all: remove pointer ElementType calls

This is needed for opaque pointers, which are enabled by default in
LLVM 15.

compiler/asserts.go

@@ -91,7 +91,7 @@ func (b *builder) createSliceToArrayPointerCheck(sliceLen llvm.Value, arrayLen i
 
 // createUnsafeSliceCheck inserts a runtime check used for unsafe.Slice. This
 // function must panic if the ptr/len parameters are invalid.
-func (b *builder) createUnsafeSliceCheck(ptr, len llvm.Value, lenType *types.Basic) {
+func (b *builder) createUnsafeSliceCheck(ptr, len llvm.Value, elementType llvm.Type, lenType *types.Basic) {
 	// From the documentation of unsafe.Slice:
 	//   > At run time, if len is negative, or if ptr is nil and len is not
 	//   > zero, a run-time panic occurs.
@@ -105,7 +105,7 @@ func (b *builder) createUnsafeSliceCheck(ptr, len llvm.Value, lenType *types.Bas
 
 	// Determine the maximum slice size, and therefore the maximum value of the
 	// len parameter.
-	maxSize := b.maxSliceSize(ptr.Type().ElementType())
+	maxSize := b.maxSliceSize(elementType)
 	maxSizeValue := llvm.ConstInt(len.Type(), maxSize, false)
 
 	// Do the check. By using unsigned greater than for the length check, signed

compiler/calls.go

@@ -20,7 +20,7 @@ const maxFieldsPerParam = 3
 type paramInfo struct {
 	llvmType llvm.Type
 	name     string // name, possibly with suffixes for e.g. struct fields
-	flags    paramFlags
+	elemSize uint64 // size of pointer element type, or 0 if this isn't a pointer
 }
 
 // paramFlags identifies parameter attributes for flags. Most importantly, it
@@ -96,13 +96,7 @@ func (c *compilerContext) expandFormalParamType(t llvm.Type, name string, goType
 		// failed to expand this parameter: too many fields
 	}
 	// TODO: split small arrays
-	return []paramInfo{
-		{
-			llvmType: t,
-			name:     name,
-			flags:    getTypeFlags(goType),
-		},
-	}
+	return []paramInfo{c.getParamInfo(t, name, goType)}
 }
 
 // expandFormalParamOffsets returns a list of offsets from the start of an
@@ -152,7 +146,6 @@ func (b *builder) expandFormalParam(v llvm.Value) []llvm.Value {
 // Try to flatten a struct type to a list of types. Returns a 1-element slice
 // with the passed in type if this is not possible.
 func (c *compilerContext) flattenAggregateType(t llvm.Type, name string, goType types.Type) []paramInfo {
-	typeFlags := getTypeFlags(goType)
 	switch t.TypeKind() {
 	case llvm.StructTypeKind:
 		var paramInfos []paramInfo
@@ -183,40 +176,37 @@ func (c *compilerContext) flattenAggregateType(t llvm.Type, name string, goType
 				}
 			}
 			subInfos := c.flattenAggregateType(subfield, name+"."+suffix, extractSubfield(goType, i))
-			for i := range subInfos {
-				subInfos[i].flags |= typeFlags
-			}
 			paramInfos = append(paramInfos, subInfos...)
 		}
 		return paramInfos
 	default:
-		return []paramInfo{
-			{
-				llvmType: t,
-				name:     name,
-				flags:    typeFlags,
-			},
-		}
+		return []paramInfo{c.getParamInfo(t, name, goType)}
 	}
 }
 
-// getTypeFlags returns the type flags for a given type. It will not recurse
-// into sub-types (such as in structs).
-func getTypeFlags(t types.Type) paramFlags {
-	if t == nil {
-		return 0
+// getParamInfo collects information about a parameter. For example, if this
+// parameter is pointer-like, it will also store the element type for the
+// dereferenceable_or_null attribute.
+func (c *compilerContext) getParamInfo(t llvm.Type, name string, goType types.Type) paramInfo {
+	info := paramInfo{
+		llvmType: t,
+		name:     name,
 	}
-	switch t.Underlying().(type) {
-	case *types.Pointer:
-		// Pointers in Go must either point to an object or be nil.
-		return paramIsDeferenceableOrNull
-	case *types.Chan, *types.Map:
-		// Channels and maps are implemented as pointers pointing to some
-		// object, and follow the same rules as *types.Pointer.
-		return paramIsDeferenceableOrNull
-	default:
-		return 0
+	if goType != nil {
+		switch underlying := goType.Underlying().(type) {
+		case *types.Pointer:
+			// Pointers in Go must either point to an object or be nil.
+			info.elemSize = c.targetData.TypeAllocSize(c.getLLVMType(underlying.Elem()))
+		case *types.Chan:
+			// Channels are implemented simply as a *runtime.channel.
+			info.elemSize = c.targetData.TypeAllocSize(c.getLLVMRuntimeType("channel"))
+		case *types.Map:
+			// Maps are similar to channels: they are implemented as a
+			// *runtime.hashmap.
+			info.elemSize = c.targetData.TypeAllocSize(c.getLLVMRuntimeType("hashmap"))
+		}
 	}
+	return info
 }
 
