rnk created this revision.
rnk added reviewers: amccarth, aprantl, dblaikie, dexonsmith.
rnk added a subscriber: cfe-commits.
rnk added a dependency: D22884: [codeview] Emit vftable records.
MSVC emits codeview records describing all the methods contained in a
vftable. This is observable in windbg with 'dt -v'.
Depends on D22884
https://reviews.llvm.org/D22920
Files:
include/clang/AST/VTableBuilder.h
lib/AST/VTableBuilder.cpp
lib/CodeGen/CGDebugInfo.cpp
lib/CodeGen/CGDebugInfo.h
test/CodeGenCXX/debug-info-ms-abi.cpp
test/CodeGenCXX/debug-info-ms-vftables.cpp
Index: test/CodeGenCXX/debug-info-ms-vftables.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/debug-info-ms-vftables.cpp
@@ -0,0 +1,57 @@
+// RUN: %clang_cc1 %s -triple=i686-pc-windows-msvc -debug-info-kind=limited -gcodeview -emit-llvm -o - | FileCheck %s
+
+namespace diamond {
+struct A { virtual void f(); };
+struct B : virtual A { virtual void g(); };
+struct C : virtual A { virtual void h(); };
+struct D : B, C { virtual void j(); };
+D d;
+}
+
+// CHECK: distinct !DICompositeType(tag: DW_TAG_structure_type, name: "D",
+// CHECK-SAME: elements: ![[elements:[0-9]+]],
+// CHECK-SAME: identifier: ".?AUD@diamond@@")
+
+// CHECK: ![[elements]] = !{!{{[0-9]+}}, !{{[0-9]+}}, ![[vt_D_B:[0-9]+]], ![[vt_D_A:[0-9]+]], ![[vt_D_C:[0-9]+]], !{{[0-9]+}}}
+
+// CHECK: ![[vt_D_B]] = !DIDerivedType(tag: DW_TAG_LLVM_msvftable, name: "??_7D@diamond@@6BB@1@@",
+// CHECK: ![[vt_D_A]] = !DIDerivedType(tag: DW_TAG_LLVM_msvftable, name: "??_7D@diamond@@6BA@1@@",
+// CHECK: ![[vt_D_C]] = !DIDerivedType(tag: DW_TAG_LLVM_msvftable, name: "??_7D@diamond@@6BC@1@@",
+
+// This test tries to exercise all four of the possible MS ABI manglings for
+// C++ virtual methods:
+// - normal methods
+// - virtual dtors
+// - virtual dtor thunks
+// - virtual method thunks
+namespace thunks {
+struct A {
+ virtual ~A();
+ virtual void f();
+};
+struct B {
+ virtual ~B();
+ virtual void f();
+};
+struct C : A, B {
+ virtual ~C();
+ virtual void f();
+};
+C c;
+}
+
+// CHECK: ![[C_thunks:[0-9]+]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "C",
+// CHECK-SAME: elements: ![[elements:[0-9]+]],
+// CHECK-SAME: identifier: ".?AUC@thunks@@")
+
+// CHECK: ![[elements]] = !{!{{[0-9]+}}, !{{[0-9]+}}, ![[vt_C_A:[0-9]+]], ![[vt_C_B:[0-9]+]], !{{[0-9]+}}, !{{[0-9]+}}}
+
+// CHECK: ![[vt_C_A]] = !DIDerivedType(tag: DW_TAG_LLVM_msvftable, name: "??_7C@thunks@@6BA@1@@",
+// CHECK-SAME: extraData: ![[vt_C_A_methods:[0-9]+]])
+
+// CHECK: ![[vt_C_A_methods]] = !{!"??_GC@thunks@@UAEPAXI@Z", !"?f@C@thunks@@UAEXXZ"}
+
+// CHECK: ![[vt_C_B]] = !DIDerivedType(tag: DW_TAG_LLVM_msvftable, name: "??_7C@thunks@@6BB@1@@",
+// CHECK-SAME: extraData: ![[vt_C_B_methods:[0-9]+]])
+
+// CHECK: ![[vt_C_B_methods]] = !{!"??_EC@thunks@@W3AEPAXI@Z", !"?f@C@thunks@@W3AEXXZ"}
Index: test/CodeGenCXX/debug-info-ms-abi.cpp
===================================================================
--- test/CodeGenCXX/debug-info-ms-abi.cpp
+++ test/CodeGenCXX/debug-info-ms-abi.cpp
@@ -15,7 +15,11 @@
// CHECK-SAME: elements: ![[elements:[0-9]+]]
// CHECK-SAME: identifier: ".?AUFoo@@"
-// CHECK: ![[elements]] = !{![[vptr:[0-9]+]], ![[Nested:[0-9]+]], ![[f:[0-9]+]], ![[g:[0-9]+]], ![[h:[0-9]+]]}
+// CHECK: ![[elements]] = !{![[vftable:[0-9]+]], ![[vptr:[0-9]+]], ![[Nested:[0-9]+]], ![[f:[0-9]+]], ![[g:[0-9]+]], ![[h:[0-9]+]]}
+
+// CHECK: ![[vftable]] = !DIDerivedType(tag: DW_TAG_LLVM_msvftable, name: "??_7Foo@@6B@", scope: ![[Foo]], baseType: null, extraData: ![[methodlist:[0-9]+]])
+
