dblaikie updated this revision to Diff 465957.
dblaikie added a comment.
Fix to use CXXABI
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D135326/new/
https://reviews.llvm.org/D135326
Files:
clang/include/clang/Basic/TargetCXXABI.h
clang/include/clang/Basic/TargetInfo.h
clang/lib/AST/RecordLayoutBuilder.cpp
clang/lib/Basic/Targets/OSTargets.h
Index: clang/lib/Basic/Targets/OSTargets.h
===================================================================
--- clang/lib/Basic/Targets/OSTargets.h
+++ clang/lib/Basic/Targets/OSTargets.h
@@ -13,6 +13,7 @@
#define LLVM_CLANG_LIB_BASIC_TARGETS_OSTARGETS_H
#include "Targets.h"
+#include "llvm/ADT/Triple.h"
namespace clang {
namespace targets {
@@ -161,6 +162,16 @@
: TargetInfo::UnsignedLongLong)
: TargetInfo::getLeastIntTypeByWidth(BitWidth, IsSigned);
}
+
+ TargetInfo::TailPaddingUseRules getTailPaddingUseRules() const override {
+ auto CXXABI = this->getCXXABI().getKind();
+ if (CXXABI == TargetCXXABI::iOS)
+ return TargetInfo::UseTailPaddingUnlessPOD03;
+ if (CXXABI == TargetCXXABI::WatchOS ||
+ CXXABI == TargetCXXABI::AppleARM64)
+ return TargetInfo::UseTailPaddingUnlessPOD11;
+ return TargetInfo::UseTailPaddingUnlessPOD03;
+ }
};
// DragonFlyBSD Target
@@ -845,6 +856,11 @@
this->WCharType = TargetInfo::UnsignedShort;
this->WIntType = TargetInfo::UnsignedShort;
}
+ TargetInfo::TailPaddingUseRules getTailPaddingUseRules() const override {
+ if (this->getTriple().isWindowsMSVCEnvironment())
+ return TargetInfo::AlwaysUseTailPadding;
+ return TargetInfo::UseTailPaddingUnlessPOD03;
+ }
};
template <typename Target>
@@ -922,6 +938,9 @@
this->MCountName = "__mcount";
this->TheCXXABI.set(TargetCXXABI::Fuchsia);
}
+ TargetInfo::TailPaddingUseRules getTailPaddingUseRules() const override {
+ return TargetInfo::UseTailPaddingUnlessPOD11;
+ }
};
// WebAssembly target
@@ -949,6 +968,9 @@
this->TheCXXABI.set(TargetCXXABI::WebAssembly);
this->HasFloat128 = true;
}
+ TargetInfo::TailPaddingUseRules getTailPaddingUseRules() const override {
+ return TargetInfo::UseTailPaddingUnlessPOD11;
+ }
};
// WASI target
Index: clang/lib/AST/RecordLayoutBuilder.cpp
===================================================================
--- clang/lib/AST/RecordLayoutBuilder.cpp
+++ clang/lib/AST/RecordLayoutBuilder.cpp
@@ -2392,12 +2392,12 @@
/// Does the target C++ ABI require us to skip over the tail-padding
/// of the given class (considering it as a base class) when allocating
/// objects?
-static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD) {
- switch (ABI.getTailPaddingUseRules()) {
- case TargetCXXABI::AlwaysUseTailPadding:
+static bool mustSkipTailPadding(const TargetInfo &TI, const CXXRecordDecl *RD) {
+ switch (TI.getTailPaddingUseRules()) {
+ case TargetInfo::AlwaysUseTailPadding:
return false;
- case TargetCXXABI::UseTailPaddingUnlessPOD03:
+ case TargetInfo::UseTailPaddingUnlessPOD03:
// FIXME: To the extent that this is meant to cover the Itanium ABI
// rules, we should implement the restrictions about over-sized
// bitfields:
@@ -2418,7 +2418,7 @@
// intended.
return RD->isPOD();
- case TargetCXXABI::UseTailPaddingUnlessPOD11:
+ case TargetInfo::UseTailPaddingUnlessPOD11:
// This is equivalent to RD->getTypeForDecl().isCXX11PODType(),
// but with a lot of abstraction penalty stripped off. This does
// assume that these properties are set correctly even in C++98
@@ -3319,7 +3319,7 @@
// tail-padding of base classes. This is ABI-dependent.
