[Lldb-commits] [lldb] [lldb/DWARF] Optimize DIEToType handling (PR #96308)
via lldb-commits
lldb-commits at lists.llvm.org
Fri Jun 21 06:46:48 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lldb
Author: Pavel Labath (labath)
<details>
<summary>Changes</summary>
- move type insertion from individual parse methods into ParseTypeFromDWARF
- optimize sentinel (TYPE_IS_BEING_PARSED) insertion to avoid double map lookup
- as this requires the map to not have nullptr values, I've replaced all `operator[]` queries with calls to `lookup`.
---
Full diff: https://github.com/llvm/llvm-project/pull/96308.diff
1 Files Affected:
- (modified) lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp (+74-104)
``````````diff
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index ae3eaf88ff4a8..52f4d765cbbd4 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -223,7 +223,6 @@ TypeSP DWARFASTParserClang::ParseTypeFromClangModule(const SymbolContext &sc,
nullptr, LLDB_INVALID_UID, Type::eEncodingInvalid,
&pcm_type_sp->GetDeclaration(), type, Type::ResolveState::Forward,
TypePayloadClang(GetOwningClangModule(die)));
- dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
clang::TagDecl *tag_decl = TypeSystemClang::GetAsTagDecl(type);
if (tag_decl) {
LinkDeclContextToDIE(tag_decl, die);
@@ -458,90 +457,78 @@ TypeSP DWARFASTParserClang::ParseTypeFromDWARF(const SymbolContext &sc,
DW_TAG_value_to_name(die.Tag()), die.Tag(), die.GetName());
}
- Type *type_ptr = dwarf->GetDIEToType().lookup(die.GetDIE());
- if (type_ptr == DIE_IS_BEING_PARSED)
- return nullptr;
- if (type_ptr)
- return type_ptr->shared_from_this();
// Set a bit that lets us know that we are currently parsing this
- dwarf->GetDIEToType()[die.GetDIE()] = DIE_IS_BEING_PARSED;
+ if (auto [it, inserted] =
+ dwarf->GetDIEToType().try_emplace(die.GetDIE(), DIE_IS_BEING_PARSED);
+ !inserted) {
+ if (it->getSecond() == nullptr || it->getSecond() == DIE_IS_BEING_PARSED)
+ return nullptr;
+ return it->getSecond()->shared_from_this();
+ }
ParsedDWARFTypeAttributes attrs(die);
+ TypeSP type_sp;
if (DWARFDIE signature_die = attrs.signature.Reference()) {
- if (TypeSP type_sp =
- ParseTypeFromDWARF(sc, signature_die, type_is_new_ptr)) {
- dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
+ type_sp = ParseTypeFromDWARF(sc, signature_die, type_is_new_ptr);
+ if (type_sp) {
if (clang::DeclContext *decl_ctx =
GetCachedClangDeclContextForDIE(signature_die))
LinkDeclContextToDIE(decl_ctx, die);
- return type_sp;
}
- return nullptr;
- }
-
- if (type_is_new_ptr)
- *type_is_new_ptr = true;
-
- const dw_tag_t tag = die.Tag();
-
- TypeSP type_sp;
-
- switch (tag) {
- case DW_TAG_typedef:
- case DW_TAG_base_type:
- case DW_TAG_pointer_type:
- case DW_TAG_reference_type:
- case DW_TAG_rvalue_reference_type:
- case DW_TAG_const_type:
- case DW_TAG_restrict_type:
- case DW_TAG_volatile_type:
- case DW_TAG_LLVM_ptrauth_type:
- case DW_TAG_atomic_type:
- case DW_TAG_unspecified_type: {
- type_sp = ParseTypeModifier(sc, die, attrs);
- break;
- }
-
- case DW_TAG_structure_type:
- case DW_TAG_union_type:
- case DW_TAG_class_type: {
- type_sp = ParseStructureLikeDIE(sc, die, attrs);
- break;
- }
+ } else {
+ if (type_is_new_ptr)
+ *type_is_new_ptr = true;
- case DW_TAG_enumeration_type: {
- type_sp = ParseEnum(sc, die, attrs);
- break;
- }
+ const dw_tag_t tag = die.Tag();
- case DW_TAG_inlined_subroutine:
- case DW_TAG_subprogram:
- case DW_TAG_subroutine_type: {
- type_sp = ParseSubroutine(die, attrs);
- break;
- }
