[clang][RISCV] Emit RISCV function-signature-based CFI label in llvm::Function metadata #111661
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@llvm/pr-subscribers-backend-risc-v @llvm/pr-subscribers-clang Author: Ming-Yi Lai (mylai-mtk) ChangesThis method calculates a CFI label used in the RISC-V Zicfilp func-sig CFI scheme for a given function type/declaration. The scheme, according to psABI, encodes the label based on function signature, and the rules are modified from the Itanium C++ ABI mangling rule to allow functions (callees) that are called indirectly to have the expected label as indicated by the function pointer type seen at the call site (caller). This method is a pre-requisite to enable RISC-V Zicfilp CFI with func-sig label scheme. The implemented psABI scheme can be found at riscv-non-isa/riscv-elf-psabi-doc#434 . Full diff: https://github.com/llvm/llvm-project/pull/111661.diff 6 Files Affected:
diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
index a4d36f2eacd5d1..4812e0bac2cfc3 100644
--- a/clang/include/clang/AST/ASTContext.h
+++ b/clang/include/clang/AST/ASTContext.h
@@ -1876,6 +1876,9 @@ class ASTContext : public RefCountedBase<ASTContext> {
/// (struct/union/class/enum) decl.
QualType getTagDeclType(const TagDecl *Decl) const;
+ /// Return the type for "void *"
+ QualType getVoidPtrType() const { return VoidPtrTy; }
+
/// Return the unique type for "size_t" (C99 7.17), defined in
/// <stddef.h>.
///
@@ -1903,6 +1906,10 @@ class ASTContext : public RefCountedBase<ASTContext> {
/// defined in <stddef.h> as defined by the target.
QualType getWideCharType() const { return WideCharTy; }
+ /// Return the type of wide characters in C context, no matter whether it's C
+ /// or C++ being compiled.
+ QualType getWCharTypeInC() const;
+
/// Return the type of "signed wchar_t".
///
/// Used when in C++, as a GCC extension.
diff --git a/clang/include/clang/AST/Mangle.h b/clang/include/clang/AST/Mangle.h
index d5f6c0f6cc67df..16cbd802177ba4 100644
--- a/clang/include/clang/AST/Mangle.h
+++ b/clang/include/clang/AST/Mangle.h
@@ -212,6 +212,11 @@ class ItaniumMangleContext : public MangleContext {
virtual void mangleModuleInitializer(const Module *Module, raw_ostream &) = 0;
+ virtual void mangleForRISCVZicfilpFuncSigLabel(const FunctionType &FT,
+ const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod,
+ raw_ostream &) = 0;
+
// This has to live here, otherwise the CXXNameMangler won't have access to
// it.
virtual DiscriminatorOverrideTy getDiscriminatorOverride() const = 0;
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 034fbbe0bc7829..ce8688a489cb43 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -6442,6 +6442,12 @@ CanQualType ASTContext::getUIntMaxType() const {
return getFromTargetType(Target->getUIntMaxType());
}
+/// Return the type of wide characters in C context, no matter whether it's C
+/// or C++ being compiled.
+QualType ASTContext::getWCharTypeInC() const {
+ return getFromTargetType(Target->getWCharType());
+}
+
/// getSignedWCharType - Return the type of "signed wchar_t".
/// Used when in C++, as a GCC extension.
QualType ASTContext::getSignedWCharType() const {
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 777cdca1a0c0d7..9eff94b0844092 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -43,6 +43,14 @@ using namespace clang;
namespace {
+static bool mayBeCovariant(const Type &Ty) {
+ if (auto *const PT = Ty.getAs<PointerType>())
+ return PT->getPointeeType()->isStructureOrClassType();
+ if (auto *const RT = Ty.getAs<ReferenceType>())
+ return RT->getPointeeType()->isStructureOrClassType();
+ return false;
+}
+
static bool isLocalContainerContext(const DeclContext *DC) {
return isa<FunctionDecl>(DC) || isa<ObjCMethodDecl>(DC) || isa<BlockDecl>(DC);
}
@@ -136,6 +144,11 @@ class ItaniumMangleContextImpl : public ItaniumMangleContext {
void mangleModuleInitializer(const Module *Module, raw_ostream &) override;
+ void mangleForRISCVZicfilpFuncSigLabel(const FunctionType &,
+ const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod,
+ raw_ostream &) override;
+
bool getNextDiscriminator(const NamedDecl *ND, unsigned &disc) {
// Lambda closure types are already numbered.
