[clang][NFC] Remove class layout scissor #89055
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@llvm/pr-subscribers-clang Author: Nathan Sidwell (urnathan) ChangesNow that Full diff: https://github.com/llvm/llvm-project/pull/89055.diff 1 Files Affected:
diff --git a/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp b/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
index 868b1ab98e048a..38167903cda508 100644
--- a/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -75,7 +75,7 @@ struct CGRecordLowering {
// sentinel member type that ensures correct rounding.
struct MemberInfo {
CharUnits Offset;
- enum InfoKind { VFPtr, VBPtr, Field, Base, VBase, Scissor } Kind;
+ enum InfoKind { VFPtr, VBPtr, Field, Base, VBase } Kind;
llvm::Type *Data;
union {
const FieldDecl *FD;
@@ -197,7 +197,7 @@ struct CGRecordLowering {
const CXXRecordDecl *Query) const;
void calculateZeroInit();
CharUnits calculateTailClippingOffset(bool isNonVirtualBaseType) const;
- void checkBitfieldClipping() const;
+ void checkBitfieldClipping(bool isNonVirtualBaseType) const;
/// Determines if we need a packed llvm struct.
void determinePacked(bool NVBaseType);
/// Inserts padding everywhere it's needed.
@@ -299,8 +299,8 @@ void CGRecordLowering::lower(bool NVBaseType) {
accumulateVBases();
}
llvm::stable_sort(Members);
+ checkBitfieldClipping(NVBaseType);
Members.push_back(StorageInfo(Size, getIntNType(8)));
- checkBitfieldClipping();
determinePacked(NVBaseType);
insertPadding();
Members.pop_back();
@@ -894,8 +894,6 @@ CGRecordLowering::calculateTailClippingOffset(bool isNonVirtualBaseType) const {
}
void CGRecordLowering::accumulateVBases() {
- Members.push_back(MemberInfo(calculateTailClippingOffset(false),
- MemberInfo::Scissor, nullptr, RD));
for (const auto &Base : RD->vbases()) {
const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
if (BaseDecl->isEmpty())
@@ -950,18 +948,20 @@ void CGRecordLowering::calculateZeroInit() {
}
// Verify accumulateBitfields computed the correct storage representations.
-void CGRecordLowering::checkBitfieldClipping() const {
+void CGRecordLowering::checkBitfieldClipping(
+ bool IsNonVirtualBaseType LLVM_ATTRIBUTE_UNUSED) const {
#ifndef NDEBUG
+ auto ScissorOffset = calculateTailClippingOffset(IsNonVirtualBaseType);
auto Tail = CharUnits::Zero();
for (const auto &M : Members) {
- // Only members with data and the scissor can cut into tail padding.
- if (!M.Data && M.Kind != MemberInfo::Scissor)
+ // Only members with data could possibly overlap.
+ if (!M.Data)
continue;
assert(M.Offset >= Tail && "Bitfield access unit is not clipped");
- Tail = M.Offset;
- if (M.Data)
- Tail += getSize(M.Data);
+ Tail = M.Offset + getSize(M.Data);
+ assert((Tail <= ScissorOffset || M.Offset >= ScissorOffset) &&
+ "Bitfield straddles scissor offset");
}
#endif
}
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@llvm/pr-subscribers-clang-codegen Author: Nathan Sidwell (urnathan) ChangesNow that Full diff: https://github.com/llvm/llvm-project/pull/89055.diff 1 Files Affected:
diff --git a/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp b/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
index 868b1ab98e048a..38167903cda508 100644
--- a/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -75,7 +75,7 @@ struct CGRecordLowering {
// sentinel member type that ensures correct rounding.
struct MemberInfo {
CharUnits Offset;
- enum InfoKind { VFPtr, VBPtr, Field, Base, VBase, Scissor } Kind;
+ enum InfoKind { VFPtr, VBPtr, Field, Base, VBase } Kind;
llvm::Type *Data;
union {
const FieldDecl *FD;
@@ -197,7 +197,7 @@ struct CGRecordLowering {
const CXXRecordDecl *Query) const;
void calculateZeroInit();
CharUnits calculateTailClippingOffset(bool isNonVirtualBaseType) const;
- void checkBitfieldClipping() const;
+ void checkBitfieldClipping(bool isNonVirtualBaseType) const;
/// Determines if we need a packed llvm struct.
void determinePacked(bool NVBaseType);
/// Inserts padding everywhere it's needed.
@@ -299,8 +299,8 @@ void CGRecordLowering::lower(bool NVBaseType) {
accumulateVBases();
}
llvm::stable_sort(Members);
+ checkBitfieldClipping(NVBaseType);
Members.push_back(StorageInfo(Size, getIntNType(8)));
- checkBitfieldClipping();
determinePacked(NVBaseType);
insertPadding();
Members.pop_back();
@@ -894,8 +894,6 @@ CGRecordLowering::calculateTailClippingOffset(bool isNonVirtualBaseType) const {
}
void CGRecordLowering::accumulateVBases() {
- Members.push_back(MemberInfo(calculateTailClippingOffset(false),
- MemberInfo::Scissor, nullptr, RD));
for (const auto &Base : RD->vbases()) {
const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
if (BaseDecl->isEmpty())
@@ -950,18 +948,20 @@ void CGRecordLowering::calculateZeroInit() {
}
// Verify accumulateBitfields computed the correct storage representations.
-void CGRecordLowering::checkBitfieldClipping() const {
+void CGRecordLowering::checkBitfieldClipping(
+ bool IsNonVirtualBaseType LLVM_ATTRIBUTE_UNUSED) const {
#ifndef NDEBUG
+ auto ScissorOffset = calculateTailClippingOffset(IsNonVirtualBaseType);
auto Tail = CharUnits::Zero();
for (const auto &M : Members) {
- // Only members with data and the scissor can cut into tail padding.
- if (!M.Data && M.Kind != MemberInfo::Scissor)
+ // Only members with data could possibly overlap.
+ if (!M.Data)
continue;
assert(M.Offset >= Tail && "Bitfield access unit is not clipped");
- Tail = M.Offset;
- if (M.Data)
- Tail += getSize(M.Data);
+ Tail = M.Offset + getSize(M.Data);
+ assert((Tail <= ScissorOffset || M.Offset >= ScissorOffset) &&
+ "Bitfield straddles scissor offset");
}
#endif
}
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urnathan
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Now that
accumulateBitfieldsdoes the correct clipping, we don't need the scissor any more --checkBitfieldClippingcan compute its location directly.