appendSuffix: don't append a dot when the suffix is empty.

Additionally, move the implementation of appendSuffix to Path.cpp: it is
platform-independent.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118089 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/System/Path.h

@@ -454,7 +454,8 @@ namespace sys {
       /// The precondition for this function is that the Path reference a file
       /// name (i.e. isFile() returns true). If the Path is not a file, no
       /// action is taken and the function returns false. If the path would
-      /// become invalid for the host operating system, false is returned.
+      /// become invalid for the host operating system, false is returned. When
+      /// the \p suffix is empty, no action is performed.
       /// @returns false if the suffix could not be added, true if it was.
       /// @brief Adds a period and the \p suffix to the end of the pathname.
       bool appendSuffix(StringRef suffix);

lib/System/Path.cpp

@@ -195,6 +195,21 @@ StringRef Path::GetDLLSuffix() {
   return &(LTDL_SHLIB_EXT[1]);
 }
 
+bool
+Path::appendSuffix(StringRef suffix) {
+  if (!suffix.empty()) {
+    std::string save(path);
+    path.append(".");
+    path.append(suffix);
+    if (!isValid()) {
+      path = save;
+      return false;
+    }
+  }
+
+  return true;
+}
+
 bool
 Path::isBitcodeFile() const {
   std::string actualMagic;

lib/System/Unix/Path.inc

@@ -637,18 +637,6 @@ Path::eraseComponent() {
   return true;
 }
 
-bool
-Path::appendSuffix(StringRef suffix) {
-  std::string save(path);
-  path.append(".");
-  path.append(suffix);
-  if (!isValid()) {
-    path = save;
-    return false;
-  }
-  return true;
-}
-
 bool
 Path::eraseSuffix() {
   std::string save = path;

lib/System/Win32/Path.inc

@@ -551,18 +551,6 @@ Path::eraseComponent() {
   return true;
 }
 
-bool
-Path::appendSuffix(StringRef suffix) {
-  std::string save(path);
-  path.append(".");
-  path.append(suffix);
-  if (!isValid()) {
-    path = save;
-    return false;
-  }
-  return true;
-}
-
 bool
 Path::eraseSuffix() {
   size_t dotpos = path.rfind('.',path.size());