[Lldb-commits] [lldb] Reland "[lldb][DWARFASTParserClang] Fetch constant value from variable defintion if available" (PR #71800)
Michael Buch via lldb-commits
lldb-commits at lists.llvm.org
Sun Nov 12 22:09:32 PST 2023
https://github.com/Michael137 updated https://github.com/llvm/llvm-project/pull/71800
>From 21567b31b5f11c7ed17fc49139e58cef570c4dac Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Mon, 6 Nov 2023 11:34:09 +0000
Subject: [PATCH 1/2] Reland "[lldb][DWARFASTParserClang] Fetch constant value
from variable defintion if available"
---
.../SymbolFile/DWARF/DWARFASTParserClang.cpp | 62 ++++++++++++++++++-
.../SymbolFile/DWARF/DWARFASTParserClang.h | 11 ++++
.../SymbolFile/DWARF/SymbolFileDWARF.cpp | 7 +--
.../SymbolFile/DWARF/SymbolFileDWARF.h | 10 +--
.../SymbolFile/DWARF/SymbolFileDWARFDwo.cpp | 7 +++
.../SymbolFile/DWARF/SymbolFileDWARFDwo.h | 5 ++
.../TestConstStaticIntegralMember.py | 53 ++++++++++++++++
.../cpp/const_static_integral_member/main.cpp | 20 ++++++
8 files changed, 165 insertions(+), 10 deletions(-)
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index a70dc9832f425c6..570cd5d46952681 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -31,6 +31,7 @@
#include "lldb/Symbol/SymbolFile.h"
#include "lldb/Symbol/TypeList.h"
#include "lldb/Symbol/TypeMap.h"
+#include "lldb/Symbol/VariableList.h"
#include "lldb/Target/Language.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/Utility/Log.h"
@@ -139,6 +140,53 @@ static bool ShouldIgnoreArtificialField(llvm::StringRef FieldName) {
return FieldName.starts_with("_vptr$")
// gdb emit vtable pointer as "_vptr.classname"
|| FieldName.starts_with("_vptr.");
+
+std::optional<DWARFFormValue>
+DWARFASTParserClang::FindConstantOnVariableDefinition(DWARFDIE die) {
+ assert(die.Tag() == llvm::dwarf::DW_TAG_member);
+
+ auto *dwarf = die.GetDWARF();
+ if (!dwarf)
+ return {};
+
+ ConstString name{die.GetName()};
+ if (!name)
+ return {};
+
+ auto *CU = die.GetCU();
+ if (!CU)
+ return {};
+
+ DWARFASTParser *dwarf_ast = dwarf->GetDWARFParser(*CU);
+ auto parent_decl_ctx = dwarf_ast->GetDeclContextContainingUIDFromDWARF(die);
+
+ // Make sure we populate the GetDieToVariable cache.
+ VariableList variables;
+ dwarf->FindGlobalVariables(name, parent_decl_ctx, UINT_MAX, variables);
+
+ // The cache contains the variable definition whose DW_AT_specification
+ // points to our declaration DIE. Look up that definition using our
+ // declaration.
+ auto const &die_to_var = dwarf->GetDIEToVariable();
+ auto it = die_to_var.find(die.GetDIE());
+ if (it == die_to_var.end())
+ return {};
+
+ auto var_sp = it->getSecond();
+ assert(var_sp != nullptr);
+
+ if (!var_sp->GetLocationIsConstantValueData())
+ return {};
+
+ auto def = dwarf->GetDIE(var_sp->GetID());
+ auto def_attrs = def.GetAttributes();
+ DWARFFormValue form_value;
+ if (!def_attrs.ExtractFormValueAtIndex(
+ def_attrs.FindAttributeIndex(llvm::dwarf::DW_AT_const_value),
+ form_value))
+ return {};
+
+ return form_value;
}
TypeSP DWARFASTParserClang::ParseTypeFromClangModule(const SymbolContext &sc,
@@ -2914,9 +2962,21 @@ void DWARFASTParserClang::ParseSingleMember(
bool unused;
// TODO: Support float/double static members as well.
- if (!attrs.const_value_form || !ct.IsIntegerOrEnumerationType(unused))
+ if (!ct.IsIntegerOrEnumerationType(unused))
return;
+ // Newer versions of Clang don't emit the DW_AT_const_value
+ // on the declaration of an inline static data member. Instead
+ // it's attached to the definition DIE. If that's the case,
+ // try and fetch it.
+ if (!attrs.const_value_form) {
+ auto maybe_form_value = FindConstantOnVariableDefinition(die);
+ if (!maybe_form_value)
+ return;
+
+ attrs.const_value_form = *maybe_form_value;
+ }
+
llvm::Expected<llvm::APInt> const_value_or_err =
ExtractIntFromFormValue(ct, *attrs.const_value_form);
if (!const_value_or_err) {
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
index c381c58fba74263..21fd6f9d7980efc 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
@@ -373,6 +373,17 @@ class DWARFASTParserClang : public lldb_private::plugin::dwarf::DWARFASTParser {
lldb_private::CompilerType &class_clang_type,
const lldb::AccessType default_accesibility,
lldb_private::ClangASTImporter::LayoutInfo &layout_info);
+
+ /// Tries to find the definition DW_TAG_variable DIE of the the specified
+ /// DW_TAG_member 'die'. If such definition exists, returns the
+ /// DW_AT_const_value of that definition if available. Returns std::nullopt
+ /// otherwise.