 // extractSubfield extracts a field from a struct, or returns null if this is

compiler/compiler.go

@@ -862,7 +862,7 @@ func (c *compilerContext) createPackage(irbuilder llvm.Builder, pkg *ssa.Package
 			if files, ok := c.embedGlobals[member.Name()]; ok {
 				c.createEmbedGlobal(member, global, files)
 			} else if !info.extern {
-				global.SetInitializer(llvm.ConstNull(global.Type().ElementType()))
+				global.SetInitializer(llvm.ConstNull(global.GlobalValueType()))
 				global.SetVisibility(llvm.HiddenVisibility)
 				if info.section != "" {
 					global.SetSection(info.section)
@@ -1405,7 +1405,7 @@ func (b *builder) createInstruction(instr ssa.Instruction) {
 			b.CreateRet(b.getValue(instr.Results[0]))
 		} else {
 			// Multiple return values. Put them all in a struct.
-			retVal := llvm.ConstNull(b.llvmFn.Type().ElementType().ReturnType())
+			retVal := llvm.ConstNull(b.llvmFn.GlobalValueType().ReturnType())
 			for i, result := range instr.Results {
 				val := b.getValue(result)
 				retVal = b.CreateInsertValue(retVal, val, i, "")
@@ -1444,7 +1444,7 @@ func (b *builder) createBuiltin(argTypes []types.Type, argValues []llvm.Value, c
 		elemsBuf := b.CreateExtractValue(elems, 0, "append.elemsBuf")
 		elemsPtr := b.CreateBitCast(elemsBuf, b.i8ptrType, "append.srcPtr")
 		elemsLen := b.CreateExtractValue(elems, 1, "append.elemsLen")
-		elemType := srcBuf.Type().ElementType()
+		elemType := b.getLLVMType(argTypes[0].Underlying().(*types.Slice).Elem())
 		elemSize := llvm.ConstInt(b.uintptrType, b.targetData.TypeAllocSize(elemType), false)
 		result := b.createRuntimeCall("sliceAppend", []llvm.Value{srcPtr, elemsPtr, srcLen, srcCap, elemsLen, elemSize}, "append.new")
 		newPtr := b.CreateExtractValue(result, 0, "append.newPtr")
@@ -1497,7 +1497,7 @@ func (b *builder) createBuiltin(argTypes []types.Type, argValues []llvm.Value, c
 		srcLen := b.CreateExtractValue(src, 1, "copy.srcLen")
 		dstBuf := b.CreateExtractValue(dst, 0, "copy.dstArray")
 		srcBuf := b.CreateExtractValue(src, 0, "copy.srcArray")
-		elemType := dstBuf.Type().ElementType()
+		elemType := b.getLLVMType(argTypes[0].Underlying().(*types.Slice).Elem())
 		dstBuf = b.CreateBitCast(dstBuf, b.i8ptrType, "copy.dstPtr")
 		srcBuf = b.CreateBitCast(srcBuf, b.i8ptrType, "copy.srcPtr")
 		elemSize := llvm.ConstInt(b.uintptrType, b.targetData.TypeAllocSize(elemType), false)
@@ -1637,7 +1637,8 @@ func (b *builder) createBuiltin(argTypes []types.Type, argValues []llvm.Value, c
 			b.uintptrType,
 			b.uintptrType,
 		}, false))
-		b.createUnsafeSliceCheck(ptr, len, argTypes[1].Underlying().(*types.Basic))
+		elementType := b.getLLVMType(argTypes[0].Underlying().(*types.Pointer).Elem())
+		b.createUnsafeSliceCheck(ptr, len, elementType, argTypes[1].Underlying().(*types.Basic))
 		if len.Type().IntTypeWidth() < b.uintptrType.IntTypeWidth() {
 			// Too small, zero-extend len.
 			len = b.CreateZExt(len, b.uintptrType, "")
@@ -1712,7 +1713,7 @@ func (b *builder) createFunctionCall(instr *ssa.CallCommon) (llvm.Value, error)
 				// Eventually we might be able to eliminate this special case
 				// entirely. For details, see:
 				// https://discourse.llvm.org/t/rfc-enabling-wstrict-prototypes-by-default-in-c/60521
-				calleeType = llvm.FunctionType(callee.Type().ElementType().ReturnType(), nil, false)
+				calleeType = llvm.FunctionType(callee.GlobalValueType().ReturnType(), nil, false)
 				callee = llvm.ConstBitCast(callee, llvm.PointerType(calleeType, b.funcPtrAddrSpace))
 			}
 		case *ssa.MakeClosure:
@@ -3095,7 +3096,7 @@ func (b *builder) createUnOp(unop *ssa.UnOp) (llvm.Value, error) {
 		}
 	case token.MUL: // *x, dereference pointer
 		valueType := b.getLLVMType(unop.X.Type().Underlying().(*types.Pointer).Elem())
-		if b.targetData.TypeAllocSize(x.Type().ElementType()) == 0 {
+		if b.targetData.TypeAllocSize(valueType) == 0 {
 			// zero-length data
 			return llvm.ConstNull(valueType), nil
 		} else if strings.HasSuffix(unop.X.String(), "$funcaddr") {

