Expose GetTargetFromTriple from LLVMTargetRef (#153)

Author: jackoalan

sources/LLVMSharp/Interop.Extensions/LLVMTargetMachineRef.cs

@@ -22,18 +22,7 @@ public LLVMTargetMachineRef(IntPtr handle)
 
         public static bool operator !=(LLVMTargetMachineRef left, LLVMTargetMachineRef right) => !(left == right);
 
-        public string CreateTargetDataLayout()
-        {
-            var pDataLayout = LLVM.CreateTargetDataLayout(this);
-
-            if (pDataLayout is null)
-            {
-                return string.Empty;
-            }
-
-            var span = new ReadOnlySpan<byte>(pDataLayout, int.MaxValue);
-            return span.Slice(0, span.IndexOf((byte)'\0')).AsString();
-        }
+        public LLVMTargetDataRef CreateTargetDataLayout() => LLVM.CreateTargetDataLayout(this);
 
         public void EmitToFile(LLVMModuleRef module, string fileName, LLVMCodeGenFileType codegen) => EmitToFile(module, fileName.AsSpan(), codegen);
 

sources/LLVMSharp/Interop.Extensions/LLVMTargetRef.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Runtime.InteropServices;
 
 namespace LLVMSharp.Interop
 {
@@ -30,6 +31,41 @@ public static string DefaultTriple
             }
         }
 
+        public static bool TryGetTargetFromTriple(ReadOnlySpan<char> triple, out LLVMTargetRef outTarget, out string outError)
+        {
+            using var marshaledTriple = new MarshaledString(triple);
+
+            fixed (LLVMTargetRef* pOutTarget = &outTarget)
+            {
+                sbyte* pError;
+                var result = LLVM.GetTargetFromTriple(marshaledTriple, (LLVMTarget**)pOutTarget, &pError);
+
+                if (pError is null)
+                {
+                    outError = string.Empty;
+                }
+                else
+                {
+                    var span = new ReadOnlySpan<byte>(pError, int.MaxValue);
+                    outError = span.Slice(0, span.IndexOf((byte)'\0')).AsString();
+                }
+
+                return result == 0;
+            }
+        }
+
+        public static LLVMTargetRef GetTargetFromTriple(string triple) => GetTargetFromTriple(triple.AsSpan());
+
+        public static LLVMTargetRef GetTargetFromTriple(ReadOnlySpan<char> triple)
+        {
+            if (!TryGetTargetFromTriple(triple, out LLVMTargetRef target, out string message))
+            {
+                throw new ExternalException(message);
+            }
+
+            return target;
+        }
+
         public static LLVMTargetRef First => LLVM.GetFirstTarget();
 
         public static IEnumerable<LLVMTargetRef> Targets

tests/LLVMSharp.UnitTests/TargetData.cs

@@ -67,5 +67,29 @@ public void AlignmentTest()
             LLVMValueRef global = m.AddGlobal(LLVMTypeRef.CreatePointer(LLVMTypeRef.Int8, 0), "someGlobal");
             Assert.AreEqual(4, target.PreferredAlignmentOfGlobal(global));
         }
+
+        private LLVMTargetDataRef TargetDataFromTriple(string triple)
+        {
+            LLVMTargetRef target = LLVMTargetRef.GetTargetFromTriple(triple);
+            LLVMTargetMachineRef targetMachine = target.CreateTargetMachine(triple, "", "",
+                LLVMCodeGenOptLevel.LLVMCodeGenLevelDefault, LLVMRelocMode.LLVMRelocDefault,
+                LLVMCodeModel.LLVMCodeModelDefault);
+            return targetMachine.CreateTargetDataLayout();
+        }
+
+        [Test]
+        public void MachineTest()
+        {
+            LLVM.InitializeX86TargetInfo();
+            LLVM.InitializeX86Target();
+            LLVM.InitializeX86TargetMC();
+
+            LLVMTypeRef pointerType = LLVMTypeRef.CreatePointer(LLVMTypeRef.Int32, 0);
+            LLVMTargetDataRef x86 = TargetDataFromTriple("i386-unknown-unknown");
+            LLVMTargetDataRef x86_64 = TargetDataFromTriple("amd64-unknown-unknown");
+
+            Assert.AreEqual(4, x86.ABISizeOfType(pointerType));
+            Assert.AreEqual(8, x86_64.ABISizeOfType(pointerType));
+        }
     }
 }