if (isLambda(ND))
@@ -395,8 +408,10 @@ class CXXNameMangler {
llvm::DenseMap<uintptr_t, unsigned> Substitutions;
llvm::DenseMap<StringRef, unsigned> ModuleSubstitutions;
+protected:
ASTContext &getASTContext() const { return Context.getASTContext(); }
+private:
bool isCompatibleWith(LangOptions::ClangABI Ver) {
return Context.getASTContext().getLangOpts().getClangABICompat() <= Ver;
}
@@ -443,6 +458,8 @@ class CXXNameMangler {
NullOut = true;
}
+ virtual ~CXXNameMangler() = default;
+
struct WithTemplateDepthOffset { unsigned Offset; };
CXXNameMangler(ItaniumMangleContextImpl &C, raw_ostream &Out,
WithTemplateDepthOffset Offset)
@@ -559,9 +576,12 @@ class CXXNameMangler {
StringRef Prefix = "");
void mangleOperatorName(DeclarationName Name, unsigned Arity);
void mangleOperatorName(OverloadedOperatorKind OO, unsigned Arity);
+
+protected:
void mangleQualifiers(Qualifiers Quals, const DependentAddressSpaceType *DAST = nullptr);
void mangleRefQualifier(RefQualifierKind RefQualifier);
+private:
void mangleObjCMethodName(const ObjCMethodDecl *MD);
// Declare manglers for every type class.
@@ -572,11 +592,24 @@ class CXXNameMangler {
void mangleType(const TagType*);
void mangleType(TemplateName);
+
+protected:
+ // Use the `Impl` scheme instead of directly virtualizing `mangleType`s since
+ // `mangleType`s are declared by tables
+ virtual void mangleTypeImpl(const BuiltinType *T);
+ virtual void mangleTypeImpl(const FunctionProtoType *T);
+ virtual void mangleTypeImpl(const FunctionNoProtoType *T);
+
+private:
static StringRef getCallingConvQualifierName(CallingConv CC);
void mangleExtParameterInfo(FunctionProtoType::ExtParameterInfo info);
void mangleExtFunctionInfo(const FunctionType *T);
+
+protected:
void mangleBareFunctionType(const FunctionProtoType *T, bool MangleReturnType,
const FunctionDecl *FD = nullptr);
+
+private:
void mangleNeonVectorType(const VectorType *T);
void mangleNeonVectorType(const DependentVectorType *T);
void mangleAArch64NeonVectorType(const VectorType *T);
@@ -3058,7 +3091,9 @@ void CXXNameMangler::mangleCXXRecordDecl(const CXXRecordDecl *Record) {
addSubstitution(Record);
}
-void CXXNameMangler::mangleType(const BuiltinType *T) {
+void CXXNameMangler::mangleType(const BuiltinType *T) { mangleTypeImpl(T); }
+
+void CXXNameMangler::mangleTypeImpl(const BuiltinType *T) {
// <type> ::= <builtin-type>
// <builtin-type> ::= v # void
// ::= w # wchar_t
@@ -3563,10 +3598,14 @@ CXXNameMangler::mangleExtParameterInfo(FunctionProtoType::ExtParameterInfo PI) {
mangleVendorQualifier("noescape");
}
+void CXXNameMangler::mangleType(const FunctionProtoType *T) {
+ return mangleTypeImpl(T);
+}
+
// <type> ::= <function-type>
// <function-type> ::= [<CV-qualifiers>] F [Y]
// <bare-function-type> [<ref-qualifier>] E
-void CXXNameMangler::mangleType(const FunctionProtoType *T) {
+void CXXNameMangler::mangleTypeImpl(const FunctionProtoType *T) {
mangleExtFunctionInfo(T);
// Mangle CV-qualifiers, if present. These are 'this' qualifiers,
@@ -3604,6 +3643,10 @@ void CXXNameMangler::mangleType(const FunctionProtoType *T) {
}
void CXXNameMangler::mangleType(const FunctionNoProtoType *T) {
+ return mangleTypeImpl(T);
+}
+
+void CXXNameMangler::mangleTypeImpl(const FunctionNoProtoType *T) {
// Function types without prototypes can arise when mangling a function type
// within an overloadable function in C. We mangle these as the absence of any
// parameter types (not even an empty parameter list).
