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[DWARF5] Added support for deleted C++ special member functions. 

This patch adds support for deleted C++ special member functions in
clang and llvm. Also added Defaulted member encodings for future
support for defaulted member functions.

Patch by Sourabh Singh Tomar!

Differential Revision: https://reviews.llvm.org/D69215
This commit is contained in:
Adrian Prantl 2019-10-29 09:20:14 -07:00
parent 3260fa2cb0
commit f919be3365
9 changed files with 226 additions and 1 deletions
clang
lib/CodeGen
CGDebugInfo.cpp
test/CodeGenCXX
debug-info-deleted.cpp
llvm
docs
SourceLevelDebugging.rst
include/llvm
BinaryFormat
Dwarf.h
IR
DebugInfoFlags.defDebugInfoMetadata.h
lib
BinaryFormat
Dwarf.cpp
CodeGen/AsmPrinter
DwarfUnit.cpp
test/DebugInfo/X86
DW_AT_deleted.ll

23
clang/lib/CodeGen/CGDebugInfo.cpp
View File

@ -1607,8 +1607,31 @@ llvm::DISubprogram *CGDebugInfo::CreateCXXMemberFunction(
ContainingType = RecordTy;
}
// We're checking for deleted C++ special member functions
// [Ctors,Dtors, Copy/Move]
auto checkAttrDeleted = [&SPFlags](const auto *Method) {
if (Method->getCanonicalDecl()->isDeleted())
SPFlags |= llvm::DISubprogram::SPFlagDeleted;
};
switch (Method->getKind()) {
case Decl::CXXConstructor:
case Decl::CXXDestructor:
checkAttrDeleted(Method);
break;
case Decl::CXXMethod:
if (Method->isCopyAssignmentOperator() ||
Method->isMoveAssignmentOperator())
checkAttrDeleted(Method);
break;
default:
break;
}
if (Method->isNoReturn())
Flags |= llvm::DINode::FlagNoReturn;
if (Method->isStatic())
Flags |= llvm::DINode::FlagStaticMember;
if (Method->isImplicit())

31
clang/test/CodeGenCXX/debug-info-deleted.cpp Normal file
View File

@ -0,0 +1,31 @@
// Test for debug info for C++11 deleted member functions
//Supported: -O0, standalone DI
// RUN: %clang_cc1 -emit-llvm -triple x86_64-linux-gnu %s -o - \
// RUN: -O0 -disable-llvm-passes \
// RUN: -debug-info-kind=standalone \
// RUN: | FileCheck %s -check-prefix=ATTR
// ATTR: DISubprogram(name: "deleted", {{.*}}, flags: DIFlagPublic | DIFlagPrototyped,
// ATTR: DISubprogram(name: "deleted", {{.*}}, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted
// ATTR: DISubprogram(name: "operator=", linkageName: "_ZN7deletedaSERKS_", {{.*}}, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted
// ATTR: DISubprogram(name: "deleted", {{.*}}, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted
// ATTR: DISubprogram(name: "operator=", linkageName: "_ZN7deletedaSEOS_", {{.*}}, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted
// ATTR: DISubprogram(name: "~deleted", {{.*}}, flags: DIFlagPublic | DIFlagPrototyped,
class deleted {
public:
// Defaulted on purpose, so as to facilitate object creation
deleted() = default;
deleted(const deleted &) = delete;
deleted &operator=(const deleted &) = delete;
deleted(deleted &&) = delete;
deleted &operator=(deleted &&) = delete;
~deleted() = default;
};
void foo() {
deleted obj1;
}

33
llvm/docs/SourceLevelDebugging.rst
View File

@ -989,6 +989,39 @@ a C/C++ front-end would generate the following descriptors:
...
}
C++ specific debug information
==============================
C++ special member functions information
----------------------------------------
DWARF v5 introduces attributes defined to enhance debugging information of C++ programs. LLVM can generate (or omit) these appropriate DWARF attributes. In C++ a special member function Ctors, Dtors, Copy/Move Ctors, assignment operators can be declared with C++11 keyword deleted. This is represented in LLVM using spFlags value DISPFlagDeleted.
Given a class declaration with copy constructor declared as deleted:
.. code-block:: c
class foo {
public:
foo(const foo&) = deleted;
};
A C++ frontend would generate follwing:
.. code-block:: text
!17 = !DISubprogram(name: "foo", scope: !11, file: !1, line: 5, type: !18, scopeLine: 5, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted)
and this will produce an additional DWARF attibute as:
.. code-block:: text
DW_TAG_subprogram [7] *
DW_AT_name [DW_FORM_strx1] (indexed (00000006) string = "foo")
DW_AT_decl_line [DW_FORM_data1] (5)
...
DW_AT_deleted [DW_FORM_flag_present] (true)
Fortran specific debug information
==================================

