[lldb-dev] [cfe-dev] stable layout bug for imported record decls.
Gábor Márton via lldb-dev
lldb-dev at lists.llvm.org
Wed Aug 15 08:43:31 PDT 2018
Just sending again the trace, because gmail broke the lines pretty badly.
(1)
=== "To" ASTContext A, "From" ASTContext X, MINIMAL import through
ExternalASTSource inteface
clang::ASTImporter::Import (this=0x13b3c50, FromT=...) at
../../git/llvm/tools/clang/lib/AST/ASTImporter.cpp:6983
lldb_private::ClangASTImporter::CopyType (this=0x12a3480,
dst_ast=0x1363420, src_ast=0x11f7980, type=...) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:61
lldb_private::ClangASTSource::GuardedCopyType (this=0x12394b0,
src_type=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:2038
lldb_private::ClangExpressionDeclMap::GetVariableValue (this=0x12394b0,
var=warning: RTTI symbol not found for class
'std::_Sp_counted_ptr<lldb_private::Variable*, (__gnu_cxx::_Lock_policy)2>'
lldb_private::ClangExpressionDeclMap::AddOneVariable (this=0x12394b0,
context=..., var=warning: RTTI symbol not found for class
'std::_Sp_counted_ptr<lldb_private::Variable*, (__gnu_cxx::_Lock_policy)2>'
lldb_private::ClangExpressionDeclMap::FindExternalVisibleDecls
(this=0x12394b0, context=..., module_sp=std::shared_ptr (empty) 0x0,
namespace_decl=..., current_id=3) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:1235
lldb_private::ClangExpressionDeclMap::FindExternalVisibleDecls
(this=0x12394b0, context=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:842
lldb_private::ClangASTSource::FindExternalVisibleDeclsByName
(this=0x12394b0, decl_ctx=0x1371298, clang_decl_name=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:261
lldb_private::ClangASTSource::ClangASTSourceProxy::FindExternalVisibleDeclsByName
(this=0x105e230, DC=0x1371298, Name=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h:244
clang::DeclContext::lookup (this=0x1371298, Name=...) at
../../git/llvm/tools/clang/lib/AST/DeclBase.cpp:1599
LookupDirect (S=..., R=..., DC=0x1371298) at
../../git/llvm/tools/clang/lib/Sema/SemaLookup.cpp:84
CppNamespaceLookup (S=..., R=..., Context=..., NS=0x1d69dd8, UDirs=...) at
../../git/llvm/tools/clang/lib/Sema/SemaLookup.cpp:942
clang::Sema::CppLookupName (this=0x1d74cd0, R=..., S=0x1d80510) at
../../git/llvm/tools/clang/lib/Sema/SemaLookup.cpp:1322
...
clang::Sema::ActOnUsingDeclaration (this=0x1d74cd0, S=0x1d93820,
AS=clang::AS_none, UsingLoc=..., TypenameLoc=..., SS=..., Name=...,
EllipsisLoc=..., AttrList=...) at
../../git/llvm/tools/clang/lib/Sema/SemaDeclCXX.cpp:9418
clang::Parser::ParseUsingDeclaration (this=0x1d7bd90,
Context=clang::DeclaratorContext::BlockContext, TemplateInfo=...,
UsingLoc=..., DeclEnd=..., AS=clang::AS_none) at
../../git/llvm/tools/clang/lib/Parse/ParseDeclCXX.cpp:710
...
clang::Parser::ParseTopLevelDecl (this=0x1d7bd90, Result=...) at
../../git/llvm/tools/clang/lib/Parse/Parser.cpp:610
clang::ParseAST (S=..., PrintStats=false, SkipFunctionBodies=false) at
../../git/llvm/tools/clang/lib/Parse/ParseAST.cpp:158
clang::ParseAST (PP=..., Consumer=0x1a2dfc0, Ctx=..., PrintStats=false,
TUKind=clang::TU_Complete, CompletionConsumer=0x0,
SkipFunctionBodies=false) at
../../git/llvm/tools/clang/lib/Parse/ParseAST.cpp:111
lldb_private::ClangExpressionParser::Parse (this=0x7fff14cdfe90,
diagnostic_manager=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp:608
lldb_private::ClangUserExpression::Parse (this=0x1d1d530,
diagnostic_manager=..., exe_ctx=...,
execution_policy=lldb_private::eExecutionPolicyOnlyWhenNeeded,
keep_result_in_memory=true, generate_debug_info=false) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp:495
lldb_private::UserExpression::Evaluate (exe_ctx=..., options=...,
expr="tpi", prefix="", result_valobj_sp=..., error=..., line_offset=0,
fixed_expression=0x1a95738, jit_module_sp_ptr=0x0) at
../../git/llvm/tools/lldb/source/Expression/UserExpression.cpp:237
lldb_private::Target::EvaluateExpression (this=0x1b32570, expr="tpi",
exe_scope=0x7fe73ca42d90, result_valobj_sp=..., options=...,
fixed_expression=0x1a95738) at
../../git/llvm/tools/lldb/source/Target/Target.cpp:2308
lldb_private::CommandObjectExpression::EvaluateExpression (this=0x1a953b0,
expr=0x7fff14ce0d58 "tpi", output_stream=0x7fff14ce16e8,
error_stream=0x7fff14ce1740, result=0x7fff14ce16e8) at
../../git/llvm/tools/lldb/source/Commands/CommandObjectExpression.cpp:377
(2)
=== ASTContext A, "From" ASTContext X, MINIMAL import through
ExternalASTSource inteface
clang::ASTImporter::Import (this=0x13b3c50, FromD=0x13bba18) at
../../git/llvm/tools/clang/lib/AST/ASTImporter.cpp:7040
lldb_private::ClangASTImporter::CopyDecl (this=0x12a3480,
dst_ast=0x1363420, src_ast=0x11f7980, decl=0x13bba18) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:102
lldb_private::ClangASTSource::CopyDecl (this=0x12394b0, src_decl=0x13bba18)
at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:1991
lldb_private::ClangASTSource::FindExternalLexicalDecls(clang::DeclContext
const*, llvm::function_ref<bool (clang::Decl::Kind)>,
llvm::SmallVectorImpl<clang::Decl*>&) (this=0x12394b0,
decl_context=0x13b2048, predicate=..., decls=llvm::SmallVector of Size 0,
Capacity 64) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:635
lldb_private::ClangASTSource::ClangASTSourceProxy::FindExternalLexicalDecls(clang::DeclContext
const*, llvm::function_ref<bool (clang::Decl::Kind)>,
llvm::SmallVectorImpl<clang::Decl*>&) (this=0x105e230, DC=0x13b2048,
IsKindWeWant=..., Decls=llvm::SmallVector of Size 0, Capacity 64) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h:251
clang::RecordDecl::LoadFieldsFromExternalStorage (this=0x13b2010) at
../../git/llvm/tools/clang/lib/AST/Decl.cpp:4137
clang::RecordDecl::field_begin (this=0x13b2010) at
../../git/llvm/tools/clang/lib/AST/Decl.cpp:4109
clang::RecordDecl::fields (this=0x13b2010) at
../../git/llvm/tools/clang/include/clang/AST/Decl.h:3751
(anonymous namespace)::EmptySubobjectMap::ComputeEmptySubobjectSizes
(this=0x7fffd5c774d0) at
../../git/llvm/tools/clang/lib/AST/RecordLayoutBuilder.cpp:206
...