@@ -7074,6 +7117,85 @@ bool CXXNameMangler::shouldHaveAbiTags(ItaniumMangleContextImpl &C,
return TrackAbiTags.AbiTagsRoot.getUsedAbiTags().size();
}
+namespace {
+
+class RISCVZicfilpFuncSigLabelMangler : public CXXNameMangler {
+ bool IsTopLevelAndCXXVirtualMethod;
+
+public:
+ RISCVZicfilpFuncSigLabelMangler(ItaniumMangleContextImpl &C, raw_ostream &Out,
+ const bool IsCXXVirtualMethod)
+ : CXXNameMangler(C, Out),
+ IsTopLevelAndCXXVirtualMethod(/*IsTopLevel=*/true &&
+ IsCXXVirtualMethod) {}
+
+ void mangleTypeImpl(const BuiltinType *T) override {
+ if (T->getKind() == BuiltinType::WChar_S ||
+ T->getKind() == BuiltinType::WChar_U) {
+ const Type *const OverrideT =
+ getASTContext().getWCharTypeInC().getTypePtr();
+ assert(isa<BuiltinType>(OverrideT) &&
+ "`wchar_t' in C is expected to be defined to a built-in type");
+ T = static_cast<const BuiltinType *>(OverrideT);
+ }
+ return CXXNameMangler::mangleTypeImpl(T);
+ }
+
+ // This <function-type> is the RISC-V psABI modified version
+ // <function-type> ::= [<CV-qualifiers>] [Dx] F <bare-function-type>
+ // [<ref-qualifier>] E
+ void mangleTypeImpl(const FunctionProtoType *T) override {
+ // Mangle CV-qualifiers, if present. These are 'this' qualifiers,
+ // e.g. "const" in "int (A::*)() const".
+ mangleQualifiers(T->getMethodQuals());
+
+ getStream() << 'F';
+
+ bool MangleReturnType = true;
+ if (const Type &RetT = *T->getReturnType().getTypePtr();
+ IsTopLevelAndCXXVirtualMethod && mayBeCovariant(RetT)) {
+ // Possible covariant types mangle dummy cv-unqualified `class v` as its
+ // class type
+ if (RetT.isPointerType())
+ getStream() << "P1v";
+ else if (RetT.isLValueReferenceType())
+ getStream() << "R1v";
+ else {
+ assert(RetT.isRValueReferenceType() &&
+ "Expect an r-value ref for covariant return type that is not a "
+ "pointer or an l-value ref");
+ getStream() << "O1v";
+ }
+
+ IsTopLevelAndCXXVirtualMethod = false; // Not top-level anymore
+ MangleReturnType = false;
+ }
+ mangleBareFunctionType(T, MangleReturnType);
+
+ // Mangle the ref-qualifier, if present.
+ mangleRefQualifier(T->getRefQualifier());
+
+ getStream() << 'E';
+ }
+
+ void mangleTypeImpl(const FunctionNoProtoType *T) override {
+ return CXXNameMangler::mangleTypeImpl(toFunctionProtoType(T));
+ }
+
+private:
+ const FunctionProtoType *
+ toFunctionProtoType(const FunctionNoProtoType *const T) {
+ FunctionProtoType::ExtProtoInfo EPI;
+ EPI.ExtInfo = T->getExtInfo();
+ const Type *const NewT = getASTContext()
+ .getFunctionType(T->getReturnType(), {}, EPI)
+ .getTypePtr();
+ return static_cast<const FunctionProtoType *>(NewT);
+ }
+}; // class RISCVZicfilpFuncSigLabelMangler
+
+} // anonymous namespace
+
//
/// Mangles the name of the declaration D and emits that name to the given
@@ -7412,6 +7534,17 @@ void ItaniumMangleContextImpl::mangleModuleInitializer(const Module *M,
}
}
+void ItaniumMangleContextImpl::mangleForRISCVZicfilpFuncSigLabel(
+ const FunctionType &FT, const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod, raw_ostream &Out) {
+ if (IsCXXInstanceMethod)
+ // member methods uses a dummy class named `v` in place of real classes
+ Out << "M1v";
+
+ RISCVZicfilpFuncSigLabelMangler Mangler(*this, Out, IsCXXVirtualMethod);
+ Mangler.mangleType(QualType(&FT, 0));
+}
+
ItaniumMangleContext *ItaniumMangleContext::create(ASTContext &Context,
DiagnosticsEngine &Diags,
bool IsAux) {
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 5ba098144a74e7..c7b6b56690c9ab 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2829,6 +2829,56 @@ void CodeGenModule::CreateFunctionTypeMetadataForIcall(const FunctionDecl *FD,
F->addTypeMetadata(0, llvm::ConstantAsMetadata::get(CrossDsoTypeId));
}
+uint32_t
