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Use an artifical namespace so that member vars do not hide local vars. 

Summary:
While evaluating expressions when stopped in a class method, there was a
problem of member variables hiding local variables. This was happening
because, in the context of a method, clang already knew about member
variables with their name and assumed that they were the only variables
with those names in scope. Consequently, clang never checks with LLDB
about the possibility of local variables with the same name and goes
wrong. This change addresses the problem by using an artificial
namespace "$__lldb_local_vars". All local variables in scope are
declared in the "$__lldb_expr" method as follows:

    using $__lldb_local_vars::<local var 1>;
    using $__lldb_local_vars::<local var 2>;
    ...

This hides the member variables with the same name and forces clang to
enquire about the variables which it thinks are declared in
$__lldb_local_vars. When LLDB notices that clang is enquiring about
variables in $__lldb_local_vars, it looks up local vars and conveys
their information if found. This way, member variables do not hide local
variables, leading to correct evaluation of expressions.

A point to keep in mind is that the above solution does not solve the
problem for one specific case:

    namespace N
    {
        int a;
    }

    class A
    {
    public:
        void Method();
        int a;
    };

    void
    A::Method()
    {
        using N::a;
        ...

        // Since the above solution only touches locals, it does not
        // force clang to enquire about "a" coming from namespace N.
    }

Reviewers: clayborg, spyffe

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D16746

llvm-svn: 259810
This commit is contained in:
Siva Chandra 2016-02-04 18:38:35 +00:00
parent 76c48e0e70
commit 375882dddb
12 changed files with 409 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
lldb/include/lldb/Symbol/ClangASTContext.h
View File

@ -422,6 +422,11 @@ public:
GetUniqueNamespaceDeclaration (const char *name,
clang::DeclContext *decl_ctx);
static clang::NamespaceDecl *
GetUniqueNamespaceDeclaration (clang::ASTContext *ast,
const char *name,
clang::DeclContext *decl_ctx);
//------------------------------------------------------------------
// Function Types
//------------------------------------------------------------------
@ -565,7 +570,9 @@ public:
//----------------------------------------------------------------------
std::vector<CompilerDecl>
DeclContextFindDeclByName (void *opaque_decl_ctx, ConstString name) override;
DeclContextFindDeclByName (void *opaque_decl_ctx,
ConstString name,
const bool ignore_using_decls) override;
bool
DeclContextIsStructUnionOrClass (void *opaque_decl_ctx) override;

2
lldb/include/lldb/Symbol/CompilerDeclContext.h
View File

@ -66,7 +66,7 @@ public:
IsClang () const;
std::vector<CompilerDecl>
FindDeclByName (ConstString name);
FindDeclByName (ConstString name, const bool ignore_using_decls);
//----------------------------------------------------------------------
/// Checks if this decl context represents a method of a class.

4
lldb/include/lldb/Symbol/TypeSystem.h
View File

@ -143,7 +143,9 @@ public:
//----------------------------------------------------------------------
virtual std::vector<CompilerDecl>
DeclContextFindDeclByName (void *opaque_decl_ctx, ConstString name);
DeclContextFindDeclByName (void *opaque_decl_ctx,
ConstString name,
const bool ignore_imported_decls);
virtual bool
DeclContextIsStructUnionOrClass (void *opaque_decl_ctx) = 0;

5
lldb/packages/Python/lldbsuite/test/lang/cpp/member-and-local-vars-with-same-name/Makefile Normal file
View File

@ -0,0 +1,5 @@
LEVEL = ../../../make
CXX_SOURCES = main.cpp
include $(LEVEL)/Makefile.rules

197
lldb/packages/Python/lldbsuite/test/lang/cpp/member-and-local-vars-with-same-name/TestMembersAndLocalsWithSameName.py Normal file
View File

