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Add basic support for simple non-virtual 'this' pointer adjustments. 

llvm-svn: 96136
This commit is contained in:
Anders Carlsson 2010-02-13 23:40:17 +00:00
parent 0daaf13b97
commit d3adb0ced9
2 changed files with 125 additions and 14 deletions
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90
clang/lib/CodeGen/CGVtable.cpp
View File

@ -156,11 +156,22 @@ public:
return OverridersMap.lookup(std::make_pair(Base, MD));
}
/// getReturnAdjustmentOffset - Get the return adjustment offset for the
/// method decl in the given base subobject. Returns an empty base offset if
/// no adjustment is needed.
BaseOffset getReturnAdjustmentOffset(BaseSubobject Base,
const CXXMethodDecl *MD) const {
return ReturnAdjustments.lookup(std::make_pair(Base, MD));
}
/// getThisAdjustmentOffset - Get the 'this' pointer adjustment offset for the
/// method decl in the given base subobject. Returns an empty base offset if
/// no adjustment is needed.
BaseOffset getThisAdjustmentOffset(BaseSubobject Base,
const CXXMethodDecl *MD) const {
return ThisAdjustments.lookup(std::make_pair(Base, MD));
}
/// dump - dump the final overriders.
void dump() const {
dump(llvm::errs(), BaseSubobject(MostDerivedClass, 0));
@ -691,7 +702,7 @@ private:
/// AddressPoints - Address points for the vtable being built.
CGVtableInfo::AddressPointsMapTy AddressPoints;
/// ReturnAdjustment - A return adjustment thunk.
/// ReturnAdjustment - A return adjustment.
struct ReturnAdjustment {
/// NonVirtual - The non-virtual adjustment from the derived object to its
/// nearest virtual base.
@ -710,13 +721,35 @@ private:
llvm::SmallVector<std::pair<uint64_t, ReturnAdjustment>, 16>
ReturnAdjustments;
/// ThisAdjustment - A 'this' pointer adjustment thunk.
struct ThisAdjustment {
/// NonVirtual - The non-virtual adjustment from the derived object to its
/// nearest virtual base.
int64_t NonVirtual;
/// FIXME: Add VCallOffsetOffset here.
ThisAdjustment() : NonVirtual(0) { }
bool isEmpty() const { return !NonVirtual; }
};
/// ThisAdjustments - The 'this' pointer adjustments needed in this vtable.
llvm::SmallVector<std::pair<uint64_t, ThisAdjustment>, 16>
ThisAdjustments;
/// ComputeReturnAdjustment - Compute the return adjustment given a return
/// adjustment base offset.
ReturnAdjustment ComputeReturnAdjustment(FinalOverriders::BaseOffset Offset);
/// ComputeThisAdjustment - Compute the 'this' pointer adjustment given a
/// 'this' pointer adjustment base offset.
ThisAdjustment ComputeThisAdjustment(FinalOverriders::BaseOffset Offset);
/// AddMethod - Add a single virtual member function to the vtable
/// components vector.
void AddMethod(const CXXMethodDecl *MD, ReturnAdjustment ReturnAdjustment);
void AddMethod(const CXXMethodDecl *MD, ReturnAdjustment ReturnAdjustment,
ThisAdjustment ThisAdjustment);
/// AddMethods - Add the methods of this base subobject and all its
/// primary bases to the vtable components vector.
@ -779,12 +812,33 @@ VtableBuilder::ComputeReturnAdjustment(FinalOverriders::BaseOffset Offset) {
return Adjustment;
}
VtableBuilder::ThisAdjustment
VtableBuilder::ComputeThisAdjustment(FinalOverriders::BaseOffset Offset) {
ThisAdjustment Adjustment;
if (!Offset.isEmpty()) {
assert(!Offset.VirtualBase && "FIXME: Handle virtual bases!");
Adjustment.NonVirtual = Offset.NonVirtualOffset;
}
return Adjustment;
}
void
VtableBuilder::AddMethod(const CXXMethodDecl *MD,
ReturnAdjustment ReturnAdjustment) {
ReturnAdjustment ReturnAdjustment,
ThisAdjustment ThisAdjustment) {
if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
assert(ReturnAdjustment.isEmpty() &&
"Destructor can't have return adjustment!");
// Add the 'this' pointer adjustments if necessary.
if (!ThisAdjustment.isEmpty()) {
ThisAdjustments.push_back(std::make_pair(Components.size(),
ThisAdjustment));
ThisAdjustments.push_back(std::make_pair(Components.size() + 1,
ThisAdjustment));
}
// Add both the complete destructor and the deleting destructor.
Components.push_back(VtableComponent::MakeCompleteDtor(DD));
Components.push_back(VtableComponent::MakeDeletingDtor(DD));
@ -794,6 +848,11 @@ VtableBuilder::AddMethod(const CXXMethodDecl *MD,
ReturnAdjustments.push_back(std::make_pair(Components.size(),
ReturnAdjustment));
// Add the 'this' pointer adjustment if necessary.
if (!ThisAdjustment.isEmpty())
ThisAdjustments.push_back(std::make_pair(Components.size(),
ThisAdjustment));
// Add the function.
Components.push_back(VtableComponent::MakeFunction(MD));
}
@ -847,7 +906,13 @@ VtableBuilder::AddMethods(BaseSubobject Base, PrimaryBasesSetTy &PrimaryBases) {
ReturnAdjustment ReturnAdjustment =
ComputeReturnAdjustment(ReturnAdjustmentOffset);
AddMethod(Overrider.Method, ReturnAdjustment);
// Check if this overrider needs a 'this' pointer adjustment.
FinalOverriders::BaseOffset ThisAdjustmentOffset =
Overriders.getThisAdjustmentOffset(Base, MD);
ThisAdjustment ThisAdjustment = ComputeThisAdjustment(ThisAdjustmentOffset);
AddMethod(Overrider.Method, ReturnAdjustment, ThisAdjustment);
}
}
@ -927,6 +992,7 @@ void VtableBuilder::dumpLayout(llvm::raw_ostream& Out) {
}
unsigned NextReturnAdjustmentIndex = 0;
unsigned NextThisAdjustmentIndex = 0;
for (unsigned I = 0, E = Components.size(); I != E; ++I) {
uint64_t Index = I;
@ -990,7 +1056,7 @@ void VtableBuilder::dumpLayout(llvm::raw_ostream& Out) {
if (MD->isPure())
Out << " [pure]";
// If this function pointer has a return adjustment thunk, dump it.
// If this function pointer has a return adjustment, dump it.
if (NextReturnAdjustmentIndex < ReturnAdjustments.size() &&
ReturnAdjustments[NextReturnAdjustmentIndex].first == I) {
const ReturnAdjustment Adjustment =
@ -1006,6 +1072,20 @@ void VtableBuilder::dumpLayout(llvm::raw_ostream& Out) {
NextReturnAdjustmentIndex++;
}
// If this function pointer has a 'this' pointer adjustment, dump it.
if (NextThisAdjustmentIndex < ThisAdjustments.size() &&
ThisAdjustments[NextThisAdjustmentIndex].first == I) {
const ThisAdjustment Adjustment =
ThisAdjustments[NextThisAdjustmentIndex].second;
Out << "\n [this adjustment: ";
Out << Adjustment.NonVirtual << " non-virtual";
Out << ']';
NextThisAdjustmentIndex++;
}
break;
}