compiler/func.go

@@ -73,7 +73,7 @@ func (c *compilerContext) getFuncType(typ *types.Signature) llvm.Type {
 	return c.ctx.StructType([]llvm.Type{c.i8ptrType, c.rawVoidFuncType}, false)
 }
 
-// getRawFuncType returns a LLVM function pointer type for a given signature.
+// getRawFuncType returns a LLVM function type for a given signature.
 func (c *compilerContext) getRawFuncType(typ *types.Signature) llvm.Type {
 	// Get the return type.
 	var returnType llvm.Type

compiler/interface.go

@@ -86,7 +86,7 @@ func (c *compilerContext) getTypeCode(typ types.Type) llvm.Value {
 		if _, ok := typ.Underlying().(*types.Pointer); !ok {
 			ptrTo = c.getTypeCode(types.NewPointer(typ))
 		}
-		globalValue := llvm.ConstNull(global.Type().ElementType())
+		globalValue := llvm.ConstNull(global.GlobalValueType())
 		if !references.IsNil() {
 			globalValue = c.builder.CreateInsertValue(globalValue, references, 0, "")
 		}
@@ -533,7 +533,7 @@ func (c *compilerContext) getInterfaceInvokeWrapper(fn *ssa.Function, llvmFnType
 
 	receiverValue := b.emitPointerUnpack(wrapper.Param(0), []llvm.Type{receiverType})[0]
 	params := append(b.expandFormalParam(receiverValue), wrapper.Params()[1:]...)
-	if llvmFn.Type().ElementType().ReturnType().TypeKind() == llvm.VoidTypeKind {
+	if llvmFnType.ReturnType().TypeKind() == llvm.VoidTypeKind {
 		b.CreateCall(llvmFnType, llvmFn, params, "")
 		b.CreateRetVoid()
 	} else {

compiler/ircheck/check.go

@@ -70,10 +70,7 @@ func (c *checker) checkType(t llvm.Type, checked map[llvm.Type]struct{}, special
 			return fmt.Errorf("failed to verify element type of array type %s: %s", t.String(), err.Error())
 		}
 	case llvm.PointerTypeKind:
-		// check underlying type
-		if err := c.checkType(t.ElementType(), checked, specials); err != nil {
-			return fmt.Errorf("failed to verify underlying type of pointer type %s: %s", t.String(), err.Error())
-		}
+		// Pointers can't be checked in an opaque pointer world.
 	case llvm.VectorTypeKind:
 		// check element type
 		if err := c.checkType(t.ElementType(), checked, specials); err != nil {

compiler/symbol.go

@@ -83,7 +83,7 @@ func (c *compilerContext) getFunction(fn *ssa.Function) (llvm.Type, llvm.Value)
 	// Add an extra parameter as the function context. This context is used in
 	// closures and bound methods, but should be optimized away when not used.
 	if !info.exported {
-		paramInfos = append(paramInfos, paramInfo{llvmType: c.i8ptrType, name: "context", flags: 0})
+		paramInfos = append(paramInfos, paramInfo{llvmType: c.i8ptrType, name: "context", elemSize: 0})
 	}
 
 	var paramTypes []llvm.Type
@@ -112,17 +112,8 @@ func (c *compilerContext) getFunction(fn *ssa.Function) (llvm.Type, llvm.Value)
 
 	dereferenceableOrNullKind := llvm.AttributeKindID("dereferenceable_or_null")
 	for i, info := range paramInfos {
-		if info.flags&paramIsDeferenceableOrNull == 0 {
-			continue
-		}
-		if info.llvmType.TypeKind() == llvm.PointerTypeKind {
-			el := info.llvmType.ElementType()
-			size := c.targetData.TypeAllocSize(el)
-			if size == 0 {
-				// dereferenceable_or_null(0) appears to be illegal in LLVM.
-				continue
-			}
-			dereferenceableOrNull := c.ctx.CreateEnumAttribute(dereferenceableOrNullKind, size)
+		if info.elemSize != 0 {
+			dereferenceableOrNull := c.ctx.CreateEnumAttribute(dereferenceableOrNullKind, info.elemSize)
 			llvmFn.AddAttributeAtIndex(i+1, dereferenceableOrNull)
 		}
 	}