clang::CodeGen::CodeGenTypes::ComputeRecordLayout (this=0x1d6e2d8,
D=0x1daab50, Ty=0x1d70550) at
../../git/llvm/tools/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp:725
...
clang::CodeGen::CodeGenModule::EmitTopLevelDecl (this=0x1d6e200,
D=0x1daaa00) at
../../git/llvm/tools/clang/lib/CodeGen/CodeGenModule.cpp:4571
(anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl
(this=0x1d6c620, DG=...) at
../../git/llvm/tools/clang/lib/CodeGen/ModuleBuilder.cpp:160
lldb_private::ASTResultSynthesizer::HandleTopLevelDecl (this=0x1a2dfc0,
D=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.cpp:109
clang::ParseAST (S=..., PrintStats=false, SkipFunctionBodies=false) at
../../git/llvm/tools/clang/lib/Parse/ParseAST.cpp:162
clang::ParseAST (PP=..., Consumer=0x1a2dfc0, Ctx=..., PrintStats=false,
TUKind=clang::TU_Complete, CompletionConsumer=0x0,
SkipFunctionBodies=false) at
../../git/llvm/tools/clang/lib/Parse/ParseAST.cpp:111
lldb_private::ClangExpressionParser::Parse (this=0x7fff14cdfe90,
diagnostic_manager=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp:608
lldb_private::ClangUserExpression::Parse (this=0x1d1d530,
diagnostic_manager=..., exe_ctx=...,
execution_policy=lldb_private::eExecutionPolicyOnlyWhenNeeded,
keep_result_in_memory=true, generate_debug_info=false) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp:495
lldb_private::UserExpression::Evaluate (exe_ctx=..., options=...,
expr="tpi", prefix="", result_valobj_sp=..., error=..., line_offset=0,
fixed_expression=0x1a95738, jit_module_sp_ptr=0x0) at
../../git/llvm/tools/lldb/source/Expression/UserExpression.cpp:237
lldb_private::Target::EvaluateExpression (this=0x1b32570, expr="tpi",
exe_scope=0x7fe73ca42d90, result_valobj_sp=..., options=...,
fixed_expression=0x1a95738) at
../../git/llvm/tools/lldb/source/Target/Target.cpp:2308
lldb_private::CommandObjectExpression::EvaluateExpression (this=0x1a953b0,
expr=0x7fff14ce0d58 "tpi", output_stream=0x7fff14ce16e8,
error_stream=0x7fff14ce1740, result=0x7fff14ce16e8) at
../../git/llvm/tools/lldb/source/Commands/CommandObjectExpression.cpp:377
(3)
=== ASTContext B, "From" ASTContext Z, ASTImporter is in MINIMAL mode, but
ImportDefinition forces a full import
clang::ASTImporter::ImportDefinition (this=0x1d75200, From=0x1c01048) at
../../git/llvm/tools/clang/lib/AST/ASTImporter.cpp:7519
lldb_private::ClangASTImporter::Minion::ImportDefinitionTo (this=0x1d75200,
to=0x1d1b8d8, from=0x1c01048) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:889
lldb_private::ClangASTImporter::CompleteTagDecl (this=0x1c96360,
decl=0x1d1b8d8) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:560
lldb_private::ClangASTSource::CompleteType (this=0x1a66560,
tag_decl=0x1d1b8d8) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:299
lldb_private::ClangASTSource::ClangASTSourceProxy::CompleteType
(this=0x1a24d60, Tag=0x1d1b8d8) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h:255
GetCompleteQualType (ast=0x1cde470, qual_type=..., allow_completion=true)
at ../../git/llvm/tools/lldb/source/Symbol/ClangASTContext.cpp:2515
lldb_private::ClangASTContext::GetNumChildren (this=0x1c456f0,
type=0x1d1b980, omit_empty_base_classes=true) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTContext.cpp:5341
lldb_private::CompilerType::GetNumChildren (this=0x7fff14cdfe18,
omit_empty_base_classes=true) at
../../git/llvm/tools/lldb/source/Symbol/CompilerType.cpp:541
lldb_private::ClangASTContext::GetNumChildren (this=0x1c456f0,
type=0x1d1ba10, omit_empty_base_classes=true) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTContext.cpp:5443
lldb_private::CompilerType::GetNumChildren (this=0x7fff14ce0018,
omit_empty_base_classes=true) at
../../git/llvm/tools/lldb/source/Symbol/CompilerType.cpp:541
lldb_private::ClangASTContext::GetNumChildren (this=0x1c456f0,
type=0x1d1baa0, omit_empty_base_classes=true) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTContext.cpp:5472
lldb_private::CompilerType::GetNumChildren (this=0x7fff14ce01d0,
omit_empty_base_classes=true) at
../../git/llvm/tools/lldb/source/Symbol/CompilerType.cpp:541
lldb_private::ValueObjectConstResult::CalculateNumChildren (this=0x1d6c620,
max=4294967295) at
../../git/llvm/tools/lldb/source/Core/ValueObjectConstResult.cpp:211
lldb_private::ValueObject::GetNumChildren (this=0x1d6c620, max=4294967295)
at ../../git/llvm/tools/lldb/source/Core/ValueObject.cpp:601
lldb_private::FormatManager::ShouldPrintAsOneLiner (this=0x7fe7676031d8
<GetFormatManager()::g_format_manager>, valobj=...) at
../../git/llvm/tools/lldb/source/DataFormatters/FormatManager.cpp:494
lldb_private::DataVisualization::ShouldPrintAsOneLiner (valobj=...) at
../../git/llvm/tools/lldb/source/DataFormatters/DataVisualization.cpp:33
lldb_private::ValueObjectPrinter::PrintChildrenIfNeeded
(this=0x7fff14ce0560, value_printed=true, summary_printed=false) at
../../git/llvm/tools/lldb/source/DataFormatters/ValueObjectPrinter.cpp:771
lldb_private::ValueObjectPrinter::PrintValueObject
...