47
clang/test/CodeGenCXX/vtable-layout.cpp
View File

@ -1,6 +1,16 @@
// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm-only -fdump-vtable-layouts 2>&1 | FileCheck %s
namespace Test1 {
// For now, just verify this doesn't crash.
namespace test0 {
struct Obj {};
struct Base { virtual const Obj *foo() = 0; };
struct Derived : Base { virtual Obj *foo() { return new Obj(); } };
void test(Derived *D) { D->foo(); }
}
namespace Test1 {
// CHECK: Vtable for 'Test1::A' (3 entries).
// CHECK-NEXT: 0 | offset_to_top (0)
// CHECK-NEXT: 1 | Test1::A RTTI
@ -202,7 +212,7 @@ void F::g() { }
namespace Test5 {
// Simple secondary vtables without this-adjustments.
// Simple secondary vtables without 'this' pointer adjustments.
struct A {
virtual void f();
virtual void g();
@ -240,12 +250,33 @@ struct C : B1, B2 {
void C::h() { }
}
// For now, just verify this doesn't crash.
namespace test0 {
struct Obj {};
namespace Test6 {
struct Base { virtual const Obj *foo() = 0; };
struct Derived : Base { virtual Obj *foo() { return new Obj(); } };
// Simple non-virtual 'this' pointer adjustments.
struct A1 {
virtual void f();
int a;
};
struct A2 {
virtual void f();
int a;
};
// CHECK: Vtable for 'Test6::C' (6 entries).
// CHECK-NEXT: 0 | offset_to_top (0)
// CHECK-NEXT: 1 | Test6::C RTTI
// CHECK-NEXT: -- (Test6::A1, 0) vtable address --
// CHECK-NEXT: -- (Test6::C, 0) vtable address --
// CHECK-NEXT: 2 | void Test6::C::f()
// CHECK-NEXT: 3 | offset_to_top (-16)
// CHECK-NEXT: 4 | Test6::C RTTI
// CHECK-NEXT: -- (Test6::A2, 16) vtable address --
// CHECK-NEXT: 5 | void Test6::C::f()
// CHECK-NEXT: [this adjustment: -16 non-virtual]
struct C : A1, A2 {
virtual void f();
};
void C::f() { }
void test(Derived *D) { D->foo(); }
}