Revert "[CIR][ABI] Apply CC lowering pass by default (#842)"

Fix #895 and it's also missing some more
throughout behavior for the pass, it also needs to be enabled by default when
emitting object files.

This reverts commit db6b7c0.

Author: bcardosolopes

clang/include/clang/CIR/Dialect/Passes.h

@@ -42,7 +42,7 @@ std::unique_ptr<Pass> createGotoSolverPass();
 /// Create a pass to lower ABI-independent function definitions/calls.
 std::unique_ptr<Pass> createCallConvLoweringPass();
 
-void populateCIRPreLoweringPasses(mlir::OpPassManager &pm, bool useCCLowering);
+void populateCIRPreLoweringPasses(mlir::OpPassManager &pm);
 
 //===----------------------------------------------------------------------===//
 // Registration

clang/include/clang/CIR/MissingFeatures.h

@@ -15,27 +15,6 @@
 #ifndef CLANG_CIR_MISSINGFEATURES_H
 #define CLANG_CIR_MISSINGFEATURES_H
 
-constexpr bool cirMissingFeatureAssertionMode =
-    true; // Change to `false` to use llvm_unreachable
-
-#define NOTE                                                                   \
-  " Target lowering is now required. Disable it with "                         \
-  "-fno-clangir-call-conv-lowering."
-
-// Special assertion to be used in the target lowering library.
-#define cir_tl_assert(cond) assert((cond) && NOTE);
-
-// Some assertions knowingly generate incorrect code. This macro allows us to
-// switch between using `assert` and `llvm_unreachable` for these cases.
-#define cir_assert_or_abort(cond, msg)                                         \
-  do {                                                                         \
-    if (cirMissingFeatureAssertionMode) {                                      \
-      assert((cond) && msg NOTE);                                              \
-    } else {                                                                   \
-      llvm_unreachable(msg NOTE);                                              \
-    }                                                                          \
-  } while (0)
-
 namespace cir {
 
 struct MissingFeatures {
@@ -233,26 +212,6 @@ struct MissingFeatures {
 
   //===--- ABI lowering --===//
 
-  static bool SPIRVABI() { return false; }
-
-  static bool AArch64TypeClassification() { return false; }
-
-  static bool X86ArgTypeClassification() { return false; }
-  static bool X86DefaultABITypeConvertion() { return false; }
-  static bool X86GetFPTypeAtOffset() { return false; }
-  static bool X86RetTypeClassification() { return false; }
-  static bool X86TypeClassification() { return false; }
-
-  static bool ABIClangTypeKind() { return false; }
-  static bool ABIEnterStructForCoercedAccess() { return false; }
-  static bool ABIFuncPtr() { return false; }
-  static bool ABIInRegAttribute() { return false; }
-  static bool ABINestedRecordLayout() { return false; }
-  static bool ABINoProtoFunctions() { return false; }
-  static bool ABIParameterCoercion() { return false; }
-  static bool ABIPointerParameterAttrs() { return false; }
-  static bool ABITransparentUnionHandling() { return false; }
-
   //-- Missing AST queries
 
   static bool CXXRecordDeclIsEmptyCXX11() { return false; }

clang/include/clang/Driver/Options.td

@@ -2978,6 +2978,10 @@ def fclangir_lib_opt : Flag<["-"], "fclangir-lib-opt">,
   Visibility<[ClangOption, CC1Option]>, Group<f_Group>,
   Alias<fclangir_lib_opt_EQ>,
   HelpText<"Enable C/C++ library based optimizations">;
+def fclangir_call_conv_lowering : Flag<["-"], "fclangir-call-conv-lowering">,
+  Visibility<[ClangOption, CC1Option]>, Group<f_Group>,
+  HelpText<"Enable ClangIR calling convention lowering">,
+  MarshallingInfoFlag<FrontendOpts<"ClangIREnableCallConvLowering">>;
 def fclangir_mem2reg : Flag<["-"], "fclangir-mem2reg">,
   Visibility<[ClangOption, CC1Option]>, Group<f_Group>,
   HelpText<"Enable mem2reg on the flat ClangIR">,
@@ -3008,13 +3012,6 @@ defm clangir_analysis_only : BoolFOption<"clangir-analysis-only",
   PosFlag<SetTrue, [], [ClangOption, CC1Option],
     "Enable CIR analysis but keep traditional LLVM codegen (not through CIR)">,
   NegFlag<SetFalse, [], [ClangOption, CC1Option],  "">>;
-// FIXME(cir): Remove this option once all pre-existing tests are compatible with
-// the calling convention lowering pass.
-defm clangir_call_conv_lowering : BoolFOption<"clangir-call-conv-lowering",
-  FrontendOpts<"ClangIRCallConvLowering">, DefaultTrue,
-  PosFlag<SetTrue, [], [ClangOption, CC1Option], "Transform CIR to abide to calling convetions during lowering">,
-  NegFlag<SetFalse, [], [ClangOption, CC1Option], "Ignore calling convetion during lowering">,
-  BothFlags<[], [ClangOption, CC1Option], "">>;
 
 def emit_cir : Flag<["-"], "emit-cir">, Visibility<[CC1Option]>,
   Group<Action_Group>, HelpText<"Build ASTs and then lower to ClangIR, emit the .cir file">;

clang/include/clang/Frontend/FrontendOptions.h

@@ -445,7 +445,7 @@ class FrontendOptions {
   unsigned ClangIRLibOpt : 1;
 