1
llvm/include/llvm/BinaryFormat/Dwarf.h
View File

@ -458,6 +458,7 @@ StringRef AttributeEncodingString(unsigned Encoding);
StringRef DecimalSignString(unsigned Sign);
StringRef EndianityString(unsigned Endian);
StringRef AccessibilityString(unsigned Access);
StringRef DefaultedMemberString(unsigned DefaultedEncodings);
StringRef VisibilityString(unsigned Visibility);
StringRef VirtualityString(unsigned Virtuality);
StringRef LanguageString(unsigned Language);

5
llvm/include/llvm/IR/DebugInfoFlags.def
View File

@ -88,11 +88,14 @@ HANDLE_DISP_FLAG((1u << 5), Pure)
HANDLE_DISP_FLAG((1u << 6), Elemental)
HANDLE_DISP_FLAG((1u << 7), Recursive)
HANDLE_DISP_FLAG((1u << 8), MainSubprogram)
// May also utilize this Flag in future, when adding support
// for defaulted functions
HANDLE_DISP_FLAG((1u << 9), Deleted)
#ifdef DISP_FLAG_LARGEST_NEEDED
// Intended to be used with ADT/BitmaskEnum.h.
// NOTE: Always must be equal to largest flag, check this when adding new flags.
HANDLE_DISP_FLAG((1 << 8), Largest)
HANDLE_DISP_FLAG((1 << 9), Largest)
#undef DISP_FLAG_LARGEST_NEEDED
#endif

6
llvm/include/llvm/IR/DebugInfoMetadata.h
View File

@ -1759,6 +1759,12 @@ public:
bool isElemental() const { return getSPFlags() & SPFlagElemental; }
bool isRecursive() const { return getSPFlags() & SPFlagRecursive; }
/// Check if this is deleted member function.
///
/// Return true if this subprogram is a C++11 special
/// member function declared deleted.
bool isDeleted() const { return getSPFlags() & SPFlagDeleted; }
/// Check if this is reference-qualified.
///
/// Return true if this subprogram is a C++11 reference-qualified non-static

15
llvm/lib/BinaryFormat/Dwarf.cpp
View File

@ -274,6 +274,19 @@ StringRef llvm::dwarf::AccessibilityString(unsigned Access) {
return StringRef();
}
StringRef llvm::dwarf::DefaultedMemberString(unsigned DefaultedEncodings) {
switch (DefaultedEncodings) {
// Defaulted Member Encodings codes
case DW_DEFAULTED_no:
return "DW_DEFAULTED_no";
case DW_DEFAULTED_in_class:
return "DW_DEFAULTED_in_class";
case DW_DEFAULTED_out_of_class:
return "DW_DEFAULTED_out_of_class";
}
return StringRef();
}
StringRef llvm::dwarf::VisibilityString(unsigned Visibility) {
switch (Visibility) {
case DW_VIS_local:
@ -615,6 +628,8 @@ StringRef llvm::dwarf::AttributeValueString(uint16_t Attr, unsigned Val) {
return ArrayOrderString(Val);
case DW_AT_APPLE_runtime_class:
return LanguageString(Val);
case DW_AT_defaulted:
return DefaultedMemberString(Val);
}
return StringRef();

3
llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
View File

@ -1307,6 +1307,9 @@ void DwarfUnit::applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
addFlag(SPDie, dwarf::DW_AT_elemental);
if (SP->isRecursive())
addFlag(SPDie, dwarf::DW_AT_recursive);
if (DD->getDwarfVersion() >= 5 && SP->isDeleted())
addFlag(SPDie, dwarf::DW_AT_deleted);
}
void DwarfUnit::constructSubrangeDIE(DIE &Buffer, const DISubrange *SR,