@ -0,0 +1,197 @@
import lldb
from lldbsuite.test.lldbtest import *
import lldbsuite.test.lldbutil as lldbutil
class TestMembersAndLocalsWithSameName(TestBase):
mydir = TestBase.compute_mydir(__file__)
def test_when_stopped_in_method(self):
self._load_exe()
# Set breakpoints
bp1 = self.target.BreakpointCreateBySourceRegex("Break 1", self.src_file_spec)
self.assertTrue(bp1.IsValid() and bp1.GetNumLocations() >= 1, VALID_BREAKPOINT)
bp2 = self.target.BreakpointCreateBySourceRegex("Break 2", self.src_file_spec)
self.assertTrue(bp2.IsValid() and bp2.GetNumLocations() >= 1, VALID_BREAKPOINT)
bp3 = self.target.BreakpointCreateBySourceRegex("Break 3", self.src_file_spec)
self.assertTrue(bp3.IsValid() and bp3.GetNumLocations() >= 1, VALID_BREAKPOINT)
bp4 = self.target.BreakpointCreateBySourceRegex("Break 4", self.src_file_spec)
self.assertTrue(bp4.IsValid() and bp4.GetNumLocations() >= 1, VALID_BREAKPOINT)
# Launch the process
self.process = self.target.LaunchSimple(None, None, self.get_process_working_directory())
self.assertTrue(self.process.IsValid(), PROCESS_IS_VALID)
self.assertTrue(self.process.GetState() == lldb.eStateStopped, PROCESS_STOPPED)
self._test_globals()
self.process.Continue()
self.assertTrue(self.process.GetState() == lldb.eStateStopped, PROCESS_STOPPED)
thread = lldbutil.get_stopped_thread(self.process, lldb.eStopReasonBreakpoint)
self.assertTrue(thread.IsValid())
frame = thread.GetSelectedFrame()
self.assertTrue(frame.IsValid())
val = frame.EvaluateExpression("a");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 12345)
val = frame.EvaluateExpression("b");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 54321)
val = frame.EvaluateExpression("c");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 34567)
self.process.Continue()
self.assertTrue(self.process.GetState() == lldb.eStateStopped, PROCESS_STOPPED)
thread = lldbutil.get_stopped_thread(self.process, lldb.eStopReasonBreakpoint)
self.assertTrue(thread.IsValid())
frame = thread.GetSelectedFrame()
self.assertTrue(frame.IsValid())
val = frame.EvaluateExpression("a");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 10001)
val = frame.EvaluateExpression("b");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 10002)
val = frame.EvaluateExpression("c");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 10003)
self.process.Continue()
self.assertTrue(self.process.GetState() == lldb.eStateStopped, PROCESS_STOPPED)
thread = lldbutil.get_stopped_thread(self.process, lldb.eStopReasonBreakpoint)
self.assertTrue(thread.IsValid())
frame = thread.GetSelectedFrame()
self.assertTrue(frame.IsValid())
val = frame.EvaluateExpression("a");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 1)
val = frame.EvaluateExpression("b");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 2)
val = frame.EvaluateExpression("c");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 778899)
def test_when_stopped_in_function(self):
self._load_exe()
# Set breakpoints
bp1 = self.target.BreakpointCreateBySourceRegex("Break 1", self.src_file_spec)
self.assertTrue(bp1.IsValid() and bp1.GetNumLocations() >= 1, VALID_BREAKPOINT)
bp5 = self.target.BreakpointCreateBySourceRegex("Break 5", self.src_file_spec)
self.assertTrue(bp5.IsValid() and bp5.GetNumLocations() >= 1, VALID_BREAKPOINT)