   // Enable Clang IR call conv lowering pass.
-  unsigned ClangIRCallConvLowering : 1;
+  unsigned ClangIREnableCallConvLowering : 1;
 
   // Enable Clang IR mem2reg pass on the flat CIR.
   unsigned ClangIREnableMem2Reg : 1;

clang/lib/CIR/CodeGen/CIRPasses.cpp

@@ -71,8 +71,13 @@ mlir::LogicalResult runCIRToCIRPasses(
 
   pm.addPass(mlir::createLoweringPreparePass(&astCtx));
 
+  // FIXME(cir): This pass should run by default, but it is lacking support for
+  // several code bits. Once it's more mature, we should fix this.
+  if (enableCallConvLowering)
+    pm.addPass(mlir::createCallConvLoweringPass());
+
   if (flattenCIR || enableMem2Reg)
-    mlir::populateCIRPreLoweringPasses(pm, enableCallConvLowering);
+    mlir::populateCIRPreLoweringPasses(pm);
 
   if (enableMem2Reg)
     pm.addPass(mlir::createMem2Reg());
@@ -92,9 +97,7 @@ mlir::LogicalResult runCIRToCIRPasses(
 
 namespace mlir {
 
-void populateCIRPreLoweringPasses(OpPassManager &pm, bool useCCLowering) {
-  if (useCCLowering)
-    pm.addPass(createCallConvLoweringPass());
+void populateCIRPreLoweringPasses(OpPassManager &pm) {
   pm.addPass(createFlattenCFGPass());
   pm.addPass(createGotoSolverPass());
 }

clang/lib/CIR/Dialect/Transforms/CallConvLowering.cpp

@@ -6,14 +6,14 @@
 //
 //===----------------------------------------------------------------------===//
 
+
 #include "TargetLowering/LowerModule.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/IR/BuiltinOps.h"
 #include "mlir/IR/PatternMatch.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
 #include "clang/CIR/Dialect/IR/CIRDialect.h"
-#include "clang/CIR/MissingFeatures.h"
 
 #define GEN_PASS_DEF_CALLCONVLOWERING
 #include "clang/CIR/Dialect/Passes.h.inc"
@@ -44,12 +44,6 @@ struct CallConvLoweringPattern : public OpRewritePattern<FuncOp> {
     auto calls = op.getSymbolUses(module);
     if (calls.has_value()) {
       for (auto call : calls.value()) {
-        // FIXME(cir): Function pointers are ignored.
-        if (isa<GetGlobalOp>(call.getUser())) {
-          cir_assert_or_abort(!::cir::MissingFeatures::ABIFuncPtr(), "NYI");
-          continue;
-        }
-
         auto callOp = cast<CallOp>(call.getUser());
         if (lowerModule->rewriteFunctionCall(callOp, op).failed())
           return failure();

clang/lib/CIR/Dialect/Transforms/TargetLowering/ABIInfo.cpp

@@ -37,7 +37,7 @@ bool ABIInfo::isPromotableIntegerTypeForABI(Type Ty) const {
   if (getContext().isPromotableIntegerType(Ty))
     return true;
 
-  cir_tl_assert(!::cir::MissingFeatures::fixedWidthIntegers());
+  assert(!::cir::MissingFeatures::fixedWidthIntegers());
 
   return false;
 }

clang/lib/CIR/Dialect/Transforms/TargetLowering/ABIInfoImpl.cpp

@@ -26,22 +26,21 @@ bool classifyReturnType(const CIRCXXABI &CXXABI, LowerFunctionInfo &FI,
   Type Ty = FI.getReturnType();
 
   if (const auto RT = dyn_cast<StructType>(Ty)) {
-    cir_tl_assert(!::cir::MissingFeatures::isCXXRecordDecl());
+    assert(!::cir::MissingFeatures::isCXXRecordDecl());
   }
 
   return CXXABI.classifyReturnType(FI);
 }
 
 bool isAggregateTypeForABI(Type T) {
-  cir_tl_assert(!::cir::MissingFeatures::functionMemberPointerType());
+  assert(!::cir::MissingFeatures::functionMemberPointerType());
   return !LowerFunction::hasScalarEvaluationKind(T);
 }
 