+CodeGenModule::calcRISCVZicfilpFuncSigLabel(const FunctionType &FT,
+ const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod) {
+ std::string OutName;
+ llvm::raw_string_ostream Out(OutName);
+ MangleContext &MC = getCXXABI().getMangleContext();
+ cast<ItaniumMangleContext>(MC).mangleForRISCVZicfilpFuncSigLabel(
+ FT, IsCXXInstanceMethod, IsCXXVirtualMethod, Out);
+
+ const llvm::MD5::MD5Result MD5Result =
+ llvm::MD5::hash({(const uint8_t *)OutName.data(), OutName.size()});
+
+ // Take 20 bits of MD5 result with the approach specified by psABI
+ uint64_t MD5High = MD5Result.high();
+ uint64_t MD5Low = MD5Result.low();
+ while (MD5High && MD5Low) {
+ const uint32_t Low20Bits = MD5Low & 0xFFFFFULL;
+ if (Low20Bits)
+ return Low20Bits;
+
+ // Logical right shift MD5 result by 20 bits
+ MD5Low = (MD5High & 0xFFFFF) << 44 | MD5Low >> 20;
+ MD5High >>= 20;
+ }
+
+ return llvm::MD5Hash("RISC-V") & 0xFFFFFULL;
+}
+
+uint32_t CodeGenModule::calcRISCVZicfilpFuncSigLabel(const FunctionDecl &FD) {
+ if (FD.isMain())
+ // All main functions use `int main(int, char**)` for label calculation
+ // according to psABI spec. This value is the pre-calculated label.
+ return 0xd0639;
+
+ if (isa<CXXDestructorDecl>(FD))
+ // All destructors use `void (void*)` for label calculation according to the
+ // psABI spec. This value is the pre-calculated label.
+ return 0x639c2;
+
+ bool IsCXXInstanceMethod = false;
+ bool IsCXXVirtualMethod = false;
+ if (const auto *const MD = dyn_cast<CXXMethodDecl>(&FD)) {
+ IsCXXInstanceMethod = MD->isInstance();
+ IsCXXVirtualMethod = MD->isVirtual();
+ }
+ return calcRISCVZicfilpFuncSigLabel(*FD.getFunctionType(),
+ IsCXXInstanceMethod, IsCXXVirtualMethod);
+}
+
void CodeGenModule::setKCFIType(const FunctionDecl *FD, llvm::Function *F) {
llvm::LLVMContext &Ctx = F->getContext();
llvm::MDBuilder MDB(Ctx);
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index c58bb88035ca8a..937b7c8a11b060 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -1559,6 +1559,14 @@ class CodeGenModule : public CodeGenTypeCache {
/// Emit KCFI type identifier constants and remove unused identifiers.
void finalizeKCFITypes();
+ /// Calculate RISC-V Zicfilp func-sig scheme CFI label
+ uint32_t calcRISCVZicfilpFuncSigLabel(const FunctionType &FT,
+ const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod);
+
+ /// Calculate RISC-V Zicfilp func-sig scheme CFI label
+ uint32_t calcRISCVZicfilpFuncSigLabel(const FunctionDecl &FD);
+
/// Whether this function's return type has no side effects, and thus may
/// be trivially discarded if it is unused.
bool MayDropFunctionReturn(const ASTContext &Context,
|
|
@llvm/pr-subscribers-clang-codegen Author: Ming-Yi Lai (mylai-mtk) ChangesThis method calculates a CFI label used in the RISC-V Zicfilp func-sig CFI scheme for a given function type/declaration. The scheme, according to psABI, encodes the label based on function signature, and the rules are modified from the Itanium C++ ABI mangling rule to allow functions (callees) that are called indirectly to have the expected label as indicated by the function pointer type seen at the call site (caller). This method is a pre-requisite to enable RISC-V Zicfilp CFI with func-sig label scheme. The implemented psABI scheme can be found at riscv-non-isa/riscv-elf-psabi-doc#434 . Full diff: https://github.com/llvm/llvm-project/pull/111661.diff 6 Files Affected:
diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
index a4d36f2eacd5d1..4812e0bac2cfc3 100644
--- a/clang/include/clang/AST/ASTContext.h
+++ b/clang/include/clang/AST/ASTContext.h
@@ -1876,6 +1876,9 @@ class ASTContext : public RefCountedBase<ASTContext> {
/// (struct/union/class/enum) decl.