lldb_private::ValueObject::Dump (this=0x1d6c620, s=..., options=...) at
../../git/llvm/tools/lldb/source/Core/ValueObject.cpp:2742
lldb_private::CommandObjectExpression::EvaluateExpression
(4)
==== ASTContext B, "From" ASTContext Y, MINIMAL import, skips
ExternalASTSource interface
clang::ASTImporter::Import (this=0x1d74cd0, FromT=...) at
../../git/llvm/tools/clang/lib/AST/ASTImporter.cpp:6983
lldb_private::ClangASTImporter::CopyType (this=0x1c96360,
dst_ast=0x1cde470, src_ast=0x1d5bf60, type=...) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:61
lldb_private::ClangASTImporter::CopyType (this=0x1c96360,
dst_ast=0x1cde470, src_ast=0x1d5bf60, type=0x1daad10) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:70
lldb_private::ClangASTImporter::DeportType (this=0x1c96360,
dst_ctx=0x1cde470, src_ctx=0x1d5bf60, type=0x1daad10) at
../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:268
lldb_private::ClangExpressionDeclMap::DeportType (this=0x1c98e00,
target=..., source=..., parser_type=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:288
lldb_private::ClangExpressionDeclMap::AddPersistentVariable
(this=0x1c98e00, decl=0x1daaff8, name=..., parser_type=..., is_result=true,
is_lvalue=true) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:332
IRForTarget::CreateResultVariable (this=0x7fff14cdf8c0, llvm_function=...)
at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp:407
IRForTarget::runOnModule (this=0x7fff14cdf8c0, llvm_module=...) at
../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp:2102
lldb_private::ClangExpressionParser::PrepareForExecution
...
lldb_private::CommandObjectExpression::EvaluateExpression (this=0x1a953b0,
expr=0x7fff14ce0d58 "tpi", output_stream=0x7fff14ce16e8,
error_stream=0x7fff14ce1740, result=0x7fff14ce16e8) at
../../git/llvm/tools/lldb/source/Commands/CommandObjectExpression.cpp:377
On Wed, Aug 15, 2018 at 5:36 PM Gábor Márton <martongabesz at gmail.com> wrote:
> Lang,
>
> I've done some more research on this and here is what I've found so far.
>
> LLDB uses the ExternalASTSource interface and it provides its own
> implementation for it (lldb_private::ClangASTSource).
> ClangASTSource is being used in at least 3 modes (all of these uses
> the ASTImporter):
> (1) to do a minimal import for a Type/Decl, this is used for lookup
> (2) to do a minimal import for a Type/Decl, this is used for computing
> the record layout
> (3) to complete the Type which has been imported in a minimal mode
> previously. The completion is done via ASTImporter::ImportDefinition,
> which does a full import of a TagDecl even in minimal mode.
>
> Besides, there is a fourth method which exercises the ASTImporter, but
> it does not use the ExternalASTSource interface (4). [[ Actually, (4)
> happens before than (3) in program runtime. ]]
>
> So, it is kind of weird to me, that we use a simple minimal import in
> (2) for computing the record layout, perhaps we could make a change in
> LLDB to call `lldb_private::ClangASTSource::CompleteType` to achieve a
> full import in this case? Instead of changing the logic in
> clang::ASTImporter? By doing so, I think the logic would be aligned
> with Richard's idea.
>
> Gabor
>
> (1)
> === "To" ASTContext A, "From" ASTContext X, MINIMAL import through
> ExternalASTSource inteface
> clang::ASTImporter::Import (this=0x13b3c50, FromT=...) at
> ../../git/llvm/tools/clang/lib/AST/ASTImporter.cpp:6983
> lldb_private::ClangASTImporter::CopyType (this=0x12a3480,
> dst_ast=0x1363420, src_ast=0x11f7980, type=...) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:61
> lldb_private::ClangASTSource::GuardedCopyType (this=0x12394b0,
> src_type=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:2038
> lldb_private::ClangExpressionDeclMap::GetVariableValue
> (this=0x12394b0, var=warning: RTTI symbol not found for class
> 'std::_Sp_counted_ptr<lldb_private::Variable*,
> (__gnu_cxx::_Lock_policy)2>'
> lldb_private::ClangExpressionDeclMap::AddOneVariable (this=0x12394b0,
> context=..., var=warning: RTTI symbol not found for class
> 'std::_Sp_counted_ptr<lldb_private::Variable*,
> (__gnu_cxx::_Lock_policy)2>'
> lldb_private::ClangExpressionDeclMap::FindExternalVisibleDecls
> (this=0x12394b0, context=..., module_sp=std::shared_ptr (empty) 0x0,
> namespace_decl=..., current_id=3) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:1235
> lldb_private::ClangExpressionDeclMap::FindExternalVisibleDecls
> (this=0x12394b0, context=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:842
> lldb_private::ClangASTSource::FindExternalVisibleDeclsByName
> (this=0x12394b0, decl_ctx=0x1371298, clang_decl_name=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:261
>
> lldb_private::ClangASTSource::ClangASTSourceProxy::FindExternalVisibleDeclsByName
> (this=0x105e230, DC=0x1371298, Name=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h:244
> clang::DeclContext::lookup (this=0x1371298, Name=...) at
> ../../git/llvm/tools/clang/lib/AST/DeclBase.cpp:1599
> LookupDirect (S=..., R=..., DC=0x1371298) at
> ../../git/llvm/tools/clang/lib/Sema/SemaLookup.cpp:84
> CppNamespaceLookup (S=..., R=..., Context=..., NS=0x1d69dd8,
> UDirs=...) at ../../git/llvm/tools/clang/lib/Sema/SemaLookup.cpp:942
> clang::Sema::CppLookupName (this=0x1d74cd0, R=..., S=0x1d80510) at
> ../../git/llvm/tools/clang/lib/Sema/SemaLookup.cpp:1322
> ...
> clang::Sema::ActOnUsingDeclaration (this=0x1d74cd0, S=0x1d93820,
> AS=clang::AS_none, UsingLoc=..., TypenameLoc=..., SS=..., Name=...,
> EllipsisLoc=..., AttrList=...) at
> ../../git/llvm/tools/clang/lib/Sema/SemaDeclCXX.cpp:9418
> clang::Parser::ParseUsingDeclaration (this=0x1d7bd90,
> Context=clang::DeclaratorContext::BlockContext, TemplateInfo=...,
> UsingLoc=..., DeclEnd=..., AS=clang::AS_none) at
> ../../git/llvm/tools/clang/lib/Parse/ParseDeclCXX.cpp:710
> ...