bp6 = self.target.BreakpointCreateBySourceRegex("Break 6", self.src_file_spec)
self.assertTrue(bp6.IsValid() and bp6.GetNumLocations() >= 1, VALID_BREAKPOINT)
bp7 = self.target.BreakpointCreateBySourceRegex("Break 7", self.src_file_spec)
self.assertTrue(bp7.IsValid() and bp7.GetNumLocations() >= 1, VALID_BREAKPOINT)
# Launch the process
self.process = self.target.LaunchSimple(None, None, self.get_process_working_directory())
self.assertTrue(self.process.IsValid(), PROCESS_IS_VALID)
self.assertTrue(self.process.GetState() == lldb.eStateStopped, PROCESS_STOPPED)
self._test_globals()
self.process.Continue()
self.assertTrue(self.process.GetState() == lldb.eStateStopped, PROCESS_STOPPED)
thread = lldbutil.get_stopped_thread(self.process, lldb.eStopReasonBreakpoint)
self.assertTrue(thread.IsValid())
frame = thread.GetSelectedFrame()
self.assertTrue(frame.IsValid())
val = frame.EvaluateExpression("a");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 12345)
val = frame.EvaluateExpression("b");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 54321)
val = frame.EvaluateExpression("c");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 34567)
self.process.Continue()
self.assertTrue(self.process.GetState() == lldb.eStateStopped, PROCESS_STOPPED)
thread = lldbutil.get_stopped_thread(self.process, lldb.eStopReasonBreakpoint)
self.assertTrue(thread.IsValid())
frame = thread.GetSelectedFrame()
self.assertTrue(frame.IsValid())
val = frame.EvaluateExpression("a");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 10001)
val = frame.EvaluateExpression("b");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 10002)
val = frame.EvaluateExpression("c");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 10003)
self.process.Continue()
self.assertTrue(self.process.GetState() == lldb.eStateStopped, PROCESS_STOPPED)
thread = lldbutil.get_stopped_thread(self.process, lldb.eStopReasonBreakpoint)
self.assertTrue(thread.IsValid())
frame = thread.GetSelectedFrame()
self.assertTrue(frame.IsValid())
val = frame.EvaluateExpression("a");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 1)
val = frame.EvaluateExpression("b");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 2)
val = frame.EvaluateExpression("c");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 778899)
def _load_exe(self):
self.build()
cwd = os.getcwd()
src_file = os.path.join(cwd, "main.cpp")
self.src_file_spec = lldb.SBFileSpec(src_file)
self.assertTrue(self.src_file_spec.IsValid(), "breakpoint file")
# Get the path of the executable
exe_path = os.path.join(cwd, 'a.out')
# Load the executable
self.target = self.dbg.CreateTarget(exe_path)
self.assertTrue(self.target.IsValid(), VALID_TARGET)
def _test_globals(self):
thread = lldbutil.get_stopped_thread(self.process, lldb.eStopReasonBreakpoint)
self.assertTrue(thread.IsValid())
frame = thread.GetSelectedFrame()
self.assertTrue(frame.IsValid())
val = frame.EvaluateExpression("a");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 112233)
val = frame.EvaluateExpression("b");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 445566)
val = frame.EvaluateExpression("c");
self.assertTrue(val.IsValid())
self.assertEqual(val.GetValueAsUnsigned(), 778899)

