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Refine the non-virtual this adjustment. Optimize out virtual this 

adjustments of zero.

llvm-svn: 86300
This commit is contained in:
Mike Stump 2009-11-06 23:27:42 +00:00
parent eb690feaef
commit cd6f9ed906
2 changed files with 68 additions and 54 deletions
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98
clang/lib/CodeGen/CGVtable.cpp
View File

@ -42,6 +42,8 @@ private:
llvm::DenseMap<const CXXMethodDecl *, Index_t> Index;
llvm::DenseMap<const CXXMethodDecl *, Index_t> VCall;
llvm::DenseMap<const CXXMethodDecl *, Index_t> VCallOffset;
// This is the offset to the nearest virtual base
llvm::DenseMap<const CXXMethodDecl *, Index_t> NonVirtualOffset;
llvm::DenseMap<const CXXRecordDecl *, Index_t> VBIndex;
typedef llvm::DenseMap<const CXXMethodDecl *, int> Pures_t;
@ -59,7 +61,6 @@ private:
const bool Extern;
const uint32_t LLVMPointerWidth;
Index_t extra;
int CurrentVBaseOffset;
typedef std::vector<std::pair<const CXXRecordDecl *, int64_t> > Path_t;
llvm::Constant *cxa_pure;
public:
@ -69,8 +70,7 @@ public:
: methods(meth), Class(c), BLayout(cgm.getContext().getASTRecordLayout(c)),
rtti(cgm.GenerateRtti(c)), VMContext(cgm.getModule().getContext()),
CGM(cgm), Extern(true),
LLVMPointerWidth(cgm.getContext().Target.getPointerWidth(0)),
CurrentVBaseOffset(0) {
LLVMPointerWidth(cgm.getContext().Target.getPointerWidth(0)) {
Ptr8Ty = llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext), 0);
// Calculate pointer for ___cxa_pure_virtual.
@ -191,7 +191,7 @@ public:
bool OverrideMethod(const CXXMethodDecl *MD, llvm::Constant *m,
bool MorallyVirtual, Index_t OverrideOffset,
Index_t Offset) {
Index_t Offset, int64_t CurrentVBaseOffset) {
const bool isPure = MD->isPure();
typedef CXXMethodDecl::method_iterator meth_iter;
// FIXME: Should OverrideOffset's be Offset?
@ -235,9 +235,10 @@ public:
Pures[MD] = 1;
Pures.erase(OMD);
Thunks.erase(OMD);
if (MorallyVirtual) {
if (MorallyVirtual || VCall.count(OMD)) {
Index_t &idx = VCall[OMD];
if (idx == 0) {
NonVirtualOffset[MD] = -OverrideOffset/8 + CurrentVBaseOffset/8;
VCallOffset[MD] = OverrideOffset/8;
idx = VCalls.size()+1;
VCalls.push_back(0);
@ -245,6 +246,7 @@ public:
MD->getNameAsCString(), (int)-idx-3, (int)VCalls[idx-1],
Class->getNameAsCString()));
} else {
NonVirtualOffset[MD] = NonVirtualOffset[OMD];
VCallOffset[MD] = VCallOffset[OMD];
VCalls[idx-1] = -VCallOffset[OMD] + OverrideOffset/8;
D1(printf(" vcall patch for %s at %d with delta %d most derived %s\n",
@ -252,33 +254,26 @@ public:
Class->getNameAsCString()));
}
VCall[MD] = idx;
CallOffset ThisOffset;
ThisOffset = std::make_pair(CurrentVBaseOffset/8 - Offset/8,
-((idx+extra+2)*LLVMPointerWidth/8));
int64_t O = NonVirtualOffset[MD];
int v = -((idx+extra+2)*LLVMPointerWidth/8);
// Optimize out virtual adjustments of 0.
if (VCalls[idx-1] == 0)
v = 0;
CallOffset ThisOffset = std::make_pair(O, v);
// FIXME: Do we always have to build a covariant thunk to save oret,
// which is the containing virtual base class?