- case DW_TAG_array_type: {
- type_sp = ParseArrayType(die, attrs);
- break;
- }
- case DW_TAG_ptr_to_member_type: {
- type_sp = ParsePointerToMemberType(die, attrs);
- break;
+ switch (tag) {
+ case DW_TAG_typedef:
+ case DW_TAG_base_type:
+ case DW_TAG_pointer_type:
+ case DW_TAG_reference_type:
+ case DW_TAG_rvalue_reference_type:
+ case DW_TAG_const_type:
+ case DW_TAG_restrict_type:
+ case DW_TAG_volatile_type:
+ case DW_TAG_LLVM_ptrauth_type:
+ case DW_TAG_atomic_type:
+ case DW_TAG_unspecified_type:
+ type_sp = ParseTypeModifier(sc, die, attrs);
+ break;
+ case DW_TAG_structure_type:
+ case DW_TAG_union_type:
+ case DW_TAG_class_type:
+ type_sp = ParseStructureLikeDIE(sc, die, attrs);
+ break;
+ case DW_TAG_enumeration_type:
+ type_sp = ParseEnum(sc, die, attrs);
+ break;
+ case DW_TAG_inlined_subroutine:
+ case DW_TAG_subprogram:
+ case DW_TAG_subroutine_type:
+ type_sp = ParseSubroutine(die, attrs);
+ break;
+ case DW_TAG_array_type:
+ type_sp = ParseArrayType(die, attrs);
+ break;
+ case DW_TAG_ptr_to_member_type:
+ type_sp = ParsePointerToMemberType(die, attrs);
+ break;
+ default:
+ dwarf->GetObjectFile()->GetModule()->ReportError(
+ "[{0:x16}]: unhandled type tag {1:x4} ({2}), "
+ "please file a bug and "
+ "attach the file at the start of this error message",
+ die.GetOffset(), tag, DW_TAG_value_to_name(tag));
+ break;
+ }
+ UpdateSymbolContextScopeForType(sc, die, type_sp);
}
- default:
- dwarf->GetObjectFile()->GetModule()->ReportError(
- "[{0:x16}]: unhandled type tag {1:x4} ({2}), "
- "please file a bug and "
- "attach the file at the start of this error message",
- die.GetOffset(), tag, DW_TAG_value_to_name(tag));
- break;
+ if (type_sp) {
+ dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
}
-
- // TODO: We should consider making the switch above exhaustive to simplify
- // control flow in ParseTypeFromDWARF. Then, we could simply replace this
- // return statement with a call to llvm_unreachable.
- return UpdateSymbolContextScopeForType(sc, die, type_sp);
+ return type_sp;
}
static std::optional<uint32_t>
@@ -830,12 +817,9 @@ DWARFASTParserClang::ParseTypeModifier(const SymbolContext &sc,
}
}
- type_sp = dwarf->MakeType(die.GetID(), attrs.name, attrs.byte_size, nullptr,
- attrs.type.Reference().GetID(), encoding_data_type,
- &attrs.decl, clang_type, resolve_state, payload);
-
- dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
- return type_sp;
+ return dwarf->MakeType(die.GetID(), attrs.name, attrs.byte_size, nullptr,
+ attrs.type.Reference().GetID(), encoding_data_type,
+ &attrs.decl, clang_type, resolve_state, payload);
}
std::string
@@ -885,13 +869,10 @@ TypeSP DWARFASTParserClang::ParseEnum(const SymbolContext &sc,
type_sp->GetID());
}
- // We found a real definition for this type elsewhere so lets use
- // it and cache the fact that we found a complete type for this
- // die
- dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
- clang::DeclContext *defn_decl_ctx =
- GetCachedClangDeclContextForDIE(dwarf->GetDIE(type_sp->GetID()));
- if (defn_decl_ctx)
+ // We found a real definition for this type elsewhere so must link its
+ // DeclContext to this die.
+ if (clang::DeclContext *defn_decl_ctx =
+ GetCachedClangDeclContextForDIE(dwarf->GetDIE(type_sp->GetID())))
LinkDeclContextToDIE(defn_decl_ctx, die);
return type_sp;
}
@@ -1052,7 +1033,7 @@ std::pair<bool, TypeSP> DWARFASTParserClang::ParseCXXMethod(
// Unfortunately classes don't like having stuff added
// to them after their definitions are complete...