110
llvm/test/DebugInfo/X86/DW_AT_deleted.ll Normal file
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@ -0,0 +1,110 @@
; RUN: llc < %s -filetype=obj -o %t
; RUN: llvm-dwarfdump -v %t | FileCheck %s
; C++ source to regenerate:
; class deleted {
; public:
; // Defaulted on purpose, so as to facilitate object creation
; deleted() = default;
;
; deleted(const deleted &) = delete;
; deleted &operator=(const deleted &) = delete;
;
; deleted(deleted &&) = delete;
; deleted &operator=(deleted &&) = delete;
;
; ~deleted() = default;
; };
;
; void foo() {
; deleted obj1;
; }
; $ clang++ -O0 -g -gdwarf-5 debug-info-deleted.cpp -c
; CHECK: .debug_abbrev contents:
; CHECK: [7] DW_TAG_subprogram DW_CHILDREN_yes
; CHECK: DW_AT_deleted DW_FORM_flag_present
; CHECK: [9] DW_TAG_subprogram DW_CHILDREN_yes
; CHECK: DW_AT_deleted DW_FORM_flag_present
; CHECK: .debug_info contents:
; CHECK: DW_TAG_subprogram [7]
; CHECK-NEXT: DW_AT_name [DW_FORM_strx1] (indexed (00000006) string = "deleted")
; CHECK: DW_AT_deleted [DW_FORM_flag_present] (true)
; CHECK: DW_TAG_subprogram [9]
; CHECK-NEXT: DW_AT_linkage_name [DW_FORM_strx1] (indexed (00000007) string = "_ZN7deletedaSERKS_")
; CHECK: DW_AT_deleted [DW_FORM_flag_present] (true)
; CHECK: DW_TAG_subprogram [7]
; CHECK-NEXT: DW_AT_name [DW_FORM_strx1] (indexed (00000006) string = "deleted")
; CHECK: DW_AT_deleted [DW_FORM_flag_present] (true)
; CHECK: DW_TAG_subprogram [9]
; CHECK-NEXT: DW_AT_linkage_name [DW_FORM_strx1] (indexed (00000009) string = "_ZN7deletedaSEOS_")
; CHECK-NEXT: DW_AT_name [DW_FORM_strx1] (indexed (00000008) string = "operator=")
; CHECK: DW_AT_deleted [DW_FORM_flag_present] (true)
; ModuleID = 'debug-info-deleted.cpp'
source_filename = "debug-info-deleted.cpp"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
%class.deleted = type { i8 }
; Function Attrs: noinline nounwind optnone uwtable
define dso_local void @_Z3foov() #0 !dbg !7 {
%1 = alloca %class.deleted, align 1
call void @llvm.dbg.declare(metadata %class.deleted* %1, metadata !10, metadata !DIExpression()), !dbg !34
ret void, !dbg !35
}
; Function Attrs: nounwind readnone speculatable willreturn
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
attributes #0 = { noinline nounwind optnone uwtable }
attributes #1 = { nounwind readnone speculatable willreturn }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4, !5}
!llvm.ident = !{!6}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project.git 715c47d5de9aa8860050992a7aaf27dca53f7f4a)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
!1 = !DIFile(filename: "debug-info-deleted.cpp", directory: "/home/sourabh/work/dwarf/c_c++/c++11", checksumkind: CSK_MD5, checksum: "49dc56907586479c64634558b060292d")
!2 = !{}
!3 = !{i32 2, !"Dwarf Version", i32 5}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = !{i32 1, !"wchar_size", i32 4}
!6 = !{!"clang version 10.0.0 (https://github.com/llvm/llvm-project.git 715c47d5de9aa8860050992a7aaf27dca53f7f4a)"}
!7 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 14, type: !8, scopeLine: 14, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
!8 = !DISubroutineType(types: !9)
!9 = !{null}
!10 = !DILocalVariable(name: "obj1", scope: !7, file: !1, line: 15, type: !11)
!11 = distinct !DICompositeType(tag: DW_TAG_class_type, name: "deleted", file: !1, line: 1, size: 8, flags: DIFlagTypePassByReference, elements: !12, identifier: "_ZTS7deleted")
!12 = !{!13, !17, !22, !26, !30, !33}
!13 = !DISubprogram(name: "deleted", scope: !11, file: !1, line: 3, type: !14, scopeLine: 3, flags: DIFlagPublic | DIFlagPrototyped, spFlags: 0)
!14 = !DISubroutineType(types: !15)
!15 = !{null, !16}
!16 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !11, size: 64, flags: DIFlagArtificial | DIFlagObjectPointer)
!17 = !DISubprogram(name: "deleted", scope: !11, file: !1, line: 5, type: !18, scopeLine: 5, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted)
!18 = !DISubroutineType(types: !19)
!19 = !{null, !16, !20}
!20 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !21, size: 64)
!21 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !11)
!22 = !DISubprogram(name: "operator=", linkageName: "_ZN7deletedaSERKS_", scope: !11, file: !1, line: 6, type: !23, scopeLine: 6, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted)
!23 = !DISubroutineType(types: !24)
!24 = !{!25, !16, !20}
!25 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !11, size: 64)
!26 = !DISubprogram(name: "deleted", scope: !11, file: !1, line: 8, type: !27, scopeLine: 8, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted)
!27 = !DISubroutineType(types: !28)
!28 = !{null, !16, !29}
!29 = !DIDerivedType(tag: DW_TAG_rvalue_reference_type, baseType: !11, size: 64)
!30 = !DISubprogram(name: "operator=", linkageName: "_ZN7deletedaSEOS_", scope: !11, file: !1, line: 9, type: !31, scopeLine: 9, flags: DIFlagPublic | DIFlagPrototyped, spFlags: DISPFlagDeleted)
!31 = !DISubroutineType(types: !32)
!32 = !{!25, !16, !29}
!33 = !DISubprogram(name: "~deleted", scope: !11, file: !1, line: 11, type: !14, scopeLine: 11, flags: DIFlagPublic | DIFlagPrototyped, spFlags: 0)
!34 = !DILocation(line: 15, column: 13, scope: !7)
!35 = !DILocation(line: 16, column: 3, scope: !7)