[Clang][CodeGen] Move EmitPointerArithmetic into CodeGenFunction. NFC. (#152634)

`CodeGenFunction::EmitPointerArithmetic` is needed by
llvm/llvm-project#152575. Separate the NFC
changes into a new PR for smooth review.

Author: dtcxzyw

clang/lib/CodeGen/CGExprScalar.cpp

@@ -4183,9 +4183,8 @@ Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) {
   return phi;
 }
 
-/// Emit pointer + index arithmetic.
-static Value *emitPointerArithmetic(CodeGenFunction &CGF,
-                                    const BinOpInfo &op,
+/// This function is used for BO_Add/BO_Sub/BO_AddAssign/BO_SubAssign.
+static Value *emitPointerArithmetic(CodeGenFunction &CGF, const BinOpInfo &op,
                                     bool isSubtraction) {
   // Must have binary (not unary) expr here.  Unary pointer
   // increment/decrement doesn't use this path.
@@ -4202,11 +4201,19 @@ static Value *emitPointerArithmetic(CodeGenFunction &CGF,
     std::swap(pointerOperand, indexOperand);
   }
 
+  return CGF.EmitPointerArithmetic(expr, pointerOperand, pointer, indexOperand,
+                                   index, isSubtraction);
+}
+
+/// Emit pointer + index arithmetic.
+llvm::Value *CodeGenFunction::EmitPointerArithmetic(
+    const BinaryOperator *BO, Expr *pointerOperand, llvm::Value *pointer,
+    Expr *indexOperand, llvm::Value *index, bool isSubtraction) {
   bool isSigned = indexOperand->getType()->isSignedIntegerOrEnumerationType();
 
   unsigned width = cast<llvm::IntegerType>(index->getType())->getBitWidth();
-  auto &DL = CGF.CGM.getDataLayout();
-  auto PtrTy = cast<llvm::PointerType>(pointer->getType());
+  auto &DL = CGM.getDataLayout();
+  auto *PtrTy = cast<llvm::PointerType>(pointer->getType());
 
   // Some versions of glibc and gcc use idioms (particularly in their malloc
   // routines) that add a pointer-sized integer (known to be a pointer value)
@@ -4227,79 +4234,77 @@ static Value *emitPointerArithmetic(CodeGenFunction &CGF,
   //
   // Note that we do not suppress the pointer overflow check in this case.
   if (BinaryOperator::isNullPointerArithmeticExtension(
-          CGF.getContext(), op.Opcode, expr->getLHS(), expr->getRHS())) {
-    Value *Ptr = CGF.Builder.CreateIntToPtr(index, pointer->getType());
-    if (CGF.getLangOpts().PointerOverflowDefined ||
-        !CGF.SanOpts.has(SanitizerKind::PointerOverflow) ||
-        NullPointerIsDefined(CGF.Builder.GetInsertBlock()->getParent(),
+          getContext(), BO->getOpcode(), pointerOperand, indexOperand)) {
+    llvm::Value *Ptr = Builder.CreateIntToPtr(index, pointer->getType());
+    if (getLangOpts().PointerOverflowDefined ||
+        !SanOpts.has(SanitizerKind::PointerOverflow) ||
+        NullPointerIsDefined(Builder.GetInsertBlock()->getParent(),
                              PtrTy->getPointerAddressSpace()))
       return Ptr;
     // The inbounds GEP of null is valid iff the index is zero.
     auto CheckOrdinal = SanitizerKind::SO_PointerOverflow;
     auto CheckHandler = SanitizerHandler::PointerOverflow;
-    SanitizerDebugLocation SanScope(&CGF, {CheckOrdinal}, CheckHandler);
-    Value *IsZeroIndex = CGF.Builder.CreateIsNull(index);
-    llvm::Constant *StaticArgs[] = {
-        CGF.EmitCheckSourceLocation(op.E->getExprLoc())};
+    SanitizerDebugLocation SanScope(this, {CheckOrdinal}, CheckHandler);
+    llvm::Value *IsZeroIndex = Builder.CreateIsNull(index);
+    llvm::Constant *StaticArgs[] = {EmitCheckSourceLocation(BO->getExprLoc())};
     llvm::Type *IntPtrTy = DL.getIntPtrType(PtrTy);
-    Value *IntPtr = llvm::Constant::getNullValue(IntPtrTy);
-    Value *ComputedGEP = CGF.Builder.CreateZExtOrTrunc(index, IntPtrTy);
-    Value *DynamicArgs[] = {IntPtr, ComputedGEP};
-    CGF.EmitCheck({{IsZeroIndex, CheckOrdinal}}, CheckHandler, StaticArgs,
-                  DynamicArgs);
+    llvm::Value *IntPtr = llvm::Constant::getNullValue(IntPtrTy);
+    llvm::Value *ComputedGEP = Builder.CreateZExtOrTrunc(index, IntPtrTy);
+    llvm::Value *DynamicArgs[] = {IntPtr, ComputedGEP};
+    EmitCheck({{IsZeroIndex, CheckOrdinal}}, CheckHandler, StaticArgs,
+              DynamicArgs);
     return Ptr;
   }
 
   if (width != DL.getIndexTypeSizeInBits(PtrTy)) {
     // Zero-extend or sign-extend the pointer value according to
     // whether the index is signed or not.
-    index = CGF.Builder.CreateIntCast(index, DL.getIndexType(PtrTy), isSigned,
-                                      "idx.ext");
+    index = Builder.CreateIntCast(index, DL.getIndexType(PtrTy), isSigned,
+                                  "idx.ext");
   }
 
   // If this is subtraction, negate the index.
   if (isSubtraction)
-    index = CGF.Builder.CreateNeg(index, "idx.neg");
+    index = Builder.CreateNeg(index, "idx.neg");
 