if (ReturnOffset.first || ReturnOffset.second)
CovariantThunks[MD] = std::make_pair(std::make_pair(ThisOffset,
ReturnOffset),
oret);
else if (!isPure)
else if (!isPure && (ThisOffset.first || ThisOffset.second))
Thunks[MD] = ThisOffset;
return true;
}
// FIXME: finish off
int64_t O = VCallOffset[OMD] - OverrideOffset/8;
// int64_t O = CurrentVBaseOffset/8 - OverrideOffset/8;
if (VCall.count(OMD)) {
VCallOffset[MD] = VCallOffset[OMD];
Index_t idx = VCall[OMD];
VCalls[idx-1] = -VCallOffset[OMD] + OverrideOffset/8;
D1(printf(" vcall patch for %s at %d with delta %d most derived %s\n",
MD->getNameAsCString(), (int)-idx-3, (int)VCalls[idx-1],
Class->getNameAsCString()));
VCall[MD] = idx;
}
if (O || ReturnOffset.first || ReturnOffset.second) {
CallOffset ThisOffset = std::make_pair(O, 0);
@ -343,7 +338,8 @@ public:
return wrap(CGM.GetAddrOfFunction(MD, Ty));
}
void OverrideMethods(Path_t *Path, bool MorallyVirtual, int64_t Offset) {
void OverrideMethods(Path_t *Path, bool MorallyVirtual, int64_t Offset,
int64_t CurrentVBaseOffset) {
for (Path_t::reverse_iterator i = Path->rbegin(),
e = Path->rend(); i != e; ++i) {
const CXXRecordDecl *RD = i->first;
@ -355,17 +351,19 @@ public:
const CXXMethodDecl *MD = *mi;
llvm::Constant *m = WrapAddrOf(MD);
OverrideMethod(MD, m, MorallyVirtual, OverrideOffset, Offset);
OverrideMethod(MD, m, MorallyVirtual, OverrideOffset, Offset,
CurrentVBaseOffset);
}
}
}
void AddMethod(const CXXMethodDecl *MD, bool MorallyVirtual, Index_t Offset,
bool ForVirtualBase) {
bool ForVirtualBase, int64_t CurrentVBaseOffset) {
llvm::Constant *m = WrapAddrOf(MD);
// If we can find a previously allocated slot for this, reuse it.
if (OverrideMethod(MD, m, MorallyVirtual, Offset, Offset))
if (OverrideMethod(MD, m, MorallyVirtual, Offset, Offset,
CurrentVBaseOffset))
return;
// else allocate a new slot.
@ -379,6 +377,7 @@ public:
Index_t &idx = VCall[MD];
// Allocate the first one, after that, we reuse the previous one.
if (idx == 0) {
NonVirtualOffset[MD] = CurrentVBaseOffset/8 - Offset/8;
idx = VCalls.size()+1;
VCalls.push_back(0);
D1(printf(" vcall for %s at %d with delta %d\n",
@ -388,17 +387,20 @@ public:
}
void AddMethods(const CXXRecordDecl *RD, bool MorallyVirtual,
Index_t Offset, bool RDisVirtualBase) {
Index_t Offset, bool RDisVirtualBase,
int64_t CurrentVBaseOffset) {
for (method_iter mi = RD->method_begin(), me = RD->method_end(); mi != me;
++mi)
if (mi->isVirtual())
AddMethod(*mi, MorallyVirtual, Offset, RDisVirtualBase);
AddMethod(*mi, MorallyVirtual, Offset, RDisVirtualBase,
CurrentVBaseOffset);
}
void NonVirtualBases(const CXXRecordDecl *RD, const ASTRecordLayout &Layout,
const CXXRecordDecl *PrimaryBase,
bool PrimaryBaseWasVirtual, bool MorallyVirtual,
int64_t Offset, Path_t *Path) {
int64_t Offset, int64_t CurrentVBaseOffset,
Path_t *Path) {
Path->push_back(std::make_pair(RD, Offset));
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
@ -409,8 +411,8 @@ public:
if (Base != PrimaryBase || PrimaryBaseWasVirtual) {
uint64_t o = Offset + Layout.getBaseClassOffset(Base);
StartNewTable();
CurrentVBaseOffset = Offset;
GenerateVtableForBase(Base, MorallyVirtual, o, false, Path);
GenerateVtableForBase(Base, MorallyVirtual, o, false,
CurrentVBaseOffset, Path);
}
}
Path->pop_back();
@ -436,6 +438,7 @@ public:
Index_t end(const CXXRecordDecl *RD, const ASTRecordLayout &Layout,
const CXXRecordDecl *PrimaryBase, bool PrimaryBaseWasVirtual,
bool MorallyVirtual, int64_t Offset, bool ForVirtualBase,
int64_t CurrentVBaseOffset,
Path_t *Path) {
bool alloc = false;
if (Path == 0) {
@ -464,7 +467,7 @@ public:
// and then the non-virtual bases.
