Process tilde in llvm::sys::path::native.

[sepavloff]

Summary

Windows does not treat ~ as a reference to home directory, so the call
to llvm::sys::path::native on, say, ~/somedir produces ~\somedir,
which has different meaning than the original path. With this change
tilde is expanded on Windows to user profile directory. Such behavior
keeps original meaning of the path and is consistent with the algorithm
of llvm::sys::path::home_directory.

[rnk]

Seems like reasonable functionality. I just have a few comments on the unittest. If SmallString doesn't do operator==, they're mostly irrelevant.

unittests/Support/Path.cpp

979–981

Does this simplify to EXPECT_EQ(Path7, PathHome + "\\aaa")? If so we don't need the const char * local.

986

Does EXPECT_EQ work?

[sepavloff]

Use EXPECT_EQ instead of EXPECT_TRUE in unit test.

[sepavloff]

unittests/Support/Path.cpp

979–981

SmallString does not have operator +. It has operator += but it does not help here.

986

Yes, it works, as SmallString has operator == inherited from SmallVectorImpl.
It also works in comparisons with string literals, due to presence of:

• operator==(StringRef, StringRef)
• SmallString::operator StringRef()
• StringRef(const char *)

Corresponding checks were updated accordingly.

[rnk]

lgtm

lib/Support/Path.cpp

assert((!path.isSingleStringRef() ||
          "path and result are not allowed to overlap!");
   // Clear result.
   result.clear();
   path.toVector(result);
   native(result);
 }
 
 void native(SmallVectorImpl<char> &Path) {
+  if (Path.empty())
+    return;
 #ifdef LLVM_ON_WIN32
   std::replace(Path.begin(), Path.end(), '/', '\\');
+  if (Path[0] == '~' && (Path.size() == 1 || is_separator(Path[1]))) {
+    SmallString<128> PathHome;
+    home_directory(PathHome);
+    PathHome.append(Path.begin() + 1, Path.end());
+    Path = PathHome;
+  }
 #else
   for (auto PI = Path.begin(), PE = Path.end(); PI < PE; ++PI) {
     if (*PI == '\\') {
       auto PN = PI + 1;
       if (PN < PE && *PN == '\\')
         ++PI; // increment once, the for loop will move over the escaped slash
       else
         *PI = '/';

unittests/Support/Path.cpp

#endif
 
   path::native(Path5);
   EXPECT_PATH_IS(Path5, "\\a", "/a");
 
   path::native(Path6);
   EXPECT_PATH_IS(Path6, "a\\", "a/");
 
 #undef EXPECT_PATH_IS
+
+#if defined(LLVM_ON_WIN32)
+  SmallString<64> PathHome;
+  path::home_directory(PathHome);
+
+  const char *Path7a = "~/aaa";
+  SmallString<64> Path7(Path7a);
+  path::native(Path7);
+  EXPECT_TRUE(Path7.endswith("\\aaa"));
+  EXPECT_TRUE(Path7.startswith(PathHome));
+  EXPECT_EQ(Path7.size(), PathHome.size() + strlen(Path7a + 1));
+
+  const char *Path8a = "~";
+  SmallString<64> Path8(Path8a);
+  path::native(Path8);
+  EXPECT_EQ(Path8, PathHome);
+
+  const char *Path9a = "~aaa";
+  SmallString<64> Path9(Path9a);
+  path::native(Path9);
+  EXPECT_EQ(Path9, "~aaa");
+
+  const char *Path10a = "aaa/~/b";
+  SmallString<64> Path10(Path10a);
+  path::native(Path10);
+  EXPECT_EQ(Path10, "aaa\\~\\b");
+#endif
 }
 
 TEST(Support, RemoveLeadingDotSlash) {
   StringRef Path1("././/foolz/wat");
   StringRef Path2("./////");
 
   Path1 = path::remove_leading_dotslash(Path1);
   EXPECT_EQ(Path1, "foolz/wat");