73
lldb/packages/Python/lldbsuite/test/lang/cpp/member-and-local-vars-with-same-name/main.cpp Normal file
View File

@ -0,0 +1,73 @@
namespace NN
{
int a = 778899;
int b = 665544;
int c = 445566;
}
class A
{
public:
A();
int Method(int a, int b);
private:
int a, b;
};
A::A() : a(10), b(100) { }
int a = 112233;
int b = 445566;
int c = 778899;
int
A::Method(int a, int b)
{
{
int a = 12345;
int b = 54321;
int c = 34567;
this->a = a + b + this->b; // Break 2
}
{
using namespace NN;
int a = 10001;
int b = 10002;
int c = 10003;
this->a = a + b + this->b; // Break 3
}
return this->a + this->b + a + b; // Break 4
}
int
Function(int a, int b)
{
int A;
{
int a = 12345;
int b = 54321;
int c = 34567;
A = a + b + c; // Break 5
}
{
using namespace NN;
int a = 10001;
int b = 10002;
int c = 10003;
A = a + b + c; // Break 6
}
return A + a + b; // Break 7
}
int
main()
{
A obj;
return obj.Method(1, 2) + Function(1, 2); // Break 1
}

33
lldb/source/Expression/ExpressionSourceCode.cpp
View File

@ -16,7 +16,9 @@
#include "lldb/Symbol/DebugMacros.h"
#include "lldb/Symbol/Block.h"
#include "lldb/Symbol/TypeSystem.h"
#include "lldb/Symbol/VariableList.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Language.h"
#include "lldb/Target/Platform.h"
#include "lldb/Target/StackFrame.h"
#include "lldb/Target/Target.h"
@ -175,6 +177,21 @@ AddMacros(const DebugMacros *dm, CompileUnit *comp_unit, AddMacroState &state, S
}
}
static void
AddLocalVariableDecls(const lldb::VariableListSP &var_list_sp, StreamString &stream)
{
for (size_t i = 0; i < var_list_sp->GetSize(); i++)
{
lldb::VariableSP var_sp = var_list_sp->GetVariableAtIndex(i);
ConstString var_name = var_sp->GetName();
if (var_name == ConstString("this"))
continue;
stream.Printf("using $__lldb_local_vars::%s;\n", var_name.AsCString());
}
}
bool ExpressionSourceCode::GetText (std::string &text, lldb::LanguageType wrapping_language, bool const_object, bool static_method, ExecutionContext &exe_ctx) const
{
const char *target_specific_defines = "typedef signed char BOOL;\n";
@ -239,6 +256,7 @@ bool ExpressionSourceCode::GetText (std::string &text, lldb::LanguageType wrappi
}
StreamString debug_macros_stream;
StreamString lldb_local_var_decls;
if (StackFrame *frame = exe_ctx.GetFramePtr())
{
const SymbolContext &sc = frame->GetSymbolContext(
@ -253,8 +271,15 @@ bool ExpressionSourceCode::GetText (std::string &text, lldb::LanguageType wrappi
AddMacros(dm, sc.comp_unit, state, debug_macros_stream);
}
}
ConstString object_name;
if (Language::LanguageIsCPlusPlus(frame->GetLanguage()))
{
lldb::VariableListSP var_list_sp = frame->GetInScopeVariableList(false);
AddLocalVariableDecls(var_list_sp, lldb_local_var_decls);
}
}
if (m_wrap)
{
switch (wrapping_language)
@ -284,19 +309,23 @@ bool ExpressionSourceCode::GetText (std::string &text, lldb::LanguageType wrappi
wrap_stream.Printf("void \n"
"%s(void *$__lldb_arg) \n"
"{ \n"
" %s; \n"
" %s; \n"
"} \n",
m_name.c_str(),
lldb_local_var_decls.GetData(),
m_body.c_str());
break;
case lldb::eLanguageTypeC_plus_plus:
wrap_stream.Printf("void \n"
"$__lldb_class::%s(void *$__lldb_arg) %s\n"
"{ \n"
" %s; \n"
" %s; \n"
"} \n",
m_name.c_str(),
(const_object ? "const" : ""),
lldb_local_var_decls.GetData(),
m_body.c_str());
break;
case lldb::eLanguageTypeObjC:
@ -339,6 +368,6 @@ bool ExpressionSourceCode::GetText (std::string &text, lldb::LanguageType wrappi
{
text.append(m_body);
}
return true;
}