> clang::Parser::ParseTopLevelDecl (this=0x1d7bd90, Result=...) at
> ../../git/llvm/tools/clang/lib/Parse/Parser.cpp:610
> clang::ParseAST (S=..., PrintStats=false, SkipFunctionBodies=false) at
> ../../git/llvm/tools/clang/lib/Parse/ParseAST.cpp:158
> clang::ParseAST (PP=..., Consumer=0x1a2dfc0, Ctx=...,
> PrintStats=false, TUKind=clang::TU_Complete, CompletionConsumer=0x0,
> SkipFunctionBodies=false) at
> ../../git/llvm/tools/clang/lib/Parse/ParseAST.cpp:111
> lldb_private::ClangExpressionParser::Parse (this=0x7fff14cdfe90,
> diagnostic_manager=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp:608
> lldb_private::ClangUserExpression::Parse (this=0x1d1d530,
> diagnostic_manager=..., exe_ctx=...,
> execution_policy=lldb_private::eExecutionPolicyOnlyWhenNeeded,
> keep_result_in_memory=true, generate_debug_info=false) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp:495
> lldb_private::UserExpression::Evaluate (exe_ctx=..., options=...,
> expr="tpi", prefix="", result_valobj_sp=..., error=..., line_offset=0,
> fixed_expression=0x1a95738, jit_module_sp_ptr=0x0) at
> ../../git/llvm/tools/lldb/source/Expression/UserExpression.cpp:237
> lldb_private::Target::EvaluateExpression (this=0x1b32570, expr="tpi",
> exe_scope=0x7fe73ca42d90, result_valobj_sp=..., options=...,
> fixed_expression=0x1a95738) at
> ../../git/llvm/tools/lldb/source/Target/Target.cpp:2308
> lldb_private::CommandObjectExpression::EvaluateExpression
> (this=0x1a953b0, expr=0x7fff14ce0d58 "tpi",
> output_stream=0x7fff14ce16e8, error_stream=0x7fff14ce1740,
> result=0x7fff14ce16e8) at
> ../../git/llvm/tools/lldb/source/Commands/CommandObjectExpression.cpp:377
>
>
> (2)
> === ASTContext A, "From" ASTContext X, MINIMAL import through
> ExternalASTSource inteface
> clang::ASTImporter::Import (this=0x13b3c50, FromD=0x13bba18) at
> ../../git/llvm/tools/clang/lib/AST/ASTImporter.cpp:7040
> lldb_private::ClangASTImporter::CopyDecl (this=0x12a3480,
> dst_ast=0x1363420, src_ast=0x11f7980, decl=0x13bba18) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:102
> lldb_private::ClangASTSource::CopyDecl (this=0x12394b0,
> src_decl=0x13bba18) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:1991
> lldb_private::ClangASTSource::FindExternalLexicalDecls(clang::DeclContext
> const*, llvm::function_ref<bool (clang::Decl::Kind)>,
> llvm::SmallVectorImpl<clang::Decl*>&) (this=0x12394b0,
> decl_context=0x13b2048, predicate=..., decls=llvm::SmallVector of Size
> 0, Capacity 64) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:635
>
> lldb_private::ClangASTSource::ClangASTSourceProxy::FindExternalLexicalDecls(clang::DeclContext
> const*, llvm::function_ref<bool (clang::Decl::Kind)>,
> llvm::SmallVectorImpl<clang::Decl*>&) (this=0x105e230, DC=0x13b2048,
> IsKindWeWant=..., Decls=llvm::SmallVector of Size 0, Capacity 64) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h:251
> clang::RecordDecl::LoadFieldsFromExternalStorage (this=0x13b2010) at
> ../../git/llvm/tools/clang/lib/AST/Decl.cpp:4137
> clang::RecordDecl::field_begin (this=0x13b2010) at
> ../../git/llvm/tools/clang/lib/AST/Decl.cpp:4109
> clang::RecordDecl::fields (this=0x13b2010) at
> ../../git/llvm/tools/clang/include/clang/AST/Decl.h:3751
> (anonymous namespace)::EmptySubobjectMap::ComputeEmptySubobjectSizes
> (this=0x7fffd5c774d0) at
> ../../git/llvm/tools/clang/lib/AST/RecordLayoutBuilder.cpp:206
> ...
> clang::CodeGen::CodeGenTypes::ComputeRecordLayout (this=0x1d6e2d8,
> D=0x1daab50, Ty=0x1d70550) at
> ../../git/llvm/tools/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp:725
> ...
> clang::CodeGen::CodeGenModule::EmitTopLevelDecl (this=0x1d6e200,
> D=0x1daaa00) at
> ../../git/llvm/tools/clang/lib/CodeGen/CodeGenModule.cpp:4571
> (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl
> (this=0x1d6c620, DG=...) at
> ../../git/llvm/tools/clang/lib/CodeGen/ModuleBuilder.cpp:160
> lldb_private::ASTResultSynthesizer::HandleTopLevelDecl
> (this=0x1a2dfc0, D=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.cpp:109
> clang::ParseAST (S=..., PrintStats=false, SkipFunctionBodies=false) at
> ../../git/llvm/tools/clang/lib/Parse/ParseAST.cpp:162
> clang::ParseAST (PP=..., Consumer=0x1a2dfc0, Ctx=...,
> PrintStats=false, TUKind=clang::TU_Complete, CompletionConsumer=0x0,
> SkipFunctionBodies=false) at
> ../../git/llvm/tools/clang/lib/Parse/ParseAST.cpp:111
> lldb_private::ClangExpressionParser::Parse (this=0x7fff14cdfe90,
> diagnostic_manager=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp:608
> lldb_private::ClangUserExpression::Parse (this=0x1d1d530,
> diagnostic_manager=..., exe_ctx=...,
> execution_policy=lldb_private::eExecutionPolicyOnlyWhenNeeded,
> keep_result_in_memory=true, generate_debug_info=false) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp:495
> lldb_private::UserExpression::Evaluate (exe_ctx=..., options=...,
> expr="tpi", prefix="", result_valobj_sp=..., error=..., line_offset=0,
> fixed_expression=0x1a95738, jit_module_sp_ptr=0x0) at
> ../../git/llvm/tools/lldb/source/Expression/UserExpression.cpp:237
> lldb_private::Target::EvaluateExpression (this=0x1b32570, expr="tpi",
> exe_scope=0x7fe73ca42d90, result_valobj_sp=..., options=...,
> fixed_expression=0x1a95738) at
> ../../git/llvm/tools/lldb/source/Target/Target.cpp:2308
> lldb_private::CommandObjectExpression::EvaluateExpression
> (this=0x1a953b0, expr=0x7fff14ce0d58 "tpi",
> output_stream=0x7fff14ce16e8, error_stream=0x7fff14ce1740,
> result=0x7fff14ce16e8) at
> ../../git/llvm/tools/lldb/source/Commands/CommandObjectExpression.cpp:377
>
>
> (3)
> === ASTContext B, "From" ASTContext Z, ASTImporter is in MINIMAL mode,
> but ImportDefinition forces a full import
> clang::ASTImporter::ImportDefinition (this=0x1d75200, From=0x1c01048)
> at ../../git/llvm/tools/clang/lib/AST/ASTImporter.cpp:7519
> lldb_private::ClangASTImporter::Minion::ImportDefinitionTo
> (this=0x1d75200, to=0x1d1b8d8, from=0x1c01048) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:889
> lldb_private::ClangASTImporter::CompleteTagDecl (this=0x1c96360,
> decl=0x1d1b8d8) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:560
