LLDB uses clang::DeclContexts for lookups, and variables get put into
the DeclContext for their abstract origin. (The abstract origin is a
DWARF pointer that indicates the unique definition of inlined code.)
When the expression parser is looking for variables, it locates the
DeclContext for the current context. This needs to be done carefully,
though, e.g.:
__attribute__ ((always_inline)) void f(int a) {
{
int b = a * 2;
}
}
void g() {
f(3);
}
Here, if we're stopped in the inlined copy of f, we have to find the
DeclContext corresponding to the definition of f – its abstract
origin. Clang doesn't allow multiple functions with the same name and
arguments to exist. It also means that any variables we see must be
placed in the appropriate DeclContext.
[Bug 1]: When stopped in an inline block, the function
GetDeclContextDIEContainingDIE for that block doesn't properly
construct a DeclContext for the abstract origin for inlined
subroutines. That means we get duplicated function DeclContexts, but
function arguments only get put in the abstract origin's DeclContext,
and as a result when we try to look for them in nested contexts they
aren't found.
[Bug 2]: When stopped in an inline block, the DWARF (for space
reasons) doesn't explicitly point to the abstract origin for that
block. This means that the function GetClangDeclContextForDIE returns
a different DeclContext for each place the block is inlined. However,
any variables defined in the block have abstract origins, so they
will only get placed in the DeclContext for their abstract origin.
In this fix, I've introduced a test covering both of these issues,
and fixed them.
Bug 1 could be resolved simply by making sure we look up the abstract
origin for inlined functions when looking up their DeclContexts on
behalf of nested blocks.
For Bug 2, I've implemented an algorithm that makes the DeclContext
for a block be the containing DeclContext for the closest entity we
would find during lookup that has an abstract origin pointer. That
means that in the following situation:
{ // block 1
int a;
{ // block 2
int b;
}
}
if we looked up the DeclContext for block 2, we'd find the block
containing the abstract origin of b, and lookup would proceed
correctly because we'd see b and a. However, in the situation
{ // block 1
int a;
{ // block 2
}
}
since there isn't anything to look up in block 2, we can't determine
its abstract origin (and there is no such pointer in the DWARF for
blocks). However, we can walk up the parent chain and find a, and its
abstract origin lives in the abstract origin of block 1. So we simply
say that the DeclContext for block 2 is the same as the DeclContext
for block 1, which contains a. Lookups will return the same results.
Thanks to Jim Ingham for review and suggestions.
Differential revision: https://reviews.llvm.org/D32375
llvm-svn: 301263
*** to conform to clang-format’s LLVM style. This kind of mass change has
*** two obvious implications:
Firstly, merging this particular commit into a downstream fork may be a huge
effort. Alternatively, it may be worth merging all changes up to this commit,
performing the same reformatting operation locally, and then discarding the
merge for this particular commit. The commands used to accomplish this
reformatting were as follows (with current working directory as the root of
the repository):
find . \( -iname "*.c" -or -iname "*.cpp" -or -iname "*.h" -or -iname "*.mm" \) -exec clang-format -i {} +
find . -iname "*.py" -exec autopep8 --in-place --aggressive --aggressive {} + ;
The version of clang-format used was 3.9.0, and autopep8 was 1.2.4.
Secondly, “blame” style tools will generally point to this commit instead of
a meaningful prior commit. There are alternatives available that will attempt
to look through this change and find the appropriate prior commit. YMMV.
llvm-svn: 280751
This allows these functions to be re-used by a forthcoming
PDBASTParser. The functions in question are CanCompleteType,
CompleteType, and CanImport. Conceptually, these functions belong
on ClangASTImporter anyway, and previously they were just ping
ponging around through a few levels of indirection to end up there
as well, so this patch actually makes the code somewhat simpler.
A few methods were moved to a new file called ClangUtil, so that
they can be shared between ClangASTImporter and ClangASTContext
without creating a circular dependency between those two cpp
files.
Differential Revision: http://reviews.llvm.org/D18381
llvm-svn: 264685
1) Turns out we weren't correctly uniquing types for C++. We would search our repository for "lldb_private::Process", but yet store just "Process" in the unique type map. Now we store things correctly and correctly unique types.