68
lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
View File

@ -57,6 +57,11 @@ using namespace lldb;
using namespace lldb_private;
using namespace clang;
namespace
{
const char *g_lldb_local_vars_namespace_cstr = "$__lldb_local_vars";
} // anonymous namespace
ClangExpressionDeclMap::ClangExpressionDeclMap (bool keep_result_in_memory,
Materializer::PersistentVariableDelegate *result_delegate,
ExecutionContext &exe_ctx) :
@ -1004,6 +1009,24 @@ ClangExpressionDeclMap::FindGlobalVariable
return VariableSP();
}
ClangASTContext *
ClangExpressionDeclMap::GetClangASTContext ()
{
StackFrame *frame = m_parser_vars->m_exe_ctx.GetFramePtr();
if (frame == nullptr)
return nullptr;
SymbolContext sym_ctx = frame->GetSymbolContext(lldb::eSymbolContextFunction|lldb::eSymbolContextBlock);
if (sym_ctx.block == nullptr)
return nullptr;
CompilerDeclContext frame_decl_context = sym_ctx.block->GetDeclContext();
if (!frame_decl_context)
return nullptr;
return llvm::dyn_cast_or_null<ClangASTContext>(frame_decl_context.GetTypeSystem());
}
// Interface for ClangASTSource
void
@ -1039,6 +1062,13 @@ ClangExpressionDeclMap::FindExternalVisibleDecls (NameSearchContext &context)
if (const NamespaceDecl *namespace_context = dyn_cast<NamespaceDecl>(context.m_decl_context))
{
if (namespace_context->getName().str() == std::string(g_lldb_local_vars_namespace_cstr))
{
CompilerDeclContext compiler_decl_ctx(GetClangASTContext(), (void*)context.m_decl_context);
FindExternalVisibleDecls(context, lldb::ModuleSP(), compiler_decl_ctx, current_id);
return;
}
ClangASTImporter::NamespaceMapSP namespace_map = m_ast_importer_sp->GetNamespaceMap(namespace_context);
if (log && log->GetVerbose())
@ -1335,6 +1365,32 @@ ClangExpressionDeclMap::FindExternalVisibleDecls (NameSearchContext &context,
return;
}
if (name == ConstString(g_lldb_local_vars_namespace_cstr))
{
CompilerDeclContext frame_decl_context = sym_ctx.block != nullptr ?
sym_ctx.block->GetDeclContext() :
CompilerDeclContext();
if (frame_decl_context)
{
ClangASTContext *ast = llvm::dyn_cast_or_null<ClangASTContext>(frame_decl_context.GetTypeSystem());
if (ast)
{
clang::NamespaceDecl *namespace_decl = ClangASTContext::GetUniqueNamespaceDeclaration(
m_ast_context, name_unique_cstr, nullptr);
if (namespace_decl)
{
context.AddNamedDecl(namespace_decl);
clang::DeclContext *clang_decl_ctx = clang::Decl::castToDeclContext(namespace_decl);
clang_decl_ctx->setHasExternalVisibleStorage(true);
}
}
}
return;
}
// any other $__lldb names should be weeded out now
if (!::strncmp(name_unique_cstr, "$__lldb", sizeof("$__lldb") - 1))
return;
@ -1403,19 +1459,23 @@ ClangExpressionDeclMap::FindExternalVisibleDecls (NameSearchContext &context,
ValueObjectSP valobj;
VariableSP var;
if (frame && !namespace_decl)
bool local_var_lookup = !namespace_decl ||
(namespace_decl.GetName() == ConstString(g_lldb_local_vars_namespace_cstr));
if (frame && local_var_lookup)
{
CompilerDeclContext compiler_decl_context = sym_ctx.block != nullptr ? sym_ctx.block->GetDeclContext() : CompilerDeclContext();
if (compiler_decl_context)
{
// Make sure that the variables are parsed so that we have the declarations
// Make sure that the variables are parsed so that we have the declarations.
VariableListSP vars = frame->GetInScopeVariableList(true);
for (size_t i = 0; i < vars->GetSize(); i++)
vars->GetVariableAtIndex(i)->GetDecl();
// Search for declarations matching the name
std::vector<CompilerDecl> found_decls = compiler_decl_context.FindDeclByName(name);
// Search for declarations matching the name. Do not include imported decls
// in the search if we are looking for decls in the artificial namespace
// $__lldb_local_vars.
std::vector<CompilerDecl> found_decls = compiler_decl_context.FindDeclByName(name, namespace_decl.IsValid());
bool variable_found = false;
for (CompilerDecl decl : found_decls)