- Type *type_ptr = dwarf->GetDIEToType()[die.GetDIE()];
+ Type *type_ptr = dwarf->GetDIEToType().lookup(die.GetDIE());
if (type_ptr && type_ptr != DIE_IS_BEING_PARSED)
return {true, type_ptr->shared_from_this()};
}
@@ -1164,7 +1145,7 @@ std::pair<bool, TypeSP> DWARFASTParserClang::ParseCXXMethod(
// we need to modify the dwarf->GetDIEToType() so it
// doesn't think we are trying to parse this DIE
// anymore...
- dwarf->GetDIEToType()[die.GetDIE()] = NULL;
+ dwarf->GetDIEToType().erase(die.GetDIE());
// Now we get the full type to force our class type to
// complete itself using the clang::ExternalASTSource
@@ -1174,7 +1155,7 @@ std::pair<bool, TypeSP> DWARFASTParserClang::ParseCXXMethod(
// The type for this DIE should have been filled in the
// function call above.
- Type *type_ptr = dwarf->GetDIEToType()[die.GetDIE()];
+ Type *type_ptr = dwarf->GetDIEToType().lookup(die.GetDIE());
if (type_ptr && type_ptr != DIE_IS_BEING_PARSED)
return {true, type_ptr->shared_from_this()};
@@ -1576,7 +1557,6 @@ TypeSP DWARFASTParserClang::UpdateSymbolContextScopeForType(
if (!type_sp)
return type_sp;
- SymbolFileDWARF *dwarf = die.GetDWARF();
DWARFDIE sc_parent_die = SymbolFileDWARF::GetParentSymbolContextDIE(die);
dw_tag_t sc_parent_tag = sc_parent_die.Tag();
@@ -1595,8 +1575,6 @@ TypeSP DWARFASTParserClang::UpdateSymbolContextScopeForType(
if (symbol_context_scope != nullptr)
type_sp->SetSymbolContextScope(symbol_context_scope);
-
- dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
return type_sp;
}
@@ -1691,7 +1669,6 @@ DWARFASTParserClang::ParseStructureLikeDIE(const SymbolContext &sc,
*unique_ast_entry_up)) {
type_sp = unique_ast_entry_up->m_type_sp;
if (type_sp) {
- dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
LinkDeclContextToDIE(
GetCachedClangDeclContextForDIE(unique_ast_entry_up->m_die), die);
return type_sp;
@@ -1763,11 +1740,6 @@ DWARFASTParserClang::ParseStructureLikeDIE(const SymbolContext &sc,
DW_TAG_value_to_name(tag), tag, attrs.name.GetCString(),
type_sp->GetID());
}
-
- // We found a real definition for this type elsewhere so lets use
- // it and cache the fact that we found a complete type for this
- // die
- dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
return type_sp;
}
}
@@ -1823,12 +1795,10 @@ DWARFASTParserClang::ParseStructureLikeDIE(const SymbolContext &sc,
type_sp->GetID());
}
- // We found a real definition for this type elsewhere so lets use
- // it and cache the fact that we found a complete type for this die
- dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
- clang::DeclContext *defn_decl_ctx =
- GetCachedClangDeclContextForDIE(dwarf->GetDIE(type_sp->GetID()));
- if (defn_decl_ctx)
+ // We found a real definition for this type elsewhere so must link its
+ // DeclContext to this die.
+ if (clang::DeclContext *defn_decl_ctx =
+ GetCachedClangDeclContextForDIE(dwarf->GetDIE(type_sp->GetID())))
LinkDeclContextToDIE(defn_decl_ctx, die);
return type_sp;
}
@@ -3809,7 +3779,7 @@ bool DWARFASTParserClang::CopyUniqueClassMethodTypes(
if (dst_decl_ctx)
src_dwarf_ast_parser->LinkDeclContextToDIE(dst_decl_ctx, src);
- if (Type *src_child_type = die_to_type[src.GetDIE()])
+ if (Type *src_child_type = die_to_type.lookup(src.GetDIE()))
die_to_type[dst.GetDIE()] = src_child_type;
};
``````````
</details>
https://github.com/llvm/llvm-project/pull/96308
More information about the lldb-commits
mailing list