2) SymbolFileDWARF::CompleteType() can be called at any time in order to complete a C++ or Objective C class. All public inquiries into the SymbolFile go through SymbolVendor, and SymbolVendor correctly takes the module lock before it call the SymbolFile API call, but when we let CompilerType objects out in the wild, they can complete themselves at any time from the expression parser, so the ValueObjects or (SBValue objects in the public API), and many more places. So we now take the module lock when completing a type to avoid two threads being in the SymbolFileDWARF at the same time.
3) If a class has a template member function like:
class A
{
<template T>
void Foo(T t);
};
The DWARF will _only_ contain a DW_TAG_subprogram for "Foo" if anyone specialized it. This would cause a class definition for A inside a.cpp that used a "int" and "float" overload to look like:
class A
{
void Foo(int t);
void Foo(double t);
};
And a version from b.cpp that used a "float" overload to look like:
class A
{
void Foo(float t);
};
And a version from c.cpp that use no overloads to look like:
class A
{
};
Then in an expression if you have two variables, one name "a" from a.cpp in liba.dylib, and one named "b" from b.cpp in libb.dylib, you will get conflicting definitions for "A" and your expression will fail. This all stems from the fact that DWARF _only_ emits template specializations, not generic definitions, and they are only emitted if they are used. There are two solutions to this:
a) When ever you run into ANY class, you must say "just because this class doesn't have templatized member functions, it doesn't mean that any other instances might not have any, so when ever I run into ANY class, I must parse all compile units and parse all instances of class "A" just in case it has member functions that are templatized.". That is really bad because it means you always pull in ALL DWARF that contains most likely exact duplicate definitions of the class "A" and you bloat the memory that the SymbolFileDWARF plug-in uses in LLDB (since you pull in all DIEs from all compile units that contain a "A" definition) uses for little value most of the time.
b) Modify DWARF to emit generic template member function definitions so that you know from looking at any instance of class "A" wether it has template member functions or not. In order to do this, we would have to have the ability to correctly parse a member function template, but there is a compiler bug:
<rdar://problem/24515533> [PR 26553] C++ Debug info should reference DW_TAG_template_type_parameter
This bugs means that not all of the info needed to correctly make a template member function is in the DWARF. The main source of the problem is if we have DWARF for a template instantiation for "int" like: "void A::Foo<int>(T)" the DWARF comes out as "void A::Foo<int>(int)" (it doesn't mention type "T", it resolves the type to the specialized type to "int"). But if you actually have your function defined as "<template T> void Foo(int t)" and you only use T for local variables inside the function call, we can't correctly make the function prototype up in the clang::ASTContext.
So the best we can do for now we just omit all member functions that are templatized from the class definition so that "A" never has any template member functions. This means all defintions of "A" look like:
class A
{
};
And our expressions will work. You won't be able to call template member fucntions in expressions (not a regression, we weren't able to do this before) and if you are stopped in a templatized member function, we won't know that are are in a method of class "A". All things we should fix, but we need <rdar://problem/24515533> fixed first, followed by:
<rdar://problem/24515624> Classes should always include a template subprogram definition, even when no template member functions are used
before we can do anything about it in LLDB.
This bug mainly fixed the following Apple radar:
<rdar://problem/24483905>
llvm-svn: 260308
It was previously reverted due to issues that showed up only on linux. I was able to reproduce these issues and fix the underlying cause.
So this is the same patch as 254476 with the following two fixes:
- Fix not trying to complete classes that don't have external sources
- Fix ClangASTSource::CompleteType() to check the decl context of types that it finds by basename to ensure we don't complete a type "S" with a type like "std::S". Before this fix ClangASTSource::CompleteType() would accept _any_ type that had a matching basename and copy it into the other type.
<rdar://problem/22992457>
llvm-svn: 254980
This is done by finding the types that are forward declarations that come from a module, and loading that module's debug info in a separate lldb_private::Module, and copying the type over into the current module using a ClangASTImporter object. ClangASTImporter objects are already used to copy types from on clang::ASTContext to another for expressions so the type copying code has been around for a while.