 Type useFirstFieldIfTransparentUnion(Type Ty) {
   if (auto RT = dyn_cast<StructType>(Ty)) {
     if (RT.isUnion())
-      cir_assert_or_abort(
-          !::cir::MissingFeatures::ABITransparentUnionHandling(), "NYI");
+      llvm_unreachable("NYI");
   }
   return Ty;
 }

clang/lib/CIR/Dialect/Transforms/TargetLowering/CIRLowerContext.cpp

@@ -55,10 +55,7 @@ clang::TypeInfo CIRLowerContext::getTypeInfoImpl(const Type T) const {
   } else if (isa<StructType>(T)) {
     typeKind = clang::Type::Record;
   } else {
-    cir_assert_or_abort(!::cir::MissingFeatures::ABIClangTypeKind(),
-                        "Unhandled type class");
-    // FIXME(cir): Completely wrong. Just here to make it non-blocking.
-    typeKind = clang::Type::Builtin;
+    llvm_unreachable("Unhandled type class");
   }
 
   // FIXME(cir): Here we fetch the width and alignment of a type considering the
@@ -99,10 +96,10 @@ clang::TypeInfo CIRLowerContext::getTypeInfoImpl(const Type T) const {
   }
   case clang::Type::Record: {
     const auto RT = dyn_cast<StructType>(T);
-    cir_tl_assert(!::cir::MissingFeatures::tagTypeClassAbstraction());
+    assert(!::cir::MissingFeatures::tagTypeClassAbstraction());
 
     // Only handle TagTypes (names types) for now.
-    cir_tl_assert(RT.getName() && "Anonymous record is NYI");
+    assert(RT.getName() && "Anonymous record is NYI");
 
     // NOTE(cir): Clang does some hanlding of invalid tagged declarations here.
     // Not sure if this is necessary in CIR.
@@ -114,22 +111,22 @@ clang::TypeInfo CIRLowerContext::getTypeInfoImpl(const Type T) const {
     const CIRRecordLayout &Layout = getCIRRecordLayout(RT);
     Width = toBits(Layout.getSize());
     Align = toBits(Layout.getAlignment());
-    cir_tl_assert(!::cir::MissingFeatures::recordDeclHasAlignmentAttr());
+    assert(!::cir::MissingFeatures::recordDeclHasAlignmentAttr());
     break;
   }
   default:
     llvm_unreachable("Unhandled type class");
   }
 
-  cir_tl_assert(llvm::isPowerOf2_32(Align) && "Alignment must be power of 2");
+  assert(llvm::isPowerOf2_32(Align) && "Alignment must be power of 2");
   return clang::TypeInfo(Width, Align, AlignRequirement);
 }
 
 Type CIRLowerContext::initBuiltinType(clang::BuiltinType::Kind K) {
   Type Ty;
 
   // NOTE(cir): Clang does more stuff here. Not sure if we need to do the same.
-  cir_tl_assert(!::cir::MissingFeatures::qualifiedTypes());
+  assert(!::cir::MissingFeatures::qualifiedTypes());
   switch (K) {
   case clang::BuiltinType::Char_S:
     Ty = IntType::get(getMLIRContext(), 8, true);
@@ -144,7 +141,7 @@ Type CIRLowerContext::initBuiltinType(clang::BuiltinType::Kind K) {
 
 void CIRLowerContext::initBuiltinTypes(const clang::TargetInfo &Target,
                                        const clang::TargetInfo *AuxTarget) {
-  cir_tl_assert((!this->Target || this->Target == &Target) &&
+  assert((!this->Target || this->Target == &Target) &&
          "Incorrect target reinitialization");
   this->Target = &Target;
   this->AuxTarget = AuxTarget;

clang/lib/CIR/Dialect/Transforms/TargetLowering/CIRRecordLayout.cpp

@@ -38,16 +38,16 @@ CIRRecordLayout::CIRRecordLayout(
   FieldOffsets.insert(FieldOffsets.end(), fieldoffsets.begin(),
                       fieldoffsets.end());
 
-  cir_tl_assert(!PrimaryBase && "Layout for class with inheritance is NYI");
+  assert(!PrimaryBase && "Layout for class with inheritance is NYI");
   // CXXInfo->PrimaryBase.setPointer(PrimaryBase);
-  cir_tl_assert(!IsPrimaryBaseVirtual && "Layout for virtual base class is NYI");
+  assert(!IsPrimaryBaseVirtual && "Layout for virtual base class is NYI");
   // CXXInfo->PrimaryBase.setInt(IsPrimaryBaseVirtual);
   CXXInfo->NonVirtualSize = nonvirtualsize;
   CXXInfo->NonVirtualAlignment = nonvirtualalignment;
   CXXInfo->PreferredNVAlignment = preferrednvalignment;
   CXXInfo->SizeOfLargestEmptySubobject = SizeOfLargestEmptySubobject;
   // FIXME(cir): Initialize base classes offsets.
-  cir_tl_assert(!::cir::MissingFeatures::getCXXRecordBases());
+  assert(!::cir::MissingFeatures::getCXXRecordBases());
   CXXInfo->HasOwnVFPtr = hasOwnVFPtr;
   CXXInfo->VBPtrOffset = vbptroffset;
   CXXInfo->HasExtendableVFPtr = hasExtendableVFPtr;