QualType getTagDeclType(const TagDecl *Decl) const;
+ /// Return the type for "void *"
+ QualType getVoidPtrType() const { return VoidPtrTy; }
+
/// Return the unique type for "size_t" (C99 7.17), defined in
/// <stddef.h>.
///
@@ -1903,6 +1906,10 @@ class ASTContext : public RefCountedBase<ASTContext> {
/// defined in <stddef.h> as defined by the target.
QualType getWideCharType() const { return WideCharTy; }
+ /// Return the type of wide characters in C context, no matter whether it's C
+ /// or C++ being compiled.
+ QualType getWCharTypeInC() const;
+
/// Return the type of "signed wchar_t".
///
/// Used when in C++, as a GCC extension.
diff --git a/clang/include/clang/AST/Mangle.h b/clang/include/clang/AST/Mangle.h
index d5f6c0f6cc67df..16cbd802177ba4 100644
--- a/clang/include/clang/AST/Mangle.h
+++ b/clang/include/clang/AST/Mangle.h
@@ -212,6 +212,11 @@ class ItaniumMangleContext : public MangleContext {
virtual void mangleModuleInitializer(const Module *Module, raw_ostream &) = 0;
+ virtual void mangleForRISCVZicfilpFuncSigLabel(const FunctionType &FT,
+ const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod,
+ raw_ostream &) = 0;
+
// This has to live here, otherwise the CXXNameMangler won't have access to
// it.
virtual DiscriminatorOverrideTy getDiscriminatorOverride() const = 0;
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 034fbbe0bc7829..ce8688a489cb43 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -6442,6 +6442,12 @@ CanQualType ASTContext::getUIntMaxType() const {
return getFromTargetType(Target->getUIntMaxType());
}
+/// Return the type of wide characters in C context, no matter whether it's C
+/// or C++ being compiled.
+QualType ASTContext::getWCharTypeInC() const {
+ return getFromTargetType(Target->getWCharType());
+}
+
/// getSignedWCharType - Return the type of "signed wchar_t".
/// Used when in C++, as a GCC extension.
QualType ASTContext::getSignedWCharType() const {
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 777cdca1a0c0d7..9eff94b0844092 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -43,6 +43,14 @@ using namespace clang;
namespace {
+static bool mayBeCovariant(const Type &Ty) {
+ if (auto *const PT = Ty.getAs<PointerType>())
+ return PT->getPointeeType()->isStructureOrClassType();
+ if (auto *const RT = Ty.getAs<ReferenceType>())
+ return RT->getPointeeType()->isStructureOrClassType();
+ return false;
+}
+
static bool isLocalContainerContext(const DeclContext *DC) {
return isa<FunctionDecl>(DC) || isa<ObjCMethodDecl>(DC) || isa<BlockDecl>(DC);
}
@@ -136,6 +144,11 @@ class ItaniumMangleContextImpl : public ItaniumMangleContext {
void mangleModuleInitializer(const Module *Module, raw_ostream &) override;
+ void mangleForRISCVZicfilpFuncSigLabel(const FunctionType &,
+ const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod,
+ raw_ostream &) override;
+
bool getNextDiscriminator(const NamedDecl *ND, unsigned &disc) {
// Lambda closure types are already numbered.
if (isLambda(ND))
@@ -395,8 +408,10 @@ class CXXNameMangler {
llvm::DenseMap<uintptr_t, unsigned> Substitutions;
llvm::DenseMap<StringRef, unsigned> ModuleSubstitutions;
+protected:
ASTContext &getASTContext() const { return Context.getASTContext(); }
+private:
bool isCompatibleWith(LangOptions::ClangABI Ver) {
return Context.getASTContext().getLangOpts().getClangABICompat() <= Ver;
}
@@ -443,6 +458,8 @@ class CXXNameMangler {
NullOut = true;
}
+ virtual ~CXXNameMangler() = default;
+
struct WithTemplateDepthOffset { unsigned Offset; };
CXXNameMangler(ItaniumMangleContextImpl &C, raw_ostream &Out,
WithTemplateDepthOffset Offset)
@@ -559,9 +576,12 @@ class CXXNameMangler {
StringRef Prefix = "");
void mangleOperatorName(DeclarationName Name, unsigned Arity);
void mangleOperatorName(OverloadedOperatorKind OO, unsigned Arity);
+
+protected:
void mangleQualifiers(Qualifiers Quals, const DependentAddressSpaceType *DAST = nullptr);
void mangleRefQualifier(RefQualifierKind RefQualifier);
+private:
void mangleObjCMethodName(const ObjCMethodDecl *MD);
// Declare manglers for every type class.
