[Module] sourceFileName

Per #223

Author: matthewseaman

Sources/LLVM/Module.swift

@@ -142,7 +142,27 @@ public final class Module: CustomStringConvertible {
       LLVMSetModuleIdentifier(llvm, newValue, newValue.utf8.count)
     }
   }
-
+  
+  /// The source filename of this module.
+  ///
+  /// The source filename appears at the top of an IR module:
+  ///
+  ///     source_filename = "/path/to/source.c"
+  ///
+  /// Local functions used in profile data prepend the source file name to the local function name.
+  ///
+  /// If not otherwise set, `name` is used.
+  public var sourceFileName: String {
+    get {
+      var count = 0
+      guard let fn = LLVMGetSourceFileName(llvm, &count) else { return "" }
+      return String(cString: fn)
+    }
+    set {
+      LLVMSetSourceFileName(llvm, newValue, newValue.utf8.count)
+    }
+  }
+  
   /// Retrieves the inline assembly for this module, if any.
   public var inlineAssembly: String {
     get {

Tests/LLVMTests/ModuleLinkSpec.swift

@@ -22,10 +22,14 @@ class ModuleLinkSpec : XCTestCase {
       // MODULE-LINK-NEXT: }
       module1.dump()
 
-      // MODULE-LINK: ; ModuleID = '[[ModuleName2:ModuleLinkModuleTwo]]'
-      // MODULE-LINK-NEXT: source_filename = "[[ModuleName2]]"
+      // MODULE-LINK: ; ModuleID = 'ModuleLinkModuleTwo'
+      // MODULE-LINK-NEXT: source_filename = "/Users/user/Developer/Project/file.ext"
       let module2 = Module(name: "ModuleLinkModuleTwo")
       XCTAssertEqual(module2.name, "ModuleLinkModuleTwo")
+      XCTAssertEqual(module2.sourceFileName, "ModuleLinkModuleTwo")
+      module2.sourceFileName = "/Users/user/Developer/Project/file.ext"
+      XCTAssertEqual(module2.sourceFileName, "/Users/user/Developer/Project/file.ext")
+      
       let builder2 = IRBuilder(module: module2)
       // MODULE-LINK: define void @moduleTwo() {
       let mod2f = builder2.addFunction("moduleTwo",