> lldb_private::ClangASTSource::CompleteType (this=0x1a66560,
> tag_decl=0x1d1b8d8) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:299
> lldb_private::ClangASTSource::ClangASTSourceProxy::CompleteType
> (this=0x1a24d60, Tag=0x1d1b8d8) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h:255
> GetCompleteQualType (ast=0x1cde470, qual_type=...,
> allow_completion=true) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTContext.cpp:2515
> lldb_private::ClangASTContext::GetNumChildren (this=0x1c456f0,
> type=0x1d1b980, omit_empty_base_classes=true) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTContext.cpp:5341
> lldb_private::CompilerType::GetNumChildren (this=0x7fff14cdfe18,
> omit_empty_base_classes=true) at
> ../../git/llvm/tools/lldb/source/Symbol/CompilerType.cpp:541
> lldb_private::ClangASTContext::GetNumChildren (this=0x1c456f0,
> type=0x1d1ba10, omit_empty_base_classes=true) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTContext.cpp:5443
> lldb_private::CompilerType::GetNumChildren (this=0x7fff14ce0018,
> omit_empty_base_classes=true) at
> ../../git/llvm/tools/lldb/source/Symbol/CompilerType.cpp:541
> lldb_private::ClangASTContext::GetNumChildren (this=0x1c456f0,
> type=0x1d1baa0, omit_empty_base_classes=true) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTContext.cpp:5472
> lldb_private::CompilerType::GetNumChildren (this=0x7fff14ce01d0,
> omit_empty_base_classes=true) at
> ../../git/llvm/tools/lldb/source/Symbol/CompilerType.cpp:541
> lldb_private::ValueObjectConstResult::CalculateNumChildren
> (this=0x1d6c620, max=4294967295) at
> ../../git/llvm/tools/lldb/source/Core/ValueObjectConstResult.cpp:211
> lldb_private::ValueObject::GetNumChildren (this=0x1d6c620,
> max=4294967295) at
> ../../git/llvm/tools/lldb/source/Core/ValueObject.cpp:601
> lldb_private::FormatManager::ShouldPrintAsOneLiner
> (this=0x7fe7676031d8 <GetFormatManager()::g_format_manager>,
> valobj=...) at
> ../../git/llvm/tools/lldb/source/DataFormatters/FormatManager.cpp:494
> lldb_private::DataVisualization::ShouldPrintAsOneLiner (valobj=...) at
> ../../git/llvm/tools/lldb/source/DataFormatters/DataVisualization.cpp:33
> lldb_private::ValueObjectPrinter::PrintChildrenIfNeeded
> (this=0x7fff14ce0560, value_printed=true, summary_printed=false) at
> ../../git/llvm/tools/lldb/source/DataFormatters/ValueObjectPrinter.cpp:771
> lldb_private::ValueObjectPrinter::PrintValueObject
> ...
> lldb_private::ValueObject::Dump (this=0x1d6c620, s=..., options=...)
> at ../../git/llvm/tools/lldb/source/Core/ValueObject.cpp:2742
> lldb_private::CommandObjectExpression::EvaluateExpression
>
>
>
> (4)
> ==== ASTContext B, "From" ASTContext Y, MINIMAL import, skips
> ExternalASTSource interface
> clang::ASTImporter::Import (this=0x1d74cd0, FromT=...) at
> ../../git/llvm/tools/clang/lib/AST/ASTImporter.cpp:6983
> lldb_private::ClangASTImporter::CopyType (this=0x1c96360,
> dst_ast=0x1cde470, src_ast=0x1d5bf60, type=...) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:61
> lldb_private::ClangASTImporter::CopyType (this=0x1c96360,
> dst_ast=0x1cde470, src_ast=0x1d5bf60, type=0x1daad10) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:70
> lldb_private::ClangASTImporter::DeportType (this=0x1c96360,
> dst_ctx=0x1cde470, src_ctx=0x1d5bf60, type=0x1daad10) at
> ../../git/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:268
> lldb_private::ClangExpressionDeclMap::DeportType (this=0x1c98e00,
> target=..., source=..., parser_type=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:288
> lldb_private::ClangExpressionDeclMap::AddPersistentVariable
> (this=0x1c98e00, decl=0x1daaff8, name=..., parser_type=...,
> is_result=true, is_lvalue=true) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:332
> IRForTarget::CreateResultVariable (this=0x7fff14cdf8c0,
> llvm_function=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp:407
> IRForTarget::runOnModule (this=0x7fff14cdf8c0, llvm_module=...) at
>
> ../../git/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp:2102
> lldb_private::ClangExpressionParser::PrepareForExecution
> ...
> lldb_private::CommandObjectExpression::EvaluateExpression
> (this=0x1a953b0, expr=0x7fff14ce0d58 "tpi",
> output_stream=0x7fff14ce16e8, error_stream=0x7fff14ce1740,
> result=0x7fff14ce16e8) at
> ../../git/llvm/tools/lldb/source/Commands/CommandObjectExpression.cpp:377
>
>
> On Wed, Aug 15, 2018 at 2:52 AM Lang Hames <lhames at gmail.com> wrote:
> >
> > Hi Gábor, Richard,
> >
> >> Hi Richard, maybe my understanding is not correct, but I believe the
> >> situation is somewhat twisted and reversed...
> >
> >
> > Is this relationship recursive? (Should it be?) I.e. When ClangASTSource
> uses ASTImporter to minimally import a Decl, should that Decl have another
> ExternalASTSource attached (possibly the original ClangASTSource) to
> complete the minimally imported Decl on demand?
> >
> > -- Lang.
> >
> > On Tue, Aug 14, 2018 at 6:49 AM Gábor Márton <martongabesz at gmail.com>
> wrote:
> >>
> >> > It might be interesting to consider how this is addressed by the
> ExternalASTSource interface. There, we have separate "import the lexical
> contents of this AST node (including populating the lexical declarations
> list with all members, in the right order)", "import the lookup results for
> this name in this context (and cache them but don't add them to the list of
> lexical members)" and "import this specific declaration member (but don't
> add it to the list of lexical members)" queries. One could imagine doing
> something similar for the AST importer: when you're performing a minimal
> import but you want to import a method declaration, don't insert it into
> the list of lexical members of the enclosing record. Instead, defer doing
> that until a complete type is required (at that point, you'd need to import
> all the relevant members anyway, including the base classes and virtual
> functions in the right order).
> >>
> >> Hi Richard, maybe my understanding is not correct, but I believe the
> >> situation is somewhat twisted and reversed.
