[AArch64] Add soft-float ABI

clang/include/clang/Basic/DiagnosticCommonKinds.td

@@ -356,6 +356,8 @@ def warn_target_unrecognized_env : Warning<
 def warn_knl_knm_isa_support_removed : Warning<
   "KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.">,
   InGroup<DiagGroup<"knl-knm-isa-support-removed">>;
+def err_target_unsupported_abi_with_fpu : Error<
+  "'%0' ABI is not supported with FPU">;
 
 // Source manager
 def err_cannot_open_file : Error<"cannot open file '%0': %1">, DefaultFatal;

clang/include/clang/Basic/DiagnosticFrontendKinds.td

@@ -279,6 +279,8 @@ def err_builtin_needs_feature : Error<"%0 needs target feature %1">;
 def err_function_needs_feature : Error<
   "always_inline function %1 requires target feature '%2', but would "
   "be inlined into function %0 that is compiled without support for '%2'">;
+
+let CategoryName = "Codegen ABI Check" in {
 def err_function_always_inline_attribute_mismatch : Error<
   "always_inline function %1 and its caller %0 have mismatching %2 attributes">;
 def err_function_always_inline_new_za : Error<
@@ -290,6 +292,10 @@ def warn_avx_calling_convention
       InGroup<DiagGroup<"psabi">>;
 def err_avx_calling_convention : Error<warn_avx_calling_convention.Summary>;
 
+def err_target_unsupported_type_for_abi
+    : Error<"%0 requires %1 type support, but ABI '%2' does not support it">;
+}
+
 def err_alias_to_undefined : Error<
   "%select{alias|ifunc}0 must point to a defined "
   "%select{variable or |}1function">;

clang/include/clang/Basic/DiagnosticIDs.h

@@ -276,6 +276,9 @@ class DiagnosticIDs : public RefCountedBase<DiagnosticIDs> {
   /// category.
   static bool isARCDiagnostic(unsigned DiagID);
 
+  /// Return true if a given diagnostic is a codegen-time ABI check.
+  static bool isCodegenABICheckDiagnostic(unsigned DiagID);
+
   /// Enumeration describing how the emission of a diagnostic should
   /// be treated when it occurs during C++ template argument deduction.
   enum SFINAEResponse {

clang/lib/Basic/DiagnosticIDs.cpp

@@ -855,10 +855,18 @@ bool DiagnosticIDs::isUnrecoverable(unsigned DiagID) const {
   if (isARCDiagnostic(DiagID))
     return false;
 
+  if (isCodegenABICheckDiagnostic(DiagID))
+    return false;
+
   return true;
 }
 
 bool DiagnosticIDs::isARCDiagnostic(unsigned DiagID) {
   unsigned cat = getCategoryNumberForDiag(DiagID);
   return DiagnosticIDs::getCategoryNameFromID(cat).starts_with("ARC ");
 }
+
+bool DiagnosticIDs::isCodegenABICheckDiagnostic(unsigned DiagID) {
+  unsigned cat = getCategoryNumberForDiag(DiagID);
+  return DiagnosticIDs::getCategoryNameFromID(cat) == "Codegen ABI Check";
+}

clang/lib/Basic/Targets/AArch64.cpp

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "AArch64.h"
+#include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/TargetBuiltins.h"
 #include "clang/Basic/TargetInfo.h"
@@ -199,13 +200,23 @@ AArch64TargetInfo::AArch64TargetInfo(const llvm::Triple &Triple,
 StringRef AArch64TargetInfo::getABI() const { return ABI; }
 
 bool AArch64TargetInfo::setABI(const std::string &Name) {
-  if (Name != "aapcs" && Name != "darwinpcs")
+  if (Name != "aapcs" && Name != "aapcs-soft" && Name != "darwinpcs")
     return false;
 
