000017e0a380 in clang::ParseAST (S=..., PrintStats=false, SkipFunctionBodies=false) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Parse/ParseAST.cpp:158
#​31 0x000000001559b968 in clang::ASTFrontendAction::ExecuteAction (this=0x1d0ae270) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1043
#​32 0x00000000161ad628 in clang::CodeGenAction::ExecuteAction (this=0x1d0ae270) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:1179
#​33 0x000000001559b1d8 in clang::FrontendAction::Execute (this=0x1d0ae270) at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Frontend/FrontendAction.cpp:936
#​34 0x0000000015507210 in clang::CompilerInstance::ExecuteAction (this=0x1d081820, Act=...)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:965
#​35 0x000000001578d160 in clang::ExecuteCompilerInvocation (Clang=0x1d081820)
at /home/xingxue/llvm/rc3/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:290
#​36 0x0000000010dfea80 in cc1_main (Argv=..., Argv0=0x7fffffffeec6 "/home/xingxue/llvm/rc3/build/bin/clang-10",
MainAddr=0x10deb510 <GetExecutablePath[abi:cxx11](char const*, bool)>) at /home/xingxue/llvm/rc3/llvm-project/clang/tools/driver/cc1_main.cpp:240
#​37 0x0000000010dec864 in ExecuteCC1Tool (ArgV=...) at /home/xingxue/llvm/rc3/llvm-project/clang/tools/driver/driver.cpp:328
#​38 0x0000000010debba0 in main (argc=70, argv=0x7fffffffe948) at /home/xingxue/llvm/rc3/llvm-project/clang/tools/driver/driver.cpp:402
(gdb)

[zmodem]

#​0 clang::Decl::isImplicit (this=0x0) at
/home/xingxue/llvm/rc3/llvm-project/clang/include/clang/AST/DeclBase.h:558
#​1 0x0000000018de9490 in (anonymous
namespace)::GetContainedInventedTypeParmVisitor::VisitTemplateTypeParmType
(this=0x7fffffff6a80, T=0x1d0cff00)
at
/home/xingxue/llvm/rc3/llvm-project/clang/lib/Sema/SemaTemplateInstantiate.
cpp:2165

Looks like in GetContainedInventedTypeParmVisitor::VisitTemplateTypeParmType(), T->getDecl() is returning NULL and that's getting fed into Decl::isImplicit().

Saar, do you have any idea how that could happen?

[saarraz]

I will take a look shortly

[saarraz]

Fixed now on trunk and release, thanks for reporting!

[zmodem]

Fixed now on trunk and release, thanks for reporting!

Thanks!

For my notes, the fix is in master 865456d / 10.x 7c18c2f.