> >> Seems like LLDB already exercises the ExternalASTSource interface. The
> >> purpose of using it is exactly to load the external lexical contents
> >> of an AST node (as you suggested). However, the load is implemented by
> >> the means of the ASTImporter (in minimal mode). Consider the attached
> >> function call trace:
> >> When the user instructs LLDB to evaluate an expression then LLDB
> >> exercises the parser `clang::ParseAST`, which in turn does a lookup
> >> `clang::DeclContext::lookup`. During the lookup,
> >> `lldb_private::ClangASTSource::FindExternalVisibleDeclsByName` is
> >> called (this function overloads
> >> `ExternalASTSource::FindExternalVisibleDeclsByName`).
> >> And finally, through `lldb_private::ClangASTImporter::CopyType` we end
> >> up in `clang::ASTImporter::Import`.
> >>
> >> Gabor
> >>
> >> ```
> >> #4 0x00007ffff41a72ed in clang::ASTNodeImporter::ImportDeclParts
> >> (this=this at entry=0x7fffffff8be0, D=D at entry=0x632038,
> >> DC=@0x7fffffff8ac8: 0x0,
> >> LexicalDC=@0x7fffffff8ad0: 0x0, Name=..., ToD=@0x7fffffff8ad8: 0x0,
> Loc=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/AST/ASTImporter.cpp:1062
> >> #5 0x00007ffff41a8d55 in clang::ASTNodeImporter::VisitRecordDecl
> >> (this=0x7fffffff8be0, D=0x632038)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/AST/ASTImporter.cpp:2126
> >> #6 0x00007ffff419377b in clang::ASTImporter::Import (this=0x70cc90,
> >> FromD=0x632038)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/AST/ASTImporter.cpp:7054
> >> #7 0x00007ffff41939f7 in clang::ASTNodeImporter::VisitRecordType
> >> (this=0x7fffffff8c40, T=<optimized out>)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/AST/ASTImporter.cpp:851
> >> #8 0x00007ffff4196f65 in clang::TypeVisitor<clang::ASTNodeImporter,
> >> clang::QualType>::Visit (this=this at entry=0x7fffffff8c40, T=<optimized
> >> out>)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/include/clang/AST/TypeNodes.def:92
> >> #9 0x00007ffff4197187 in clang::ASTImporter::Import (this=0x70cc90,
> >> FromT=FromT at entry=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/AST/ASTImporter.cpp:6983
> >> #10 0x00007ffff7351c92 in lldb_private::ClangASTImporter::CopyType
> >> (this=<optimized out>, dst_ast=<optimized out>, src_ast=<optimized
> >> out>, type=type at entry=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Symbol/ClangASTImporter.cpp:61
> >> #11 0x00007ffff74bdb95 in
> >> lldb_private::ClangASTSource::GuardedCopyType
> >> (this=this at entry=0x611e20, src_type=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:2040
> >> #12 0x00007ffff74e9ffe in
> >> lldb_private::ClangExpressionDeclMap::GetVariableValue
> >> (this=this at entry=0x611e20, var=std::shared_ptr (count 6, weak 1)
> >> 0x7fffe80020f0,
> >> var_location=..., user_type=user_type at entry=0x7fffffff8fc0,
> >> parser_type=parser_type at entry=0x7fffffff8fe0)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:1627
> >> #13 0x00007ffff74ea3a7 in
> >> lldb_private::ClangExpressionDeclMap::AddOneVariable
> >> (this=this at entry=0x611e20, context=...,
> >> var=std::shared_ptr (count 6, weak 1) 0x7fffe80020f0, valobj=...,
> >> current_id=current_id at entry=2)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:1679
> >> #14 0x00007ffff74ec50b in
> >> lldb_private::ClangExpressionDeclMap::FindExternalVisibleDecls
> >> (this=this at entry=0x611e20, context=..., module_sp=
> >> std::shared_ptr (empty) 0x0, namespace_decl=...,
> >> current_id=current_id at entry=2)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:1240
> >> #15 0x00007ffff74ef4ce in
> >> lldb_private::ClangExpressionDeclMap::FindExternalVisibleDecls
> >> (this=0x611e20, context=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp:843
> >> #16 0x00007ffff74c71cc in
> >> lldb_private::ClangASTSource::FindExternalVisibleDeclsByName
> >> (this=0x611e20, decl_ctx=0x71d8b8, clang_decl_name=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp:261
> >> #17 0x00007ffff421d92d in clang::DeclContext::lookup
> >> (this=this at entry=0x71d8b8, Name=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/AST/DeclBase.cpp:1577
> >> #18 0x00007ffff4d4bb42 in LookupDirect (S=..., R=..., DC=DC at entry
> =0x71d8b8)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Sema/SemaLookup.cpp:843
> >> #19 0x00007ffff4d52f50 in CppNamespaceLookup (S=..., R=...,
> >> NS=NS at entry=0x71d8b8, UDirs=..., Context=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Sema/SemaLookup.cpp:942
> >> #20 0x00007ffff4d53925 in clang::Sema::CppLookupName
> >> (this=this at entry=0x7245b0, R=..., S=0x72cad0)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Sema/SemaLookup.cpp:1322
> >> #21 0x00007ffff4d53c8a in clang::Sema::LookupName (this=0x7245b0,
> >> R=..., S=0x7314f0, AllowBuiltinCreation=<optimized out>)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Sema/SemaLookup.cpp:1827
> >> #22 0x00007ffff4b6b945 in clang::Sema::ClassifyName (this=0x7245b0,
> >> S=0x7314f0, SS=..., Name=@0x7fffffffa3a8: 0x750dc8, NameLoc=...,
> >> NameLoc at entry=...,
> >> NextToken=..., IsAddressOfOperand=false,
> >> CCC=std::unique_ptr<clang::CorrectionCandidateCallback> containing
> >> 0x63c250)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Sema/SemaDecl.cpp:868
> >> #23 0x00007ffff52c6a9f in clang::Parser::TryAnnotateName
> >> (this=this at entry=0x728c60,
> >> IsAddressOfOperand=IsAddressOfOperand at entry=false,
> >> CCC=std::unique_ptr<clang::CorrectionCandidateCallback> containing
> >> 0x0) at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/Parser.cpp:1531
> >> #24 0x00007ffff52aa56b in
> >> clang::Parser::ParseStatementOrDeclarationAfterAttributes
> >> (this=this at entry=0x728c60, Stmts=...,
> >> Allowed=Allowed at entry=clang::Parser::ACK_Any,
> >> TrailingElseLoc=<optimized out>, Attrs=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/ParseStmt.cpp:189
> >> #25 0x00007ffff52aa843 in clang::Parser::ParseStatementOrDeclaration
> >> (this=this at entry=0x728c60, Stmts=...,
> >> Allowed=Allowed at entry=clang::Parser::ACK_Any,
> >> TrailingElseLoc=TrailingElseLoc at entry=0x0) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/ParseStmt.cpp:111
> >> #26 0x00007ffff52ae577 in clang::Parser::ParseCompoundStatementBody
> >> (this=this at entry=0x728c60, isStmtExpr=isStmtExpr at entry=false)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/ParseStmt.cpp:1003
> >> #27 0x00007ffff52b0a49 in clang::Parser::ParseFunctionStatementBody
> >> (this=this at entry=0x728c60, Decl=Decl at entry=0x72dbd0, BodyScope=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/ParseStmt.cpp:1972
> >> #28 0x00007ffff52cc6e0 in clang::Parser::ParseFunctionDefinition
> >> (this=this at entry=0x728c60, D=..., TemplateInfo=...,