   ABI = Name;
   return true;
 }
 
+bool AArch64TargetInfo::validateTarget(DiagnosticsEngine &Diags) const {
+  if (hasFeature("fp") && ABI == "aapcs-soft") {
+    // aapcs-soft is not allowed for targets with an FPU, to avoid there being
+    // two incomatible ABIs.
+    Diags.Report(diag::err_target_unsupported_abi_with_fpu) << ABI;
+    return false;
+  }
+  return true;
+}
+
 bool AArch64TargetInfo::validateBranchProtection(StringRef Spec, StringRef,
                                                  BranchProtectionInfo &BPI,
                                                  StringRef &Err) const {
@@ -680,7 +691,8 @@ bool AArch64TargetInfo::hasFeature(StringRef Feature) const {
   return llvm::StringSwitch<bool>(Feature)
       .Cases("aarch64", "arm64", "arm", true)
       .Case("fmv", HasFMV)
-      .Cases("neon", "fp", "simd", FPU & NeonMode)
+      .Case("fp", FPU & FPUMode)
+      .Cases("neon", "simd", FPU & NeonMode)
       .Case("jscvt", HasJSCVT)
       .Case("fcma", HasFCMA)
       .Case("rng", HasRandGen)

clang/lib/Basic/Targets/AArch64.h

@@ -199,6 +199,8 @@ class LLVM_LIBRARY_VISIBILITY AArch64TargetInfo : public TargetInfo {
   bool hasInt128Type() const override;
 
   bool hasBitIntType() const override { return true; }
+
+  bool validateTarget(DiagnosticsEngine &Diags) const override;
 };
 
 class LLVM_LIBRARY_VISIBILITY AArch64leTargetInfo : public AArch64TargetInfo {

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -1360,6 +1360,8 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
   FunctionArgList Args;
   QualType ResTy = BuildFunctionArgList(GD, Args);
 
+  CGM.getTargetCodeGenInfo().checkFunctionABI(CGM, FD);
+
   if (FD->isInlineBuiltinDeclaration()) {
     // When generating code for a builtin with an inline declaration, use a
     // mangled name to hold the actual body, while keeping an external

clang/lib/CodeGen/CodeGenModule.cpp

@@ -145,6 +145,8 @@ createTargetCodeGenInfo(CodeGenModule &CGM) {
       Kind = AArch64ABIKind::DarwinPCS;
     else if (Triple.isOSWindows())
       return createWindowsAArch64TargetCodeGenInfo(CGM, AArch64ABIKind::Win64);
+    else if (Target.getABI() == "aapcs-soft")
+      Kind = AArch64ABIKind::AAPCSSoft;
 
     return createAArch64TargetCodeGenInfo(CGM, Kind);
   }

clang/lib/CodeGen/ModuleBuilder.cpp

@@ -180,7 +180,7 @@ namespace {
 
     bool HandleTopLevelDecl(DeclGroupRef DG) override {
       // FIXME: Why not return false and abort parsing?
-      if (Diags.hasErrorOccurred())
+      if (Diags.hasUnrecoverableErrorOccurred())
         return true;
 
       HandlingTopLevelDeclRAII HandlingDecl(*this);
@@ -206,7 +206,7 @@ namespace {
     }
 
     void HandleInlineFunctionDefinition(FunctionDecl *D) override {
-      if (Diags.hasErrorOccurred())
+      if (Diags.hasUnrecoverableErrorOccurred())
         return;
 
       assert(D->doesThisDeclarationHaveABody());
@@ -233,7 +233,7 @@ namespace {
     /// client hack on the type, which can occur at any point in the file
     /// (because these can be defined in declspecs).
     void HandleTagDeclDefinition(TagDecl *D) override {
-      if (Diags.hasErrorOccurred())
+      if (Diags.hasUnrecoverableErrorOccurred())
         return;
 
       // Don't allow re-entrant calls to CodeGen triggered by PCH
@@ -269,7 +269,7 @@ namespace {
     }
 
     void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
-      if (Diags.hasErrorOccurred())
+      if (Diags.hasUnrecoverableErrorOccurred())
         return;
 
