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Minor readability tweaks to VFTableBuilder.cpp 

llvm-svn: 222140
This commit is contained in:
Timur Iskhodzhanov 2014-11-17 15:53:50 +00:00
parent 9a1ac6e494
commit 7081460287
1 changed files with 14 additions and 12 deletions
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26
clang/lib/AST/VTableBuilder.cpp
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@ -2831,6 +2831,7 @@ VFTableBuilder::ComputeThisOffset(FinalOverriders::OverriderInfo Overrider) {
// vtordisp // vtordisp
// FIXME: if a structor knows it belongs to MDC, why doesn't it use a vftable // FIXME: if a structor knows it belongs to MDC, why doesn't it use a vftable
// without vtordisp thunks? // without vtordisp thunks?
// FIXME: how are vtordisp handled in the presence of nooverride/final?
// //
// When foo() is called, an object with a layout of class C has a vftable // When foo() is called, an object with a layout of class C has a vftable
// referencing B::f() that assumes a B layout, so the "this" adjustments are // referencing B::f() that assumes a B layout, so the "this" adjustments are
@ -2893,9 +2894,9 @@ void VFTableBuilder::CalculateVtordispAdjustment(
// OK, now we know we need to use a vtordisp thunk. // OK, now we know we need to use a vtordisp thunk.
// The implicit vtordisp field is located right before the vbase. // The implicit vtordisp field is located right before the vbase.
CharUnits VFPtrVBaseOffset = VBaseMapEntry->second.VBaseOffset; CharUnits OffsetOfVBaseWithVFPtr = VBaseMapEntry->second.VBaseOffset;
TA.Virtual.Microsoft.VtordispOffset = TA.Virtual.Microsoft.VtordispOffset =
(VFPtrVBaseOffset - WhichVFPtr.FullOffsetInMDC).getQuantity() - 4; (OffsetOfVBaseWithVFPtr - WhichVFPtr.FullOffsetInMDC).getQuantity() - 4;
// A simple vtordisp thunk will suffice if the final overrider is defined // A simple vtordisp thunk will suffice if the final overrider is defined
// in either the most derived class or its non-virtual base. // in either the most derived class or its non-virtual base.
@ -2906,7 +2907,7 @@ void VFTableBuilder::CalculateVtordispAdjustment(
// Otherwise, we need to do use the dynamic offset of the final overrider // Otherwise, we need to do use the dynamic offset of the final overrider
// in order to get "this" adjustment right. // in order to get "this" adjustment right.
TA.Virtual.Microsoft.VBPtrOffset = TA.Virtual.Microsoft.VBPtrOffset =
(VFPtrVBaseOffset + WhichVFPtr.NonVirtualOffset - (OffsetOfVBaseWithVFPtr + WhichVFPtr.NonVirtualOffset -
MostDerivedClassLayout.getVBPtrOffset()).getQuantity(); MostDerivedClassLayout.getVBPtrOffset()).getQuantity();
TA.Virtual.Microsoft.VBOffsetOffset = TA.Virtual.Microsoft.VBOffsetOffset =
Context.getTypeSizeInChars(Context.IntTy).getQuantity() * Context.getTypeSizeInChars(Context.IntTy).getQuantity() *
@ -3001,20 +3002,21 @@ void VFTableBuilder::AddMethods(BaseSubobject Base, unsigned BaseDepth,
for (unsigned I = 0, E = VirtualMethods.size(); I != E; ++I) { for (unsigned I = 0, E = VirtualMethods.size(); I != E; ++I) {
const CXXMethodDecl *MD = VirtualMethods[I]; const CXXMethodDecl *MD = VirtualMethods[I];
FinalOverriders::OverriderInfo Overrider = FinalOverriders::OverriderInfo FinalOverrider =
Overriders.getOverrider(MD, Base.getBaseOffset()); Overriders.getOverrider(MD, Base.getBaseOffset());