@@ -572,11 +592,24 @@ class CXXNameMangler {
void mangleType(const TagType*);
void mangleType(TemplateName);
+
+protected:
+ // Use the `Impl` scheme instead of directly virtualizing `mangleType`s since
+ // `mangleType`s are declared by tables
+ virtual void mangleTypeImpl(const BuiltinType *T);
+ virtual void mangleTypeImpl(const FunctionProtoType *T);
+ virtual void mangleTypeImpl(const FunctionNoProtoType *T);
+
+private:
static StringRef getCallingConvQualifierName(CallingConv CC);
void mangleExtParameterInfo(FunctionProtoType::ExtParameterInfo info);
void mangleExtFunctionInfo(const FunctionType *T);
+
+protected:
void mangleBareFunctionType(const FunctionProtoType *T, bool MangleReturnType,
const FunctionDecl *FD = nullptr);
+
+private:
void mangleNeonVectorType(const VectorType *T);
void mangleNeonVectorType(const DependentVectorType *T);
void mangleAArch64NeonVectorType(const VectorType *T);
@@ -3058,7 +3091,9 @@ void CXXNameMangler::mangleCXXRecordDecl(const CXXRecordDecl *Record) {
addSubstitution(Record);
}
-void CXXNameMangler::mangleType(const BuiltinType *T) {
+void CXXNameMangler::mangleType(const BuiltinType *T) { mangleTypeImpl(T); }
+
+void CXXNameMangler::mangleTypeImpl(const BuiltinType *T) {
// <type> ::= <builtin-type>
// <builtin-type> ::= v # void
// ::= w # wchar_t
@@ -3563,10 +3598,14 @@ CXXNameMangler::mangleExtParameterInfo(FunctionProtoType::ExtParameterInfo PI) {
mangleVendorQualifier("noescape");
}
+void CXXNameMangler::mangleType(const FunctionProtoType *T) {
+ return mangleTypeImpl(T);
+}
+
// <type> ::= <function-type>
// <function-type> ::= [<CV-qualifiers>] F [Y]
// <bare-function-type> [<ref-qualifier>] E
-void CXXNameMangler::mangleType(const FunctionProtoType *T) {
+void CXXNameMangler::mangleTypeImpl(const FunctionProtoType *T) {
mangleExtFunctionInfo(T);
// Mangle CV-qualifiers, if present. These are 'this' qualifiers,
@@ -3604,6 +3643,10 @@ void CXXNameMangler::mangleType(const FunctionProtoType *T) {
}
void CXXNameMangler::mangleType(const FunctionNoProtoType *T) {
+ return mangleTypeImpl(T);
+}
+
+void CXXNameMangler::mangleTypeImpl(const FunctionNoProtoType *T) {
// Function types without prototypes can arise when mangling a function type
// within an overloadable function in C. We mangle these as the absence of any
// parameter types (not even an empty parameter list).
@@ -7074,6 +7117,85 @@ bool CXXNameMangler::shouldHaveAbiTags(ItaniumMangleContextImpl &C,
return TrackAbiTags.AbiTagsRoot.getUsedAbiTags().size();
}
+namespace {
+
+class RISCVZicfilpFuncSigLabelMangler : public CXXNameMangler {
+ bool IsTopLevelAndCXXVirtualMethod;
+
+public:
+ RISCVZicfilpFuncSigLabelMangler(ItaniumMangleContextImpl &C, raw_ostream &Out,
+ const bool IsCXXVirtualMethod)
+ : CXXNameMangler(C, Out),
+ IsTopLevelAndCXXVirtualMethod(/*IsTopLevel=*/true &&
+ IsCXXVirtualMethod) {}
+
+ void mangleTypeImpl(const BuiltinType *T) override {
+ if (T->getKind() == BuiltinType::WChar_S ||
+ T->getKind() == BuiltinType::WChar_U) {
+ const Type *const OverrideT =
+ getASTContext().getWCharTypeInC().getTypePtr();
+ assert(isa<BuiltinType>(OverrideT) &&
+ "`wchar_t' in C is expected to be defined to a built-in type");
+ T = static_cast<const BuiltinType *>(OverrideT);
+ }
+ return CXXNameMangler::mangleTypeImpl(T);
+ }
+
+ // This <function-type> is the RISC-V psABI modified version
+ // <function-type> ::= [<CV-qualifiers>] [Dx] F <bare-function-type>
+ // [<ref-qualifier>] E
+ void mangleTypeImpl(const FunctionProtoType *T) override {
+ // Mangle CV-qualifiers, if present. These are 'this' qualifiers,
+ // e.g. "const" in "int (A::*)() const".
