[clang][bytecode] Not all null pointers are 0 (llvm#118601)

Get the Value from the ASTContext instead.

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -355,7 +355,9 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
  std::nullopt, true, false,
  /*IsMutable=*/false, nullptr);
  }
- return this->emitNull(classifyPrim(CE->getType()), Desc, CE);
+
+ uint64_t Val = Ctx.getASTContext().getTargetNullPointerValue(CE->getType());
+ return this->emitNull(classifyPrim(CE->getType()), Val, Desc, CE);
  }
 
  case CK_PointerToIntegral: {
@@ -3817,7 +3819,7 @@ template <class Emitter> bool Compiler<Emitter>::visitBool(const Expr *E) {
 
  // Convert pointers to bool.
  if (T == PT_Ptr || T == PT_FnPtr) {
- if (!this->emitNull(*T, nullptr, E))
+ if (!this->emitNull(*T, 0, nullptr, E))
  return false;
  return this->emitNE(*T, E);
  }
@@ -3857,11 +3859,12 @@ bool Compiler<Emitter>::visitZeroInitializer(PrimType T, QualType QT,
  case PT_IntAPS:
  return this->emitZeroIntAPS(Ctx.getBitWidth(QT), E);
  case PT_Ptr:
- return this->emitNullPtr(nullptr, E);
+ return this->emitNullPtr(Ctx.getASTContext().getTargetNullPointerValue(QT),
+ nullptr, E);
  case PT_FnPtr:
- return this->emitNullFnPtr(nullptr, E);
+ return this->emitNullFnPtr(0, nullptr, E);
  case PT_MemberPtr:
- return this->emitNullMemberPtr(nullptr, E);
+ return this->emitNullMemberPtr(0, nullptr, E);
  case PT_Float:
  return this->emitConstFloat(APFloat::getZero(Ctx.getFloatSemantics(QT)), E);
  case PT_FixedPoint: {
@@ -4421,7 +4424,7 @@ bool Compiler<Emitter>::visitAPValue(const APValue &Val, PrimType ValType,
 
  if (Val.isLValue()) {
  if (Val.isNullPointer())
- return this->emitNull(ValType, nullptr, E);
+ return this->emitNull(ValType, 0, nullptr, E);
  APValue::LValueBase Base = Val.getLValueBase();
  if (const Expr *BaseExpr = Base.dyn_cast<const Expr *>())
  return this->visit(BaseExpr);
@@ -4431,7 +4434,7 @@ bool Compiler<Emitter>::visitAPValue(const APValue &Val, PrimType ValType,
  } else if (Val.isMemberPointer()) {
  if (const ValueDecl *MemberDecl = Val.getMemberPointerDecl())
  return this->emitGetMemberPtr(MemberDecl, E);
- return this->emitNullMemberPtr(nullptr, E);
+ return this->emitNullMemberPtr(0, nullptr, E);
  }
 
  return false;
@@ -4783,7 +4786,8 @@ bool Compiler<Emitter>::VisitCXXNullPtrLiteralExpr(
  if (DiscardResult)
  return true;
 
- return this->emitNullPtr(nullptr, E);
+ uint64_t Val = Ctx.getASTContext().getTargetNullPointerValue(E->getType());
+ return this->emitNullPtr(Val, nullptr, E);
 }
 
 template <class Emitter>
@@ -5333,7 +5337,7 @@ bool Compiler<Emitter>::emitLambdaStaticInvokerBody(const CXXMethodDecl *MD) {
  // one here, and we don't need one either because the lambda cannot have
  // any captures, as verified above. Emit a null pointer. This is then
  // special-cased when interpreting to not emit any misleading diagnostics.
- if (!this->emitNullPtr(nullptr, MD))
+ if (!this->emitNullPtr(0, nullptr, MD))
  return false;
 
  // Forward all arguments from the static invoker to the lambda call operator.
@@ -6483,7 +6487,7 @@ bool Compiler<Emitter>::emitBuiltinBitCast(const CastExpr *E) {
  if (!this->discard(SubExpr))
  return false;
 
- return this->emitNullPtr(nullptr, E);
+ return this->emitNullPtr(0, nullptr, E);
  }
 
  if (FromType->isNullPtrType() && ToT) {

clang/lib/AST/ByteCode/Interp.h

@@ -2432,9 +2432,11 @@ static inline bool ZeroIntAPS(InterpState &S, CodePtr OpPC, uint32_t BitWidth) {
 }
 
 template <PrimType Name, class T = typename PrimConv<Name>::T>
-inline bool Null(InterpState &S, CodePtr OpPC, const Descriptor *Desc) {
- // Note: Desc can be null.
- S.Stk.push<T>(0, Desc);
+inline bool Null(InterpState &S, CodePtr OpPC, uint64_t Value,
+ const Descriptor *Desc) {
+ // FIXME(perf): This is a somewhat often-used function and the value of a
+ // null pointer is almost always 0.
+ S.Stk.push<T>(Value, Desc);
  return true;
 }
 

clang/lib/AST/ByteCode/Opcodes.td

@@ -281,7 +281,7 @@ def ZeroIntAPS : Opcode {
 // [] -> [Pointer]
 def Null : Opcode {
  let Types = [PtrTypeClass];
- let Args = [ArgDesc];
+ let Args = [ArgUint64, ArgDesc];
  let HasGroup = 1;
 }
 

clang/test/AST/ByteCode/amdgpu-nullptr.cl

@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -no-enable-noundef-analysis %s -cl-std=CL2.0 -triple amdgcn -emit-llvm -o - | FileCheck %s
+
+// RUN: %clang_cc1 -no-enable-noundef-analysis %s -cl-std=CL2.0 -triple amdgcn -emit-llvm -fexperimental-new-constant-interpreter -o - | FileCheck %s
+
+
+// CHECK: @fold_priv ={{.*}} local_unnamed_addr addrspace(1) global ptr addrspace(5) addrspacecast (ptr addrspace(1) null to ptr addrspace(5)), align 4
+private short *fold_priv = (private short*)(generic int*)(global void*)0;
+
+// CHECK: @fold_priv_arith ={{.*}} local_unnamed_addr addrspace(1) global ptr addrspace(5) inttoptr (i32 9 to ptr addrspace(5)), align 4
+private char *fold_priv_arith = (private char*)0 + 10;
+
+