[Backtracing] Rename a couple of functions, some comment changes.

Renamed a couple of functions following review feedback.  Also added some
extra words to the comments.

rdar://103071801

Author: al45tair

include/swift/Runtime/Paths.h

@@ -28,7 +28,7 @@
 ///         owned by the runtime and should not be freed.
 SWIFT_RUNTIME_EXPORT
 const char *
-swift_getRuntimePath();
+swift_getRuntimeLibraryPath();
 
 /// Return the path of the Swift root.
 ///
@@ -40,7 +40,8 @@ swift_getRuntimePath();
 ///
 /// \return A string containing the full path to the Swift root directory, based
 ///         either on the location of the Swift runtime, or on the `SWIFT_ROOT`
-///         environment variable if set.
+///         environment variable if set.  The string is owned by the runtime
+///         and should not be freed.
 SWIFT_RUNTIME_EXPORT
 const char *
 swift_getRootPath();
@@ -73,6 +74,6 @@ swift_getRootPath();
 ///         should be released with `free()` when no longer required.
 SWIFT_RUNTIME_EXPORT
 const char *
-swift_getAuxiliaryExecutablePath(const char *name);
+swift_copyAuxiliaryExecutablePath(const char *name);
 
 #endif // SWIFT_RUNTIME_PATHS_H

stdlib/public/runtime/Paths.cpp

@@ -74,7 +74,7 @@ bool _swift_exists(const char *path);
 
 SWIFT_RUNTIME_EXPORT
 const char *
-swift_getRuntimePath()
+swift_getRuntimeLibraryPath()
 {
   swift::once(runtimePathToken, _swift_initRuntimePath, nullptr);
   return runtimePath;
@@ -121,7 +121,7 @@ _swift_lookingAtBin(const char *ptr, const char *base)
 const char *
 _swift_getDefaultRootPath()
 {
-  const char *runtimePath = swift_getRuntimePath();
+  const char *runtimePath = swift_getRuntimeLibraryPath();
   size_t runtimePathLen = std::strlen(runtimePath);
 
   // Scan backwards until we find a path separator
@@ -357,7 +357,7 @@ _swift_win32NameFromNTName(LPWSTR pszFilename) {
 
 SWIFT_RUNTIME_EXPORT
 const char *
-swift_getAuxiliaryExecutablePath(const char *name)
+swift_copyAuxiliaryExecutablePath(const char *name)
 {
   const char *rootPath = swift_getRootPath();
 

test/Runtime/Paths.cpp

@@ -22,6 +22,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -60,7 +61,7 @@ containsLibSwift(const char *path) {
 }
 
 int main(void) {
-  const char *runtimePath = swift_getRuntimePath();
+  const char *runtimePath = swift_getRuntimeLibraryPath();
 
   // Runtime path must point to libswiftCore and must be a file.
 
@@ -89,12 +90,14 @@ int main(void) {
   printf("root path contains /lib/swift/: %s\n",
          containsLibSwift(rootPath) ? "yes" : "no");
 
-  const char *auxPath = swift_getAuxiliaryExecutablePath("Foo");
+  const char *auxPath = swift_copyAuxiliaryExecutablePath("Foo");
 
   // CHECK: aux path: <NULL>
   // CHECK-FR: aux path: {{.*[\\/]libexec[\\/]swift[\\/]Foo(\.exe)?}}
 
   printf("aux path: %s\n", auxPath ? auxPath : "<NULL>");
 
+  free(auxPath);
+
   return 0;
 }