       // Don't allow re-entrant calls to CodeGen triggered by PCH
@@ -283,7 +283,7 @@ namespace {
 
     void HandleTranslationUnit(ASTContext &Ctx) override {
       // Release the Builder when there is no error.
-      if (!Diags.hasErrorOccurred() && Builder)
+      if (!Diags.hasUnrecoverableErrorOccurred() && Builder)
         Builder->Release();
 
       // If there are errors before or when releasing the Builder, reset
@@ -297,14 +297,14 @@ namespace {
     }
 
     void AssignInheritanceModel(CXXRecordDecl *RD) override {
-      if (Diags.hasErrorOccurred())
+      if (Diags.hasUnrecoverableErrorOccurred())
         return;
 
       Builder->RefreshTypeCacheForClass(RD);
     }
 
     void CompleteTentativeDefinition(VarDecl *D) override {
-      if (Diags.hasErrorOccurred())
+      if (Diags.hasUnrecoverableErrorOccurred())
         return;
 
       Builder->EmitTentativeDefinition(D);
@@ -315,7 +315,7 @@ namespace {
     }
 
     void HandleVTable(CXXRecordDecl *RD) override {
-      if (Diags.hasErrorOccurred())
+      if (Diags.hasUnrecoverableErrorOccurred())
         return;
 
       Builder->EmitVTable(RD);

clang/lib/CodeGen/TargetInfo.h

@@ -84,6 +84,11 @@ class TargetCodeGenInfo {
   /// Provides a convenient hook to handle extra target-specific globals.
   virtual void emitTargetGlobals(CodeGen::CodeGenModule &CGM) const {}
 
+  /// Any further codegen related checks that need to be done on a function
+  /// signature in a target specific manner.
+  virtual void checkFunctionABI(CodeGenModule &CGM,
+                                const FunctionDecl *Decl) const {}
+
   /// Any further codegen related checks that need to be done on a function call
   /// in a target specific manner.
   virtual void checkFunctionCallABI(CodeGenModule &CGM, SourceLocation CallLoc,
@@ -416,6 +421,7 @@ enum class AArch64ABIKind {
   AAPCS = 0,
   DarwinPCS,
   Win64,
+  AAPCSSoft,
 };
 
 std::unique_ptr<TargetCodeGenInfo>

clang/lib/CodeGen/Targets/AArch64.cpp

@@ -27,6 +27,8 @@ class AArch64ABIInfo : public ABIInfo {
   AArch64ABIInfo(CodeGenTypes &CGT, AArch64ABIKind Kind)
       : ABIInfo(CGT), Kind(Kind) {}
 
+  bool isSoftFloat() const { return Kind == AArch64ABIKind::AAPCSSoft; }
+
 private:
   AArch64ABIKind getABIKind() const { return Kind; }
   bool isDarwinPCS() const { return Kind == AArch64ABIKind::DarwinPCS; }
@@ -55,8 +57,8 @@ class AArch64ABIInfo : public ABIInfo {
   Address EmitDarwinVAArg(Address VAListAddr, QualType Ty,
                           CodeGenFunction &CGF) const;
 
-  Address EmitAAPCSVAArg(Address VAListAddr, QualType Ty,
-                         CodeGenFunction &CGF) const;
+  Address EmitAAPCSVAArg(Address VAListAddr, QualType Ty, CodeGenFunction &CGF,
+                         AArch64ABIKind Kind) const;
 
   Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
                     QualType Ty) const override {
@@ -67,7 +69,7 @@ class AArch64ABIInfo : public ABIInfo {
 
     return Kind == AArch64ABIKind::Win64 ? EmitMSVAArg(CGF, VAListAddr, Ty)
            : isDarwinPCS()               ? EmitDarwinVAArg(VAListAddr, Ty, CGF)
-                                         : EmitAAPCSVAArg(VAListAddr, Ty, CGF);
+                           : EmitAAPCSVAArg(VAListAddr, Ty, CGF, Kind);
   }
 
   Address EmitMSVAArg(CodeGenFunction &CGF, Address VAListAddr,
@@ -163,6 +165,9 @@ class AArch64TargetCodeGenInfo : public TargetCodeGenInfo {
     return TargetCodeGenInfo::isScalarizableAsmOperand(CGF, Ty);
   }
 