-  if (CGF.SanOpts.has(SanitizerKind::ArrayBounds))
-    CGF.EmitBoundsCheck(op.E, pointerOperand, index, indexOperand->getType(),
-                        /*Accessed*/ false);
+  if (SanOpts.has(SanitizerKind::ArrayBounds))
+    EmitBoundsCheck(BO, pointerOperand, index, indexOperand->getType(),
+                    /*Accessed*/ false);
 
-  const PointerType *pointerType
-    = pointerOperand->getType()->getAs<PointerType>();
+  const PointerType *pointerType =
+      pointerOperand->getType()->getAs<PointerType>();
   if (!pointerType) {
     QualType objectType = pointerOperand->getType()
-                                        ->castAs<ObjCObjectPointerType>()
-                                        ->getPointeeType();
-    llvm::Value *objectSize
-      = CGF.CGM.getSize(CGF.getContext().getTypeSizeInChars(objectType));
+                              ->castAs<ObjCObjectPointerType>()
+                              ->getPointeeType();
+    llvm::Value *objectSize =
+        CGM.getSize(getContext().getTypeSizeInChars(objectType));
 
-    index = CGF.Builder.CreateMul(index, objectSize);
+    index = Builder.CreateMul(index, objectSize);
 
-    Value *result =
-        CGF.Builder.CreateGEP(CGF.Int8Ty, pointer, index, "add.ptr");
-    return CGF.Builder.CreateBitCast(result, pointer->getType());
+    llvm::Value *result = Builder.CreateGEP(Int8Ty, pointer, index, "add.ptr");
+    return Builder.CreateBitCast(result, pointer->getType());
   }
 
   QualType elementType = pointerType->getPointeeType();
-  if (const VariableArrayType *vla
-        = CGF.getContext().getAsVariableArrayType(elementType)) {
+  if (const VariableArrayType *vla =
+          getContext().getAsVariableArrayType(elementType)) {
     // The element count here is the total number of non-VLA elements.
-    llvm::Value *numElements = CGF.getVLASize(vla).NumElts;
+    llvm::Value *numElements = getVLASize(vla).NumElts;
 
     // Effectively, the multiply by the VLA size is part of the GEP.
     // GEP indexes are signed, and scaling an index isn't permitted to
     // signed-overflow, so we use the same semantics for our explicit
     // multiply.  We suppress this if overflow is not undefined behavior.
-    llvm::Type *elemTy = CGF.ConvertTypeForMem(vla->getElementType());
-    if (CGF.getLangOpts().PointerOverflowDefined) {
-      index = CGF.Builder.CreateMul(index, numElements, "vla.index");
-      pointer = CGF.Builder.CreateGEP(elemTy, pointer, index, "add.ptr");
+    llvm::Type *elemTy = ConvertTypeForMem(vla->getElementType());
+    if (getLangOpts().PointerOverflowDefined) {
+      index = Builder.CreateMul(index, numElements, "vla.index");
+      pointer = Builder.CreateGEP(elemTy, pointer, index, "add.ptr");
     } else {
-      index = CGF.Builder.CreateNSWMul(index, numElements, "vla.index");
-      pointer = CGF.EmitCheckedInBoundsGEP(
-          elemTy, pointer, index, isSigned, isSubtraction, op.E->getExprLoc(),
-          "add.ptr");
+      index = Builder.CreateNSWMul(index, numElements, "vla.index");
+      pointer =
+          EmitCheckedInBoundsGEP(elemTy, pointer, index, isSigned,
+                                 isSubtraction, BO->getExprLoc(), "add.ptr");
     }
     return pointer;
   }
@@ -4309,16 +4314,15 @@ static Value *emitPointerArithmetic(CodeGenFunction &CGF,
   // future proof.
   llvm::Type *elemTy;
   if (elementType->isVoidType() || elementType->isFunctionType())
-    elemTy = CGF.Int8Ty;
+    elemTy = Int8Ty;
   else
-    elemTy = CGF.ConvertTypeForMem(elementType);
+    elemTy = ConvertTypeForMem(elementType);
 
-  if (CGF.getLangOpts().PointerOverflowDefined)
-    return CGF.Builder.CreateGEP(elemTy, pointer, index, "add.ptr");
+  if (getLangOpts().PointerOverflowDefined)
+    return Builder.CreateGEP(elemTy, pointer, index, "add.ptr");
 
-  return CGF.EmitCheckedInBoundsGEP(
-      elemTy, pointer, index, isSigned, isSubtraction, op.E->getExprLoc(),
-      "add.ptr");
+  return EmitCheckedInBoundsGEP(elemTy, pointer, index, isSigned, isSubtraction,
+                                BO->getExprLoc(), "add.ptr");
 }
 
 // Construct an fmuladd intrinsic to represent a fused mul-add of MulOp and

clang/lib/CodeGen/CodeGenFunction.h

@@ -5212,6 +5212,12 @@ class CodeGenFunction : public CodeGenTypeCache {
   /// operation is a subtraction.
   enum { NotSubtraction = false, IsSubtraction = true };
 
+  /// Emit pointer + index arithmetic.
+  llvm::Value *EmitPointerArithmetic(const BinaryOperator *BO,
+                                     Expr *pointerOperand, llvm::Value *pointer,
+                                     Expr *indexOperand, llvm::Value *index,
+                                     bool isSubtraction);
+
   /// Same as IRBuilder::CreateInBoundsGEP, but additionally emits a check to
   /// detect undefined behavior when the pointer overflow sanitizer is enabled.
   /// \p SignedIndices indicates whether any of the GEP indices are signed.