const CXXMethodDecl *OverriderMD = Overrider.Method; const CXXMethodDecl *FinalOverriderMD = FinalOverrider.Method;
const CXXMethodDecl *OverriddenMD = const CXXMethodDecl *OverriddenMD =
FindNearestOverriddenMethod(MD, VisitedBases); FindNearestOverriddenMethod(MD, VisitedBases);
ThisAdjustment ThisAdjustmentOffset; ThisAdjustment ThisAdjustmentOffset;
bool ReturnAdjustingThunk = false, ForceReturnAdjustmentMangling = false; bool ReturnAdjustingThunk = false, ForceReturnAdjustmentMangling = false;
CharUnits ThisOffset = ComputeThisOffset(Overrider); CharUnits ThisOffset = ComputeThisOffset(FinalOverrider);
ThisAdjustmentOffset.NonVirtual = ThisAdjustmentOffset.NonVirtual =
(ThisOffset - WhichVFPtr.FullOffsetInMDC).getQuantity(); (ThisOffset - WhichVFPtr.FullOffsetInMDC).getQuantity();
if ((OverriddenMD || OverriderMD != MD) && if ((OverriddenMD || FinalOverriderMD != MD) &&
WhichVFPtr.getVBaseWithVPtr()) WhichVFPtr.getVBaseWithVPtr())
CalculateVtordispAdjustment(Overrider, ThisOffset, ThisAdjustmentOffset); CalculateVtordispAdjustment(FinalOverrider, ThisOffset,
ThisAdjustmentOffset);
if (OverriddenMD) { if (OverriddenMD) {
// If MD overrides anything in this vftable, we need to update the entries. // If MD overrides anything in this vftable, we need to update the entries.
@ -3056,7 +3058,7 @@ void VFTableBuilder::AddMethods(BaseSubobject Base, unsigned BaseDepth,
// Force a special name mangling for a return-adjusting thunk // Force a special name mangling for a return-adjusting thunk
// unless the method is the final overrider without this adjustment. // unless the method is the final overrider without this adjustment.
ForceReturnAdjustmentMangling = ForceReturnAdjustmentMangling =
!(MD == OverriderMD && ThisAdjustmentOffset.isEmpty()); !(MD == FinalOverriderMD && ThisAdjustmentOffset.isEmpty());
} else if (Base.getBaseOffset() != WhichVFPtr.FullOffsetInMDC || } else if (Base.getBaseOffset() != WhichVFPtr.FullOffsetInMDC ||
MD->size_overridden_methods()) { MD->size_overridden_methods()) {
// Skip methods that don't belong to the vftable of the current class, // Skip methods that don't belong to the vftable of the current class,
@ -3081,9 +3083,9 @@ void VFTableBuilder::AddMethods(BaseSubobject Base, unsigned BaseDepth,
// We don't want to do this for pure virtual member functions. // We don't want to do this for pure virtual member functions.
BaseOffset ReturnAdjustmentOffset; BaseOffset ReturnAdjustmentOffset;
ReturnAdjustment ReturnAdjustment; ReturnAdjustment ReturnAdjustment;
if (!OverriderMD->isPure()) { if (!FinalOverriderMD->isPure()) {
ReturnAdjustmentOffset = ReturnAdjustmentOffset =
ComputeReturnAdjustmentBaseOffset(Context, OverriderMD, MD); ComputeReturnAdjustmentBaseOffset(Context, FinalOverriderMD, MD);
} }
if (!ReturnAdjustmentOffset.isEmpty()) { if (!ReturnAdjustmentOffset.isEmpty()) {
ForceReturnAdjustmentMangling = true; ForceReturnAdjustmentMangling = true;
@ -3100,7 +3102,7 @@ void VFTableBuilder::AddMethods(BaseSubobject Base, unsigned BaseDepth,
} }
} }
AddMethod(OverriderMD, AddMethod(FinalOverriderMD,
ThunkInfo(ThisAdjustmentOffset, ReturnAdjustment, ThunkInfo(ThisAdjustmentOffset, ReturnAdjustment,
ForceReturnAdjustmentMangling ? MD : nullptr)); ForceReturnAdjustmentMangling ? MD : nullptr));
} }