+  void checkFunctionABI(CodeGenModule &CGM,
+                        const FunctionDecl *Decl) const override;
+
   void checkFunctionCallABI(CodeGenModule &CGM, SourceLocation CallLoc,
                             const FunctionDecl *Caller,
                             const FunctionDecl *Callee,
@@ -494,6 +499,11 @@ bool AArch64SwiftABIInfo::isLegalVectorType(CharUnits VectorSize,
 }
 
 bool AArch64ABIInfo::isHomogeneousAggregateBaseType(QualType Ty) const {
+  // For the soft-float ABI variant, no types are considered to be homogeneous
+  // aggregates.
+  if (Kind == AArch64ABIKind::AAPCSSoft)
+    return false;
+
   // Homogeneous aggregates for AAPCS64 must have base types of a floating
   // point type or a short-vector type. This is the same as the 32-bit ABI,
   // but with the difference that any floating-point type is allowed,
@@ -525,7 +535,8 @@ bool AArch64ABIInfo::isZeroLengthBitfieldPermittedInHomogeneousAggregate()
 }
 
 Address AArch64ABIInfo::EmitAAPCSVAArg(Address VAListAddr, QualType Ty,
-                                       CodeGenFunction &CGF) const {
+                                       CodeGenFunction &CGF,
+                                       AArch64ABIKind Kind) const {
   ABIArgInfo AI = classifyArgumentType(Ty, /*IsVariadic=*/true,
                                        CGF.CurFnInfo->getCallingConvention());
   // Empty records are ignored for parameter passing purposes.
@@ -550,7 +561,8 @@ Address AArch64ABIInfo::EmitAAPCSVAArg(Address VAListAddr, QualType Ty,
     BaseTy = ArrTy->getElementType();
     NumRegs = ArrTy->getNumElements();
   }
-  bool IsFPR = BaseTy->isFloatingPointTy() || BaseTy->isVectorTy();
+  bool IsFPR = Kind != AArch64ABIKind::AAPCSSoft &&
+               (BaseTy->isFloatingPointTy() || BaseTy->isVectorTy());
 
   // The AArch64 va_list type and handling is specified in the Procedure Call
   // Standard, section B.4:
@@ -841,6 +853,34 @@ static bool isStreamingCompatible(const FunctionDecl *F) {
   return false;
 }
 
+void AArch64TargetCodeGenInfo::checkFunctionABI(
+    CodeGenModule &CGM, const FunctionDecl *FuncDecl) const {
+  const AArch64ABIInfo &ABIInfo = getABIInfo<AArch64ABIInfo>();
+  const TargetInfo &TI = ABIInfo.getContext().getTargetInfo();
+
+  // If we are using a hard-float ABI, but do not have floating point
+  // registers, then report an error for any function arguments or returns
+  // which would be passed in floating-pint registers.
+  auto CheckType = [&CGM, &TI, &ABIInfo](const QualType &Ty,
+                                         const NamedDecl *D) {
+    const Type *HABase = nullptr;
+    uint64_t HAMembers = 0;
+    if (Ty->isFloatingType() || Ty->isVectorType() ||
+        ABIInfo.isHomogeneousAggregate(Ty, HABase, HAMembers)) {
+      CGM.getDiags().Report(D->getLocation(),
+                            diag::err_target_unsupported_type_for_abi)
+          << D->getDeclName() << Ty << TI.getABI();
+    }
+  };
+
+  if (!TI.hasFeature("fp") && !ABIInfo.isSoftFloat()) {
+    CheckType(FuncDecl->getReturnType(), FuncDecl);
+    for (ParmVarDecl *PVD : FuncDecl->parameters()) {
+      CheckType(PVD->getType(), PVD);
+    }
+  }
+}
+
 void AArch64TargetCodeGenInfo::checkFunctionCallABI(
     CodeGenModule &CGM, SourceLocation CallLoc, const FunctionDecl *Caller,
     const FunctionDecl *Callee, const CallArgList &Args) const {