+// CHECK: ![[methodlist]] = !{!"?f@Foo@@UAEXXZ", !"?g@Foo@@UAEXXZ", !"?h@Foo@@UAEXXZ"}
// CHECK: ![[Nested]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Nested",
// CHECK-SAME: identifier: ".?AUNested@Foo@@"
Index: lib/CodeGen/CGDebugInfo.h
===================================================================
--- lib/CodeGen/CGDebugInfo.h
+++ lib/CodeGen/CGDebugInfo.h
@@ -22,6 +22,7 @@
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/TinyPtrVector.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/ValueHandle.h"
@@ -40,6 +41,7 @@
class ObjCIvarDecl;
class UsingDecl;
class VarDecl;
+struct VPtrInfo;
namespace CodeGen {
class CodeGenModule;
@@ -128,6 +130,7 @@
NamespaceAliasCache;
llvm::DenseMap<const Decl *, llvm::TypedTrackingMDRef<llvm::DIDerivedType>>
StaticDataMemberCache;
+ llvm::DenseMap<const VPtrInfo *, llvm::TrackingMDRef> MSVFTableCache;
/// Helper functions for getOrCreateType.
/// @{
@@ -263,7 +266,13 @@
/// If the C++ class has vtable info then insert appropriate debug
/// info entry in EltTys vector.
void CollectVTableInfo(const CXXRecordDecl *Decl, llvm::DIFile *F,
- SmallVectorImpl<llvm::Metadata *> &EltTys);
+ SmallVectorImpl<llvm::Metadata *> &EltTys,
+ llvm::DIType *RecordTy);
+
+ /// Get the DW_TAG_LLVM_msvftable type for this vptr.
+ llvm::DIType *getMSVFTableType(const VPtrInfo *VPI, const CXXRecordDecl *RD,
+ llvm::DIType *RecordTy);
+
/// @}
/// Create a new lexical block node and push it on the stack.
Index: lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- lib/CodeGen/CGDebugInfo.cpp
+++ lib/CodeGen/CGDebugInfo.cpp
@@ -1546,9 +1546,19 @@
}
void CGDebugInfo::CollectVTableInfo(const CXXRecordDecl *RD, llvm::DIFile *Unit,
- SmallVectorImpl<llvm::Metadata *> &EltTys) {
+ SmallVectorImpl<llvm::Metadata *> &EltTys,
+ llvm::DIType *RecordTy) {
const ASTRecordLayout &RL = CGM.getContext().getASTRecordLayout(RD);
+ // Emit information about MS ABI vftables, primarily for the benefit of
+ // codeview.
+ if (CGM.getTarget().getCXXABI().isMicrosoft() && RD->isDynamicClass()) {
+ const VPtrInfoVector &VFPtrs =
+ CGM.getMicrosoftVTableContext().getVFPtrOffsets(RD);
+ for (const VPtrInfo *VPI : VFPtrs)
+ EltTys.push_back(getMSVFTableType(VPI, RD, RecordTy));
+ }
+
// If there is a primary base then it will hold vtable info.
if (RL.getPrimaryBase())
return;
@@ -1564,6 +1574,88 @@
EltTys.push_back(VPTR);
}
+llvm::DIType *CGDebugInfo::getMSVFTableType(const VPtrInfo *VPI,
+ const CXXRecordDecl *RD,
+ llvm::DIType *RecordTy) {
+ assert(CGM.getTarget().getCXXABI().isMicrosoft());
+
+ // Check the cache to see if we've built vftable info already.
+ auto I = MSVFTableCache.find(VPI);
+ if (I != MSVFTableCache.end())
+ return cast<llvm::DIType>(I->second.get());
+
+ // Get the name of the vftable and it's offset.
+ auto &Mangler =
+ cast<MicrosoftMangleContext>(CGM.getCXXABI().getMangleContext());
+ SmallString<256> VFTableName;
+ llvm::raw_svector_ostream VFTableNameOS(VFTableName);
+ Mangler.mangleCXXVFTable(RD, VPI->MangledPath, VFTableNameOS);
+ uint64_t VFPtrOffsetInBits = CGM.getContext().toBits(VPI->FullOffsetInMDC);
+
+ // Get the overridden vftable type.
+ llvm::DIType *OverriddenVFTable = nullptr;
+ if (VPI->OverriddenVPtr) {
+ const CXXRecordDecl *Base = VPI->DirectBase;
+ llvm::DIType *BaseTy = getOrCreateRecordType(
+ CGM.getContext().getRecordType(Base), Base->getLocation());
+ OverriddenVFTable = getMSVFTableType(VPI->OverriddenVPtr, Base, BaseTy);
+ }
+
+ // Compute the mangled names used to fill out the vftable. Keep in sync with
+ // CodeGenVTables::CreateVTableInitializer.