+ ///
+ /// In newer versions of clang, DW_AT_const_value attributes are not attached
+ /// to the declaration of a inline static data-member anymore, but rather on
+ /// its definition. This function is used to locate said constant.
+ std::optional<lldb_private::plugin::dwarf::DWARFFormValue>
+ FindConstantOnVariableDefinition(lldb_private::plugin::dwarf::DWARFDIE die);
};
/// Parsed form of all attributes that are relevant for type reconstruction.
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index 5bd4665dff7da7f..4cf113d93120980 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -3564,9 +3564,8 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
}
// Prefer DW_AT_location over DW_AT_const_value. Both can be emitted e.g.
- // for static constexpr member variables -- DW_AT_const_value will be
- // present in the class declaration and DW_AT_location in the DIE defining
- // the member.
+ // for static constexpr member variables -- DW_AT_const_value and
+ // DW_AT_location will both be present in the DIE defining the member.
bool location_is_const_value_data =
const_value_form.IsValid() && !location_form.IsValid();
@@ -3648,7 +3647,7 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
// found there.
location_list.SetModule(debug_map_symfile->GetObjectFile()->GetModule());
- if (is_static_lifetime) {
+ if (is_static_lifetime && !location_is_const_value_data) {
if (is_external)
scope = eValueTypeVariableGlobal;
else
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
index 28430ccb87924b5..e6efbba7e24990a 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
@@ -343,6 +343,11 @@ class SymbolFileDWARF : public SymbolFileCommon {
return m_forward_decl_compiler_type_to_die;
}
+ typedef llvm::DenseMap<const DWARFDebugInfoEntry *, lldb::VariableSP>
+ DIEToVariableSP;
+
+ virtual DIEToVariableSP &GetDIEToVariable() { return m_die_to_variable_sp; }
+
virtual UniqueDWARFASTTypeMap &GetUniqueDWARFASTTypeMap();
bool ClassOrStructIsVirtual(const DWARFDIE &die);
@@ -362,9 +367,6 @@ class SymbolFileDWARF : public SymbolFileCommon {
Type *ResolveTypeUID(const DIERef &die_ref);
protected:
- typedef llvm::DenseMap<const DWARFDebugInfoEntry *, lldb::VariableSP>
- DIEToVariableSP;
-
SymbolFileDWARF(const SymbolFileDWARF &) = delete;
const SymbolFileDWARF &operator=(const SymbolFileDWARF &) = delete;
@@ -488,8 +490,6 @@ class SymbolFileDWARF : public SymbolFileCommon {
void UpdateExternalModuleListIfNeeded();
- virtual DIEToVariableSP &GetDIEToVariable() { return m_die_to_variable_sp; }
-
void BuildCuTranslationTable();
std::optional<uint32_t> GetDWARFUnitIndex(uint32_t cu_idx);
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
index 223af281cd57db7..ca698a84a9146da 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
@@ -142,3 +142,10 @@ SymbolFileDWARFDwo::GetDIE(const DIERef &die_ref) {
return DebugInfo().GetDIE(die_ref);
return GetBaseSymbolFile().GetDIE(die_ref);
}
+
+void SymbolFileDWARFDwo::FindGlobalVariables(
+ ConstString name, const CompilerDeclContext &parent_decl_ctx,
+ uint32_t max_matches, VariableList &variables) {
+ GetBaseSymbolFile().FindGlobalVariables(name, parent_decl_ctx, max_matches,
+ variables);
+}
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
index fa8376507d6a89b..9f5950e51b0c180 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
@@ -51,6 +51,11 @@ class SymbolFileDWARFDwo : public SymbolFileDWARF {
lldb::offset_t &offset,
std::vector<Value> &stack) const override;
+ void FindGlobalVariables(ConstString name,
+ const CompilerDeclContext &parent_decl_ctx,
+ uint32_t max_matches,
+ VariableList &variables) override;
+
protected:
DIEToTypePtr &GetDIEToType() override;
diff --git a/lldb/test/API/lang/cpp/const_static_integral_member/TestConstStaticIntegralMember.py b/lldb/test/API/lang/cpp/const_static_integral_member/TestConstStaticIntegralMember.py
index 78ea23ac8f70610..b84f376a3e4400d 100644
--- a/lldb/test/API/lang/cpp/const_static_integral_member/TestConstStaticIntegralMember.py
+++ b/lldb/test/API/lang/cpp/const_static_integral_member/TestConstStaticIntegralMember.py
@@ -114,6 +114,38 @@ def test_class_with_only_const_static(self):
self.expect_expr("ClassWithOnlyConstStatic::member", result_value="3")
+ def check_global_var(self, name: str, expect_type, expect_val):
+ var_list = self.target().FindGlobalVariables(name, lldb.UINT32_MAX)
+ self.assertEqual(len(var_list), 1)
+ varobj = var_list[0]
+ self.assertEqual(varobj.type.name, expect_type)
+ self.assertEqual(varobj.value, expect_val)
+
+ # For debug-info produced by older versions of clang, inline static data members
+ # wouldn't get indexed into the Names accelerator table preventing LLDB from finding
+ # them.
