Add support for opaque pointers and structs

backports.cpp

@@ -48,3 +48,16 @@ LLVMMemoryBufferRef LLVMGoWriteThinLTOBitcodeToMemoryBuffer(LLVMModuleRef M) {
 #endif
   return llvm::wrap(llvm::MemoryBuffer::getMemBufferCopy(OS.str()).release());
 }
+
+#if LLVM_VERSION_MAJOR < 15
+
+// This is backported because version 14 supports opaque
+// pointers but I presume if you try to access the element
+// type it will crash. So this backport prevents that by
+// allowing to check if the pointer is opaque before trying
+// to access the element type.
+LLVMBool LLVMPointerTypeIsOpaque(LLVMTypeRef Ty) {
+  return llvm::unwrap<llvm::Type>(Ty)->isOpaquePointerTy();
+}
+
+#endif

backports.h

@@ -14,6 +14,19 @@ LLVMMemoryBufferRef LLVMGoWriteThinLTOBitcodeToMemoryBuffer(LLVMModuleRef M);
 LLVMMetadataRef LLVMGoDIBuilderCreateExpression(LLVMDIBuilderRef Builder,
                                                 uint64_t *Addr, size_t Length);
 
+#if LLVM_VERSION_MAJOR < 15
+/**
+ * Determine whether a pointer is opaque.
+ *
+ * True if this is an instance of an opaque PointerType.
+ *
+ * @see llvm::Type::isOpaquePointerTy()
+ */
+LLVMBool LLVMPointerTypeIsOpaque(LLVMTypeRef Ty);
+
+#endif
+
+
 #ifdef __cplusplus
 }
 #endif /* defined(__cplusplus) */

ir.go

@@ -16,11 +16,14 @@ package llvm
 #include "llvm-c/Core.h"
 #include "llvm-c/Comdat.h"
 #include "IRBindings.h"
+#include "backports.h"
 #include <stdlib.h>
 */
 import "C"
-import "unsafe"
-import "errors"
+import (
+	"errors"
+	"unsafe"
+)
 
 type (
 	// We use these weird structs here because *Ref types are pointers and
@@ -665,6 +668,7 @@ func (t Type) StructSetBody(elementTypes []Type, packed bool) {
 }
 
 func (t Type) IsStructPacked() bool         { return C.LLVMIsPackedStruct(t.C) != 0 }
+func (t Type) IsStructOpaque() bool         { return C.LLVMIsOpaqueStruct(t.C) != 0 }
 func (t Type) StructElementTypesCount() int { return int(C.LLVMCountStructElementTypes(t.C)) }
 func (t Type) StructElementTypes() []Type {
 	out := make([]Type, t.StructElementTypesCount())
@@ -676,7 +680,12 @@ func (t Type) StructElementTypes() []Type {
 
 // Operations on array, pointer, and vector types (sequence types)
 func (t Type) Subtypes() (ret []Type) {
-	ret = make([]Type, C.LLVMGetNumContainedTypes(t.C))
+	num := C.LLVMGetNumContainedTypes(t.C)
+	if num == 0 {
+		// prevent a crash at &ret[0] if there are no subtypes
+		return nil
+	}
+	ret = make([]Type, num)
 	C.LLVMGetSubtypes(t.C, llvmTypeRefPtr(&ret[0]))
 	return
 }
@@ -694,7 +703,19 @@ func VectorType(elementType Type, elementCount int) (t Type) {
 	return
 }
 
-func (t Type) ElementType() (rt Type)   { rt.C = C.LLVMGetElementType(t.C); return }
+// IsPointerOpaque checks if the pointer is an opaque pointer.
+//
+// see llvm::Type::isOpaquePointerTy()
+func (t Type) IsPointerOpaque() bool { return C.LLVMPointerTypeIsOpaque(t.C) != 0 }
+
+// ElementType returns the type of the element for arrays, pointers and vectors.
+//
+// see llvm::SequentialType::getElementType()
+func (t Type) ElementType() (rt Type) {
+	rt.C = C.LLVMGetElementType(t.C)
+	return
+}
+
 func (t Type) ArrayLength() int         { return int(C.LLVMGetArrayLength(t.C)) }
 func (t Type) PointerAddressSpace() int { return int(C.LLVMGetPointerAddressSpace(t.C)) }
 func (t Type) VectorSize() int          { return int(C.LLVMGetVectorSize(t.C)) }