+ const VTableLayout &VL = CGM.getMicrosoftVTableContext().getVFTableLayout(
+ RD, VPI->FullOffsetInMDC);
+ const VTableComponent *VComponents = VL.vtable_component_begin();
+ unsigned NumComponents = VL.getNumVTableComponents();
+ const auto *VTableThunks = VL.vtable_thunk_begin();
+ unsigned NumVTableThunks = VL.getNumVTableThunks();
+ unsigned NextVTableThunkIndex = 0;
+ SmallVector<llvm::Metadata *, 4> MethodNames;
+ for (unsigned I = 0; I < NumComponents; I++) {
+ const VTableComponent &VC = VComponents[I];
+ // Skip RTTI and other Itanium stuff.
+ if (!VC.isFunctionPointerKind())
+ continue;
+
+ const CXXMethodDecl *MD = VC.getFunctionDecl();
+ SmallString<128> MethodName;
+ if (MD->isPure()) {
+ MethodName = CGM.getCXXABI().GetPureVirtualCallName();
+ } else if (MD->isDeleted()) {
+ MethodName = CGM.getCXXABI().GetDeletedVirtualCallName();
+ } else {
+ // Figure out if this is a thunk vtable slot.
+ llvm::raw_svector_ostream MethodNameOS(MethodName);
+ if (NextVTableThunkIndex < NumVTableThunks &&
+ VTableThunks[NextVTableThunkIndex].first == I) {
+ const ThunkInfo &Thunk = VTableThunks[NextVTableThunkIndex].second;
+ NextVTableThunkIndex++;
+ if (VC.isDestructorKind())
+ Mangler.mangleCXXDtorThunk(VC.getDestructorDecl(), Dtor_Deleting,
+ Thunk.This, MethodNameOS);
+ else
+ Mangler.mangleThunk(MD, Thunk, MethodNameOS);
+ } else {
+ if (VC.isDestructorKind())
+ Mangler.mangleCXXDtor(VC.getDestructorDecl(), Dtor_Deleting,
+ MethodNameOS);
+ else
+ Mangler.mangleName(MD, MethodNameOS);
+ }
+ }
+ MethodNames.push_back(
+ llvm::MDString::get(CGM.getLLVMContext(),
+ llvm::GlobalValue::getRealLinkageName(MethodName)));
+ }
+
+ llvm::DIType *VFTy = DBuilder.createMSVFTable(
+ RecordTy, llvm::GlobalValue::getRealLinkageName(VFTableName),
+ VFPtrOffsetInBits, OverriddenVFTable,
+ llvm::MDTuple::get(CGM.getLLVMContext(), MethodNames), 0);
+ MSVFTableCache[VPI].reset(VFTy);
+ return VFTy;
+}
+
llvm::DIType *CGDebugInfo::getOrCreateRecordType(QualType RTy,
SourceLocation Loc) {
assert(DebugKind >= codegenoptions::LimitedDebugInfo);
@@ -1747,7 +1839,7 @@
const auto *CXXDecl = dyn_cast<CXXRecordDecl>(RD);
if (CXXDecl) {
CollectCXXBases(CXXDecl, DefUnit, EltTys, FwdDecl);
- CollectVTableInfo(CXXDecl, DefUnit, EltTys);
+ CollectVTableInfo(CXXDecl, DefUnit, EltTys, FwdDecl);
}
// Collect data fields (including static variables and any initializers).
Index: lib/AST/VTableBuilder.cpp
===================================================================
--- lib/AST/VTableBuilder.cpp
+++ lib/AST/VTableBuilder.cpp
@@ -3303,6 +3303,10 @@
// Copy the path and adjust it as necessary.
VPtrInfo *P = new VPtrInfo(*BaseInfo);
+ // Remember the vptr we overrode.
+ P->OverriddenVPtr = BaseInfo;
+ P->DirectBase = Base;
+
// We mangle Base into the path if the path would've been ambiguous and it
// wasn't already extended with Base.
if (P->MangledPath.empty() || P->MangledPath.back() != Base)
Index: include/clang/AST/VTableBuilder.h
===================================================================
--- include/clang/AST/VTableBuilder.h
+++ include/clang/AST/VTableBuilder.h
@@ -409,6 +409,13 @@
/// methods or virtual bases.
const CXXRecordDecl *IntroducingObject;
+ /// Link to the vptr we are overriding from our base, or null the vptr was
+ /// introduced in this class.
+ const VPtrInfo *OverriddenVPtr = nullptr;
+
+ /// The direct base that we got this vptr from.
+ const CXXRecordDecl *DirectBase = nullptr;
+
/// IntroducingObject is at this offset from its containing complete object or
/// virtual base.
CharUnits NonVirtualOffset;
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