// FIXME: this should be stored in the record layout.
bool skipTailPadding =
- mustSkipTailPadding(getTargetInfo().getCXXABI(), RD);
+ mustSkipTailPadding(getTargetInfo(), RD);
// FIXME: This should be done in FinalizeLayout.
CharUnits DataSize =
Index: clang/include/clang/Basic/TargetInfo.h
===================================================================
--- clang/include/clang/Basic/TargetInfo.h
+++ clang/include/clang/Basic/TargetInfo.h
@@ -945,6 +945,14 @@
virtual void getTargetDefines(const LangOptions &Opts,
MacroBuilder &Builder) const = 0;
+ enum TailPaddingUseRules {
+ AlwaysUseTailPadding,
+ UseTailPaddingUnlessPOD03,
+ UseTailPaddingUnlessPOD11
+ };
+ virtual TailPaddingUseRules getTailPaddingUseRules() const {
+ return UseTailPaddingUnlessPOD03;
+ }
/// Return information about target-specific builtins for
/// the current primary target, and info about which builtins are non-portable
Index: clang/include/clang/Basic/TargetCXXABI.h
===================================================================
--- clang/include/clang/Basic/TargetCXXABI.h
+++ clang/include/clang/Basic/TargetCXXABI.h
@@ -257,57 +257,6 @@
llvm_unreachable("bad ABI kind");
}
- /// When is record layout allowed to allocate objects in the tail
- /// padding of a base class?
- ///
- /// This decision cannot be changed without breaking platform ABI
- /// compatibility. In ISO C++98, tail padding reuse was only permitted for
- /// non-POD base classes, but that restriction was removed retroactively by
- /// DR 43, and tail padding reuse is always permitted in all de facto C++
- /// language modes. However, many platforms use a variant of the old C++98
- /// rule for compatibility.
- enum TailPaddingUseRules {
- /// The tail-padding of a base class is always theoretically
- /// available, even if it's POD.
- AlwaysUseTailPadding,
-
- /// Only allocate objects in the tail padding of a base class if
- /// the base class is not POD according to the rules of C++ TR1.
- UseTailPaddingUnlessPOD03,
-
- /// Only allocate objects in the tail padding of a base class if
- /// the base class is not POD according to the rules of C++11.
- UseTailPaddingUnlessPOD11
- };
- TailPaddingUseRules getTailPaddingUseRules() const {
- switch (getKind()) {
- // To preserve binary compatibility, the generic Itanium ABI has
- // permanently locked the definition of POD to the rules of C++ TR1,
- // and that trickles down to derived ABIs.
- case GenericItanium:
- case GenericAArch64:
- case GenericARM:
- case iOS:
- case GenericMIPS:
- case XL:
- return UseTailPaddingUnlessPOD03;
-
- // AppleARM64 and WebAssembly use the C++11 POD rules. They do not honor
- // the Itanium exception about classes with over-large bitfields.
- case AppleARM64:
- case Fuchsia:
- case WebAssembly:
- case WatchOS:
- return UseTailPaddingUnlessPOD11;
-
- // MSVC always allocates fields in the tail-padding of a base class
- // subobject, even if they're POD.
- case Microsoft:
- return AlwaysUseTailPadding;
- }
- llvm_unreachable("bad ABI kind");
- }
-
friend bool operator==(const TargetCXXABI &left, const TargetCXXABI &right) {
return left.getKind() == right.getKind();
}
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