> >> LateParsedAttrs=LateParsedAttrs at entry=0x7fffffffabe0) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/Parser.cpp:1248
> >> #29 0x00007ffff524aa56 in clang::Parser::ParseDeclGroup
> >> (this=this at entry=0x728c60, DS=...,
> >> Context=Context at entry=clang::DeclaratorContext::FileContext,
> >> DeclEnd=DeclEnd at entry=0x0, FRI=FRI at entry=0x0) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/ParseDecl.cpp:1968
> >> #30 0x00007ffff52c7f90 in
> >> clang::Parser::ParseDeclOrFunctionDefInternal
> >> (this=this at entry=0x728c60, attrs=..., DS=...,
> >> AS=AS at entry=clang::AS_none)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/Parser.cpp:1012
> >> #31 0x00007ffff52c8761 in
> >> clang::Parser::ParseDeclarationOrFunctionDefinition (this=0x728c60,
> >> attrs=..., AS=clang::AS_none, DS=0x0)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/Parser.cpp:1028
> >> #32 0x00007ffff52c87bf in
> >> clang::Parser::ParseDeclarationOrFunctionDefinition (this=<optimized
> >> out>, attrs=..., DS=<optimized out>, AS=<optimized out>)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/Parser.cpp:1030
> >> #33 0x00007ffff52cd05d in clang::Parser::ParseExternalDeclaration
> >> (this=this at entry=0x728c60, attrs=..., DS=DS at entry=0x0)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/Parser.cpp:853
> >> #34 0x00007ffff52ce05c in clang::Parser::ParseTopLevelDecl
> >> (this=this at entry=0x728c60, Result=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/Parser.cpp:609
> >> #35 0x00007ffff522ce1b in clang::ParseAST (S=...,
> >> PrintStats=PrintStats at entry=false,
> >> SkipFunctionBodies=SkipFunctionBodies at entry=false)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/ParseAST.cpp:146
> >> #36 0x00007ffff522d0e0 in clang::ParseAST (PP=..., Consumer=0x535f70,
> >> Ctx=..., PrintStats=<optimized out>, TUKind=clang::TU_Complete,
> >> CompletionConsumer=0x0,
> >> SkipFunctionBodies=false) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/clang/lib/Parse/ParseAST.cpp:110
> >> #37 0x00007ffff74f0059 in lldb_private::ClangExpressionParser::Parse
> >> (this=this at entry=0x7fffffffcae0, diagnostic_manager=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp:619
> >> #38 0x00007ffff74d23ad in lldb_private::ClangUserExpression::Parse
> >> (this=0x6d23c0, diagnostic_manager=..., exe_ctx=...,
> >> execution_policy=lldb_private::eExecutionPolicyOnlyWhenNeeded,
> >> keep_result_in_memory=<optimized out>, generate_debug_info=<optimized
> >> out>)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp:472
> >> ---Type <return> to continue, or q <return> to quit---
> >> #39 0x00007ffff72cea9e in lldb_private::UserExpression::Evaluate
> >> (exe_ctx=..., options=..., expr=..., prefix=..., result_valobj_sp=...,
> >> error=..., line_offset=0,
> >> fixed_expression=0x4bced8, jit_module_sp_ptr=0x0) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Expression/UserExpression.cpp:239
> >> #40 0x00007ffff7401996 in lldb_private::Target::EvaluateExpression
> >> (this=this at entry=0x5b8d10, expr=..., exe_scope=<optimized out>,
> >> result_valobj_sp=...,
> >> options=..., fixed_expression=0x4bced8) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Target/Target.cpp:2321
> >> #41 0x00007ffff77912dd in
> >> lldb_private::CommandObjectExpression::EvaluateExpression
> >> (this=this at entry=0x4bcb50, expr=expr at entry=0x7fffffffd4c0 "val.v",
> >> output_stream=output_stream at entry=0x7fffffffd5f0,
> >> error_stream=error_stream at entry=0x7fffffffd648,
> >> result=result at entry=0x7fffffffd5f0)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Commands/CommandObjectExpression.cpp:377
> >> #42 0x00007ffff7792018 in
> >> lldb_private::CommandObjectExpression::DoExecute (this=0x4bcb50,
> >> command=0x7fffffffd4c0 "val.v", result=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Commands/CommandObjectExpression.cpp:625
> >> #43 0x00007ffff7305baa in lldb_private::CommandObjectRaw::Execute
> >> (this=0x4bcb50, args_string=0x7fffffffd4c0 "val.v", result=...)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Interpreter/CommandObject.cpp:1013
> >> #44 0x00007ffff7302e1b in
> >> lldb_private::CommandInterpreter::HandleCommand
> >> (this=this at entry=0x4a8740, command_line=<optimized out>,
> >> lazy_add_to_history=lazy_add_to_history at entry
> =lldb_private::eLazyBoolCalculate,
> >> result=..., override_context=override_context at entry=0x0,
> >> repeat_on_empty_command=repeat_on_empty_command at entry=true,
> >> no_context_switching=false)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Interpreter/CommandInterpreter.cpp:1683
> >> #45 0x00007ffff73047c8 in
> >> lldb_private::CommandInterpreter::IOHandlerInputComplete
> >> (this=0x4a8740, io_handler=..., line="expr val.v")
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Interpreter/CommandInterpreter.cpp:2771
> >> #46 0x00007ffff723e241 in lldb_private::IOHandlerEditline::Run
> (this=0x5b4da0)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Core/IOHandler.cpp:573
> >> #47 0x00007ffff720a820 in lldb_private::Debugger::ExecuteIOHandlers
> >> (this=0x4a6f90)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Core/Debugger.cpp:961
> >> #48 0x00007ffff72f731f in
> >> lldb_private::CommandInterpreter::RunCommandInterpreter
> >> (this=0x4a8740, auto_handle_events=auto_handle_events at entry=true,
> >> spawn_thread=spawn_thread at entry=false, options=...) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/Interpreter/CommandInterpreter.cpp:2971
> >> #49 0x00007ffff7094776 in lldb::SBDebugger::RunCommandInterpreter
> >> (this=this at entry=0x7fffffffda60,
> >> auto_handle_events=auto_handle_events at entry=true,
> >> spawn_thread=spawn_thread at entry=false) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/source/API/SBDebugger.cpp:892
> >> #50 0x0000000000404a76 in Driver::MainLoop (this=this at entry
> =0x7fffffffda40)
> >> at
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/tools/driver/Driver.cpp:1156
> >> #51 0x0000000000403724 in main (argc=2, argv=0x7fffffffdcb8) at
> >>
> /home/gerazo/repos/codechecker_dev_env/CTU/llvm/tools/lldb/tools/driver/Driver.cpp:1253
> >>
> >> ```
> >> On Tue, Aug 14, 2018 at 2:34 AM Richard Smith via cfe-dev
> >> <cfe-dev at lists.llvm.org> wrote:
> >> >
> >> > On Mon, 13 Aug 2018 at 17:08, Lang Hames via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
> >> >>
> >> >> Hi Richard,
> >> >>
> >> >>> Perhaps a better approach would be to make the "minimal" mode for
> the ASTImporter provide an ExternalASTSource to lazily complete the AST as
> needed (thereby avoiding violating the invariant, because you would
> populate the lexical declarations list whenever anyone actually asks for
> it).