+ @expectedFailureAll(compiler=["clang"], compiler_version=["<", "18.0"])
+ def test_inline_static_members(self):
+ self.build()
+ lldbutil.run_to_source_breakpoint(
+ self, "// break here", lldb.SBFileSpec("main.cpp")
+ )
+
+ self.check_global_var("A::int_val", "const int", "1")
+ self.check_global_var("A::int_val_with_address", "const int", "2")
+ self.check_global_var("A::bool_val", "const bool", "true")
+ self.check_global_var("A::enum_val", "Enum", "enum_case2")
+ self.check_global_var("A::enum_bool_val", "EnumBool", "enum_bool_case1")
+ self.check_global_var("A::scoped_enum_val", "ScopedEnum", "scoped_enum_case2")
+
+ self.check_global_var("ClassWithOnlyConstStatic::member", "const int", "3")
+
+ self.check_global_var("ClassWithConstexprs::member", "const int", "2")
+ self.check_global_var("ClassWithConstexprs::enum_val", "Enum", "enum_case2")
+ self.check_global_var(
+ "ClassWithConstexprs::scoped_enum_val", "ScopedEnum", "scoped_enum_case2"
+ )
+
# With older versions of Clang, LLDB fails to evaluate classes with only
# constexpr members when dsymutil is enabled
@expectedFailureAll(
@@ -139,3 +171,24 @@ def test_class_with_only_constexpr_static(self):
self.expect_expr(
"ClassWithEnumAlias::enum_alias_alias", result_value="scoped_enum_case1"
)
+
+ def test_shadowed_static_inline_members(self):
+ """Tests that the expression evaluator and SBAPI can both
+ correctly determine the requested inline static variable
+ in the presence of multiple variables of the same name."""
+
+ self.build()
+ lldbutil.run_to_name_breakpoint(self, "bar")
+
+ self.check_global_var("ns::Foo::mem", "const int", "10")
+
+ self.expect_expr("mem", result_value="10")
+ self.expect_expr("Foo::mem", result_value="10")
+ self.expect_expr("ns::Foo::mem", result_value="10")
+ self.expect_expr("::Foo::mem", result_value="-29")
+
+ @expectedFailureAll(bugnumber="target var doesn't honour global namespace")
+ def test_shadowed_static_inline_members_xfail(self):
+ self.build()
+ lldbutil.run_to_name_breakpoint(self, "bar")
+ self.check_global_var("::Foo::mem", "const int", "-29")
diff --git a/lldb/test/API/lang/cpp/const_static_integral_member/main.cpp b/lldb/test/API/lang/cpp/const_static_integral_member/main.cpp
index 4275f471df6aed1..fb0b49e2d7aad7a 100644
--- a/lldb/test/API/lang/cpp/const_static_integral_member/main.cpp
+++ b/lldb/test/API/lang/cpp/const_static_integral_member/main.cpp
@@ -89,6 +89,25 @@ struct ClassWithEnumAlias {
ScopedEnum::scoped_enum_case1;
};
+namespace ns {
+struct Foo {
+ constexpr static int mem = 10;
+
+ void bar() { return; }
+};
+} // namespace ns
+
+struct Foo {
+ constexpr static int mem = -29;
+};
+
+int func() {
+ Foo f1;
+ ns::Foo f2;
+ f2.bar();
+ return ns::Foo::mem + Foo::mem;
+}
+
int main() {
A a;
@@ -124,6 +143,7 @@ int main() {
auto enum_alias_val = ClassWithEnumAlias::enum_alias;
auto enum_alias_alias_val = ClassWithEnumAlias::enum_alias_alias;
+ auto ret = func();
return 0; // break here
}
>From feba840daf34d0a8c0756d3cef34ec4585849c92 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Thu, 9 Nov 2023 21:28:32 +0000
Subject: [PATCH 2/2] fixup! don't need to change ParseVariableDIE to account
for constants anymore
---
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index 4cf113d93120980..b8b2eb58a8bd85c 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -3647,7 +3647,7 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
// found there.
location_list.SetModule(debug_map_symfile->GetObjectFile()->GetModule());
- if (is_static_lifetime && !location_is_const_value_data) {
+ if (is_static_lifetime) {
if (is_external)
scope = eValueTypeVariableGlobal;
else
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