A new FindTypes variant was added to SymbolVendor and SymbolFile:
size_t
SymbolVendor::FindTypes (const std::vector<CompilerContext> &context, bool append, TypeMap& types);
size_t
SymbolVendor::FindTypes (const std::vector<CompilerContext> &context, bool append, TypeMap& types);
The CompilerContext is a way to represent the exact context of a type and pass it through an agnostic API boundary so that we can find that exact context elsewhere in another file. This was required here because we can have a module that has submodules, both of which have a "foo" type.
I am not able to add tests for this yet as we currently don't build our C/C++/ObjC binaries with the clang binary that we build. There are some driver issues where it can't find the header files for the C and C++ standard library which makes compiling these tests hard. We can't also guarantee that if we are building with clang that it supporst the exact format of -gmodule debugging that we are trying to test. We have had other versions of clang that had a different implementation of -gmodule debugging that we are no longer supporting, so we can't enable tests if we are building with clang without compiling something and looking at the structure of the DWARF that was generated to ensure that it is the format we can actually use.
llvm-svn: 254476
Summary:
With this change DWARFASTParserClang::CompleteTypeFromDWARF returns false if
DWARFASTParserClang::ParseChildMembers returns false. Similarly, it returns
false if any base class is of an incomplete type. This helps in cases like
these:
class Foo
{
public:
std::string str;
};
...
Foo f;
If a file with the above code is compiled with a modern clang but without
the -fno-limit-debug-info (or similar) option, then the DWARF has only
a forward declration for std::string. In which case, the type for
"class Foo" cannot be completed. If LLDB does not detect that a child
member has incomplete type, then it wrongly conveys to clang (the LLDB
compiler) that "class Foo" is complete, and consequently crashes due to
an assertion failure in clang when running commands like "p f" or
"frame var f".
Reviewers: clayborg
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D13066
llvm-svn: 248401
Summary: Supports the parsing of the "using namespace XXX" and "using XXX::XXX" directives. Added ambiguity errors when it two decls with the same name are encountered (see comments in TestCppNsImport). Fixes using directives being duplicated for anonymous namespaces. Fixes GetDeclForUID for specification DIEs.
Reviewers: sivachandra, chaoren, clayborg
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D12897
llvm-svn: 247836
Summary: SymbolFileDWARF now creates VarDecl and BlockDecl and adds them to the Decl tree. Then, in ClangExpressionDeclMap it uses the Decl tree to search for a variable. This fixes lots of variable scoping problems.
Reviewers: sivachandra, chaoren, spyffe, clayborg
Subscribers: tberghammer, jingham, lldb-commits
Differential Revision: http://reviews.llvm.org/D12658
llvm-svn: 247746
class DWARFASTParser
{
public:
virtual ~DWARFASTParser() {}
virtual lldb::TypeSP
ParseTypeFromDWARF (const lldb_private::SymbolContext& sc,
const DWARFDIE &die,
lldb_private::Log *log,
bool *type_is_new_ptr) = 0;
virtual lldb_private::Function *
ParseFunctionFromDWARF (const lldb_private::SymbolContext& sc,
const DWARFDIE &die) = 0;
virtual bool
CompleteTypeFromDWARF (const DWARFDIE &die,
lldb_private::Type *type,
lldb_private::CompilerType &clang_type) = 0;
virtual lldb_private::CompilerDeclContext
GetDeclContextForUIDFromDWARF (const DWARFDIE &die) = 0;
virtual lldb_private::CompilerDeclContext
GetDeclContextContainingUIDFromDWARF (const DWARFDIE &die) = 0;
};
We have one subclass named DWARFASTParserClang that implements all of the clang specific AST type parsing. This keeps all DWARF parsing in the DWARF plug-in. Moved all of the DWARF parsing code that was in ClangASTContext over into DWARFASTParserClang.
lldb_private::TypeSystem classes no longer have any DWARF parsing functions in them, but they can hand out a DWARFASTParser:
virtual DWARFASTParser *
GetDWARFParser ()
{
return nullptr;
}
This keeps things clean and makes for easy merging when we have different AST's for different languages.
llvm-svn: 246242
Sean Callanan