NonVirtualBases(RD, Layout, PrimaryBase, PrimaryBaseWasVirtual,
MorallyVirtual, Offset, Path);
MorallyVirtual, Offset, CurrentVBaseOffset, Path);
if (ForVirtualBase) {
insertVCalls(VCallInsertionPoint);
@ -479,7 +482,7 @@ public:
void Primaries(const CXXRecordDecl *RD, bool MorallyVirtual, int64_t Offset,
bool updateVBIndex, Index_t current_vbindex,
bool RDisVirtualBase) {
bool RDisVirtualBase, int64_t CurrentVBaseOffset) {
if (!RD->isDynamicClass())
return;
@ -492,21 +495,27 @@ public:
D1(printf(" doing primaries for %s most derived %s\n",
RD->getNameAsCString(), Class->getNameAsCString()));
int BaseCurrentVBaseOffset = CurrentVBaseOffset;
if (PrimaryBaseWasVirtual)
BaseCurrentVBaseOffset = BLayout.getVBaseClassOffset(PrimaryBase);
if (!PrimaryBaseWasVirtual)
Primaries(PrimaryBase, PrimaryBaseWasVirtual|MorallyVirtual, Offset,
updateVBIndex, current_vbindex, PrimaryBaseWasVirtual);
updateVBIndex, current_vbindex, PrimaryBaseWasVirtual,
BaseCurrentVBaseOffset);
}
D1(printf(" doing vcall entries for %s most derived %s\n",
RD->getNameAsCString(), Class->getNameAsCString()));
// And add the virtuals for the class to the primary vtable.
AddMethods(RD, MorallyVirtual, Offset, RDisVirtualBase);
AddMethods(RD, MorallyVirtual, Offset, RDisVirtualBase, CurrentVBaseOffset);
}
void VBPrimaries(const CXXRecordDecl *RD, bool MorallyVirtual, int64_t Offset,
bool updateVBIndex, Index_t current_vbindex,
bool RDisVirtualBase, bool bottom=false) {
bool RDisVirtualBase, int64_t CurrentVBaseOffset,
bool bottom=false) {
if (!RD->isDynamicClass())
return;
@ -516,14 +525,18 @@ public:
// vtables are composed from the chain of primaries.