+ mangleQualifiers(T->getMethodQuals());
+
+ getStream() << 'F';
+
+ bool MangleReturnType = true;
+ if (const Type &RetT = *T->getReturnType().getTypePtr();
+ IsTopLevelAndCXXVirtualMethod && mayBeCovariant(RetT)) {
+ // Possible covariant types mangle dummy cv-unqualified `class v` as its
+ // class type
+ if (RetT.isPointerType())
+ getStream() << "P1v";
+ else if (RetT.isLValueReferenceType())
+ getStream() << "R1v";
+ else {
+ assert(RetT.isRValueReferenceType() &&
+ "Expect an r-value ref for covariant return type that is not a "
+ "pointer or an l-value ref");
+ getStream() << "O1v";
+ }
+
+ IsTopLevelAndCXXVirtualMethod = false; // Not top-level anymore
+ MangleReturnType = false;
+ }
+ mangleBareFunctionType(T, MangleReturnType);
+
+ // Mangle the ref-qualifier, if present.
+ mangleRefQualifier(T->getRefQualifier());
+
+ getStream() << 'E';
+ }
+
+ void mangleTypeImpl(const FunctionNoProtoType *T) override {
+ return CXXNameMangler::mangleTypeImpl(toFunctionProtoType(T));
+ }
+
+private:
+ const FunctionProtoType *
+ toFunctionProtoType(const FunctionNoProtoType *const T) {
+ FunctionProtoType::ExtProtoInfo EPI;
+ EPI.ExtInfo = T->getExtInfo();
+ const Type *const NewT = getASTContext()
+ .getFunctionType(T->getReturnType(), {}, EPI)
+ .getTypePtr();
+ return static_cast<const FunctionProtoType *>(NewT);
+ }
+}; // class RISCVZicfilpFuncSigLabelMangler
+
+} // anonymous namespace
+
//
/// Mangles the name of the declaration D and emits that name to the given
@@ -7412,6 +7534,17 @@ void ItaniumMangleContextImpl::mangleModuleInitializer(const Module *M,
}
}
+void ItaniumMangleContextImpl::mangleForRISCVZicfilpFuncSigLabel(
+ const FunctionType &FT, const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod, raw_ostream &Out) {
+ if (IsCXXInstanceMethod)
+ // member methods uses a dummy class named `v` in place of real classes
+ Out << "M1v";
+
+ RISCVZicfilpFuncSigLabelMangler Mangler(*this, Out, IsCXXVirtualMethod);
+ Mangler.mangleType(QualType(&FT, 0));
+}
+
ItaniumMangleContext *ItaniumMangleContext::create(ASTContext &Context,
DiagnosticsEngine &Diags,
bool IsAux) {
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 5ba098144a74e7..c7b6b56690c9ab 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2829,6 +2829,56 @@ void CodeGenModule::CreateFunctionTypeMetadataForIcall(const FunctionDecl *FD,
F->addTypeMetadata(0, llvm::ConstantAsMetadata::get(CrossDsoTypeId));
}
+uint32_t
+CodeGenModule::calcRISCVZicfilpFuncSigLabel(const FunctionType &FT,
+ const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod) {
+ std::string OutName;
+ llvm::raw_string_ostream Out(OutName);
+ MangleContext &MC = getCXXABI().getMangleContext();
+ cast<ItaniumMangleContext>(MC).mangleForRISCVZicfilpFuncSigLabel(
+ FT, IsCXXInstanceMethod, IsCXXVirtualMethod, Out);
+
+ const llvm::MD5::MD5Result MD5Result =
+ llvm::MD5::hash({(const uint8_t *)OutName.data(), OutName.size()});
+
+ // Take 20 bits of MD5 result with the approach specified by psABI
+ uint64_t MD5High = MD5Result.high();
+ uint64_t MD5Low = MD5Result.low();
+ while (MD5High && MD5Low) {
+ const uint32_t Low20Bits = MD5Low & 0xFFFFFULL;
+ if (Low20Bits)
+ return Low20Bits;
+
+ // Logical right shift MD5 result by 20 bits
+ MD5Low = (MD5High & 0xFFFFF) << 44 | MD5Low >> 20;
+ MD5High >>= 20;
+ }
+
+ return llvm::MD5Hash("RISC-V") & 0xFFFFFULL;
+}
+
+uint32_t CodeGenModule::calcRISCVZicfilpFuncSigLabel(const FunctionDecl &FD) {
+ if (FD.isMain())
+ // All main functions use `int main(int, char**)` for label calculation
+ // according to psABI spec. This value is the pre-calculated label.