3
lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.h
View File

@ -707,6 +707,9 @@ private:
AddThisType(NameSearchContext &context,
TypeFromUser &type,
unsigned int current_id);
ClangASTContext *
GetClangASTContext();
};
} // namespace lldb_private

19
lldb/source/Symbol/ClangASTContext.cpp
View File

@ -1885,6 +1885,17 @@ ClangASTContext::GetUniqueNamespaceDeclaration (const char *name, DeclContext *d
return namespace_decl;
}
NamespaceDecl *
ClangASTContext::GetUniqueNamespaceDeclaration (clang::ASTContext *ast,
const char *name,
clang::DeclContext *decl_ctx)
{
ClangASTContext *ast_ctx = ClangASTContext::GetASTContext(ast);
if (ast_ctx == nullptr)
return nullptr;
return ast_ctx->GetUniqueNamespaceDeclaration(name, decl_ctx);
}
clang::BlockDecl *
ClangASTContext::CreateBlockDeclaration (clang::DeclContext *ctx)
@ -9781,7 +9792,9 @@ ClangASTContext::DeclGetFunctionArgumentType (void *opaque_decl, size_t idx)
//----------------------------------------------------------------------
std::vector<CompilerDecl>
ClangASTContext::DeclContextFindDeclByName(void *opaque_decl_ctx, ConstString name)
ClangASTContext::DeclContextFindDeclByName(void *opaque_decl_ctx,
ConstString name,
const bool ignore_using_decls)
{
std::vector<CompilerDecl> found_decls;
if (opaque_decl_ctx)
@ -9805,12 +9818,16 @@ ClangASTContext::DeclContextFindDeclByName(void *opaque_decl_ctx, ConstString na
{
if (clang::UsingDirectiveDecl *ud = llvm::dyn_cast<clang::UsingDirectiveDecl>(child))
{
if (ignore_using_decls)
continue;
clang::DeclContext *from = ud->getCommonAncestor();
if (searched.find(ud->getNominatedNamespace()) == searched.end())
search_queue.insert(std::make_pair(from, ud->getNominatedNamespace()));
}
else if (clang::UsingDecl *ud = llvm::dyn_cast<clang::UsingDecl>(child))
{
if (ignore_using_decls)
continue;
for (clang::UsingShadowDecl *usd : ud->shadows())
{
clang::Decl *target = usd->getTargetDecl();

5
lldb/source/Symbol/CompilerDeclContext.cpp
View File

@ -15,10 +15,11 @@
using namespace lldb_private;
std::vector<CompilerDecl>
CompilerDeclContext::FindDeclByName (ConstString name)
CompilerDeclContext::FindDeclByName (ConstString name, const bool ignore_using_decls)
{
if (IsValid())
return m_type_system->DeclContextFindDeclByName(m_opaque_decl_ctx, name);
return m_type_system->DeclContextFindDeclByName(
m_opaque_decl_ctx, name, ignore_using_decls);
else
return std::vector<CompilerDecl>();
}

4
lldb/source/Symbol/TypeSystem.cpp
View File

@ -153,7 +153,9 @@ TypeSystem::DeclGetFunctionArgumentType (void *opaque_decl, size_t arg_idx)
std::vector<CompilerDecl>
TypeSystem::DeclContextFindDeclByName (void *opaque_decl_ctx, ConstString name)
TypeSystem::DeclContextFindDeclByName (void *opaque_decl_ctx,
ConstString name,
bool ignore_imported_decls)
{
return std::vector<CompilerDecl>();
}