if (PrimaryBase) {
if (PrimaryBaseWasVirtual)
int BaseCurrentVBaseOffset = CurrentVBaseOffset;
if (PrimaryBaseWasVirtual) {
IndirectPrimary.insert(PrimaryBase);
BaseCurrentVBaseOffset = BLayout.getVBaseClassOffset(PrimaryBase);
}
D1(printf(" doing primaries for %s most derived %s\n",
RD->getNameAsCString(), Class->getNameAsCString()));
VBPrimaries(PrimaryBase, PrimaryBaseWasVirtual|MorallyVirtual, Offset,
updateVBIndex, current_vbindex, PrimaryBaseWasVirtual);
updateVBIndex, current_vbindex, PrimaryBaseWasVirtual,
BaseCurrentVBaseOffset);
}
D1(printf(" doing vbase entries for %s most derived %s\n",
@ -532,13 +545,14 @@ public:
if (RDisVirtualBase || bottom) {
Primaries(RD, MorallyVirtual, Offset, updateVBIndex, current_vbindex,
RDisVirtualBase);
RDisVirtualBase, CurrentVBaseOffset);
}
}
int64_t GenerateVtableForBase(const CXXRecordDecl *RD,
bool MorallyVirtual = false, int64_t Offset = 0,
bool ForVirtualBase = false,
int CurrentVBaseOffset = 0,
Path_t *Path = 0) {
if (!RD->isDynamicClass())
return 0;
@ -555,13 +569,13 @@ public:
extra = VCalls.size();
VBPrimaries(RD, MorallyVirtual, Offset, !ForVirtualBase, 0, ForVirtualBase,
true);
CurrentVBaseOffset, true);
if (Path)
OverrideMethods(Path, MorallyVirtual, Offset);
OverrideMethods(Path, MorallyVirtual, Offset, CurrentVBaseOffset);
return end(RD, Layout, PrimaryBase, PrimaryBaseWasVirtual, MorallyVirtual,
Offset, ForVirtualBase, Path);
Offset, ForVirtualBase, CurrentVBaseOffset, Path);
}
void GenerateVtableForVBases(const CXXRecordDecl *RD,
@ -585,16 +599,16 @@ public:
StartNewTable();
VCall.clear();
int64_t BaseOffset = BLayout.getVBaseClassOffset(Base);
CurrentVBaseOffset = BaseOffset;
int64_t CurrentVBaseOffset = BaseOffset;
D1(printf("vtable %s virtual base %s\n",
Class->getNameAsCString(), Base->getNameAsCString()));
GenerateVtableForBase(Base, true, BaseOffset, true, Path);
GenerateVtableForBase(Base, true, BaseOffset, true, CurrentVBaseOffset,
Path);
}
int64_t BaseOffset = Offset;
if (i->isVirtual())
BaseOffset = BLayout.getVBaseClassOffset(Base);
if (Base->getNumVBases()) {
CurrentVBaseOffset = BaseOffset;
GenerateVtableForVBases(Base, BaseOffset, Path);
}
}

24
clang/test/CodeGenCXX/virt.cpp
View File

@ -667,7 +667,7 @@ void test16_D::bar() { }
// CHECK-LP64-NEXT: .space 8
// CHECK-LP64-NEXT: .space 8
// CHECK-LP64: .quad 18446744073709551600
// CHECK-LP64: .quad 18446744073709551584
// CHECK-LP64-NEXT: .quad 18446744073709551584
// CHECK-LP64-NEXT: .space 8
// CHECK-LP64-NEXT: .space 8
// CHECK-LP64-NEXT: .quad 18446744073709551584
@ -872,16 +872,16 @@ struct test19_D : virtual test19_B4 {
// CHECK-LP64-NEXT: .space 8
// CHECK-LP64-NEXT: .space 8
// CHECK-LP64-NEXT: .quad __ZTI8test19_D
// CHECK-LP64-NEXT .quad __ZN9test19_B13fB1Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B26foB1B2Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B36foB1B3Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B46foB1B4Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B23fB2Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B36foB2B3Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B46foB2B4Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B33fB3Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B46foB3B4Ev
// CHECK-LP64-NEXT .quad __ZN9test19_B43fB4Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B13fB1Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B26foB1B2Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B36foB1B3Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B46foB1B4Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B23fB2Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B36foB2B3Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B46foB2B4Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B33fB3Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B46foB3B4Ev
// CHECK-LP64-NEXT: .quad __ZN9test19_B43fB4Ev
class test20_V {
@ -936,7 +936,7 @@ class test21_D : public test21_B, public test21_B1 {
// CHECK-LP64-NEXT: .quad 18446744073709551608
// CHECK-LP64-NEXT: .quad 18446744073709551608
// CHECK-LP64-NEXT: .quad __ZTI8test21_D
// CHECK-LP64-NEXT .quad __ZTv0_n24_N8test21_D3fooEv
// CHECK-LP64-NEXT: .quad __ZTv0_n24_N8test21_D3fooEv