+ return 0xd0639;
+
+ if (isa<CXXDestructorDecl>(FD))
+ // All destructors use `void (void*)` for label calculation according to the
+ // psABI spec. This value is the pre-calculated label.
+ return 0x639c2;
+
+ bool IsCXXInstanceMethod = false;
+ bool IsCXXVirtualMethod = false;
+ if (const auto *const MD = dyn_cast<CXXMethodDecl>(&FD)) {
+ IsCXXInstanceMethod = MD->isInstance();
+ IsCXXVirtualMethod = MD->isVirtual();
+ }
+ return calcRISCVZicfilpFuncSigLabel(*FD.getFunctionType(),
+ IsCXXInstanceMethod, IsCXXVirtualMethod);
+}
+
void CodeGenModule::setKCFIType(const FunctionDecl *FD, llvm::Function *F) {
llvm::LLVMContext &Ctx = F->getContext();
llvm::MDBuilder MDB(Ctx);
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index c58bb88035ca8a..937b7c8a11b060 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -1559,6 +1559,14 @@ class CodeGenModule : public CodeGenTypeCache {
/// Emit KCFI type identifier constants and remove unused identifiers.
void finalizeKCFITypes();
+ /// Calculate RISC-V Zicfilp func-sig scheme CFI label
+ uint32_t calcRISCVZicfilpFuncSigLabel(const FunctionType &FT,
+ const bool IsCXXInstanceMethod,
+ const bool IsCXXVirtualMethod);
+
+ /// Calculate RISC-V Zicfilp func-sig scheme CFI label
+ uint32_t calcRISCVZicfilpFuncSigLabel(const FunctionDecl &FD);
+
/// Whether this function's return type has no side effects, and thus may
/// be trivially discarded if it is unused.
bool MayDropFunctionReturn(const ASTContext &Context,
|
kito-cheng
reviewed
Oct 9, 2024
Comment on lines
+2833
to
+2850
| CodeGenModule::calcRISCVZicfilpFuncSigLabel(const FunctionType &FT, | ||
| const bool IsCXXInstanceMethod, | ||
| const bool IsCXXVirtualMethod) { |
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I assume this need use when we implement %lpad_hash, so this should implement under llvm folder rather than here.
There was a problem hiding this comment.
I moved just the hash part of this function to the llvm folder.
I suppose you're suggesting that the hash part needs to be moved to llvm to support implementing the %lpad_label asm operand modifier, which takes a mangled string and hash it into a 20-bit integer, so it's only the hashing part that needs to be re-located, not the whole mangling part.
Fixed.
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Update:
|
mylai-mtk
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…:Function metadata This patch emits the RISC-V Zicfilp func-sig CFI label in the metadata of generated `llvm::Function`s. It introduces CodeGenModule::calcRISCVZicfilpFuncSigLabel(), which calculates a CFI label used in the RISC-V Zicfilp func-sig CFI scheme for a given function type/declaration. The scheme, according to psABI, encodes the label based on function signature, and the rules are modified from the Itanium C++ ABI mangling rule to allow functions (callees) that are called indirectly to have the expected label as indicated by the function pointer type seen at the call site (caller).
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This method calculates a CFI label used in the RISC-V Zicfilp func-sig CFI scheme for a given function type/declaration. The scheme, according to psABI, encodes the label based on function signature, and the rules are modified from the Itanium C++ ABI mangling rule to allow functions (callees) that are called indirectly to have the expected label as indicated by the function pointer type seen at the call site (caller).
This method is a pre-requisite to enable RISC-V Zicfilp CFI with func-sig label scheme.
The implemented psABI scheme can be found at riscv-non-isa/riscv-elf-psabi-doc#434 .
Update: This PR is expanded to include emitting the RISC-V Zicfilp func-sig CFI label in the metadata of generated
llvm::Functions. The purpose is to allow testing of the mangled function signatures.