> >> >>
> >> >>
> >> >> This seems worth investigating. I wonder if it might also fix
> another bug that I know of involving virtual methods with covariant return
> types. (You and I actually discussed it at one of the socials a while back,
> but I have not had time to dig into it further.)
> >> >>
> >> >> The reproducer for the bug is:
> >> >>
> >> >> class Foo {};
> >> >> class Bar : public Foo {};
> >> >>
> >> >> class Base {
> >> >> public:
> >> >> virtual Foo* foo() { return nullptr; }
> >> >> };
> >> >>
> >> >> class Derived : public Base {
> >> >> public:
> >> >> virtual Bar* foo() { return nullptr; }
> >> >> };
> >> >>
> >> >> int main() {
> >> >> Derived D;
> >> >> D.foo(); // Evaluate 'D.foo()' here, crash LLDB.
> >> >> }
> >> >>
> >> >> The issue is that since Bar's definition is not used its bases are
> never imported, and so the call to Bar::bases() crashes in CodeGen. If we
> provided an ExternalASTSource, would that be able to lazily complete the
> bases?
> >> >
> >> >
> >> > Yes, such an approach should be able to solve that problem too: when
> CodeGen (or indeed anything) queries any property of the definition of Foo
> / Bar (including whether a definition exists), you'll get a callback and a
> chance to provide a complete type.
> >> >
> >> >>
> >> >> Cheers,
> >> >> Lang.
> >> >>
> >> >>
> >> >> On Mon, Aug 13, 2018 at 3:30 PM Richard Smith <richard at metafoo.co.uk>
> wrote:
> >> >>>
> >> >>> On Thu, 9 Aug 2018 at 10:47, Lang Hames via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
> >> >>>>
> >> >>>> Hi clang-dev, lldb-dev,
> >> >>>>
> >> >>>> It looks like my clang commit r305850, which modified ASTImporter
> to import method override tables from an external context, introduced a new
> bug which manifests as incorrect vtable layouts for LLDB expression code.
> >> >>>>
> >> >>>> The bug itself is fairly straightforward. In r305850 I introduced
> the following method, which is called from
> ASTNodeImporter::VisitFunctionDecl:
> >> >>>>
> >> >>>> void ASTNodeImporter::ImportOverrides(CXXMethodDecl *ToMethod,
> >> >>>> CXXMethodDecl *FromMethod) {
> >> >>>> for (auto *FromOverriddenMethod :
> FromMethod->overridden_methods())
> >> >>>> ToMethod->addOverriddenMethod(
> >> >>>>
> cast<CXXMethodDecl>(Importer.Import(const_cast<CXXMethodDecl*>(
> >> >>>>
> FromOverriddenMethod))));
> >> >>>> }
> >> >>>>
> >> >>>> This will produce the correct override table, but can also cause
> methods in the Base class to be visited in the wrong order. Consider:
> >> >>>>
> >> >>>> class Base {
> >> >>>> public:
> >> >>>> virtual void bar() {}
> >> >>>> virtual void foo() {}
> >> >>>> };
> >> >>>>
> >> >>>> class Derived : public Base {
> >> >>>> public:
> >> >>>> void foo() override {}
> >> >>>> };
> >> >>>>
> >> >>>> If Derived is imported into a new context before Base, then the
> importer will visit Derived::foo, and (via ImportOverrides) immediately
> import Base::foo, but this happens before Base::bar is imported. As a
> consequence, the decl order on the imported Base class will end up being [
> foo, bar ], instead of [ bar, foo ]. In LLDB expression evaluation this
> manifests as an incorrect vtable layout for Base, with foo occupying the
> first slot.
> >> >>>>
> >> >>>> I am looking for suggestions on the right way to fix this. A brute
> force solution might be to always have ASTNodeImporter::VisitRecordDecl
> visit all base classes, then all virtual methods, which would ensure they
> are visited in the original decl order. However I do not know whether this
> covers all paths by which a CXXRecordDecl might be imported, nor whether
> the performance of this solution would be acceptable (it seems like it
> would preclude a lot of laziness).
> >> >>>>
> >> >>>> Alternatively we might be able to associate an index with each
> imported decl and sort on that when we complete the type, but that would
> leave imported decls in the wrong order until the type was complete, and
> since I do not know all the use cases for the importer I'm concerned people
> may rely on the decl order before type is complete.
> >> >>>>
> >> >>>> Any insight from ASTImporter experts would be greatly appreciated.
> :)
> >> >>>
> >> >>>
> >> >>> Hi Lang,
> >> >>>
> >> >>> It might be interesting to consider how this is addressed by the
> ExternalASTSource interface. There, we have separate "import the lexical
> contents of this AST node (including populating the lexical declarations
> list with all members, in the right order)", "import the lookup results for
> this name in this context (and cache them but don't add them to the list of
> lexical members)" and "import this specific declaration member (but don't
> add it to the list of lexical members)" queries. One could imagine doing
> something similar for the AST importer: when you're performing a minimal
> import but you want to import a method declaration, don't insert it into
> the list of lexical members of the enclosing record. Instead, defer doing
> that until a complete type is required (at that point, you'd need to import
> all the relevant members anyway, including the base classes and virtual
> functions in the right order).
> >> >>>
> >> >>> The above approach would violate AST invariants (you'd have a
> declaration whose lexical parent doesn't believe it lexically contains the
> child), but I don't know off-hand whether that would be problematic.
> Perhaps a better approach would be to make the "minimal" mode for the
> ASTImporter provide an ExternalASTSource to lazily complete the AST as
> needed (thereby avoiding violating the invariant, because you would
> populate the lexical declarations list whenever anyone actually asks for
> it).
> >> >>
> >> >> _______________________________________________
> >> >> cfe-dev mailing list
> >> >> cfe-dev at lists.llvm.org
> >> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> >> >
> >> > _______________________________________________
> >> > cfe-dev mailing list
> >> > cfe-dev at lists.llvm.org
> >> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
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