Prefix scripts from core builtin libraries so the URIs are unique.

After https://dart-review.googlesource.com/c/sdk/+/7588 we ended up with two crypto.dart files in the core prebuilt libraries(io and _http), which caused problem with coverage tool that relied on the fact that script uris can uniquely identify files. dart-lang/coverage#194 was filed to handle non-unique uris.
This CL ensures that core builtin libraries URIs stays unique by prefixing them with 'dart:' library prefix. This makes core builtin libraries scripts have names similarly structured to script names for other core libraries.

Bug:
Change-Id: I79960f4f24e6e958836df866365355584c28df27
Reviewed-on: https://dart-review.googlesource.com/11140
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>

runtime/bin/builtin.cc

@@ -10,6 +10,10 @@
 #include "bin/dartutils.h"
 #include "bin/platform.h"
 
+#include "vm/dart_api_impl.h"
+#include "vm/object.h"
+#include "vm/object_store.h"
+
 namespace dart {
 namespace bin {
 
@@ -53,9 +57,11 @@ static void LoadPatchFiles(Dart_Handle library,
         reinterpret_cast<const uint8_t*>(source), strlen(source));
 
     // Prepend the patch library URI to form a unique script URI for the patch.
-    intptr_t len = snprintf(NULL, 0, "%s/%s", patch_uri, patch_files[j]);
+    const char* unprefixed_patch_file = strchr(patch_files[j], '/') + 1;
+    intptr_t len = snprintf(NULL, 0, "%s/%s", patch_uri, unprefixed_patch_file);
     char* patch_filename = DartUtils::ScopedCString(len + 1);
-    snprintf(patch_filename, len + 1, "%s/%s", patch_uri, patch_files[j]);
+    snprintf(patch_filename, len + 1, "%s/%s", patch_uri,
+             unprefixed_patch_file);
     Dart_Handle patch_file_uri = DartUtils::NewString(patch_filename);
 
     DART_CHECK_VALID(Dart_LibraryLoadPatch(library, patch_file_uri, patch_src));

runtime/bin/gen_snapshot.cc

@@ -653,9 +653,16 @@ static Dart_Handle CreateSnapshotLibraryTagHandler(Dart_LibraryTag tag,
   if (libraryBuiltinId != Builtin::kInvalidLibrary) {
     // Special case for parting sources of a builtin library.
     if (tag == Dart_kSourceTag) {
-      return Dart_LoadSource(library, url, Dart_Null(),
-                             Builtin::PartSource(libraryBuiltinId, url_string),
-                             0, 0);
+      intptr_t len = snprintf(NULL, 0, "%s/%s", library_url_string, url_string);
+      char* patch_filename = reinterpret_cast<char*>(malloc(len + 1));
+      snprintf(patch_filename, len + 1, "%s/%s", library_url_string,
+               url_string);
+      Dart_Handle prefixed_url = Dart_NewStringFromCString(patch_filename);
+      Dart_Handle result = Dart_LoadSource(
+          library, prefixed_url, Dart_Null(),
+          Builtin::PartSource(libraryBuiltinId, patch_filename), 0, 0);
+      free(patch_filename);
+      return result;
     }
     ASSERT(tag == Dart_kImportTag);
     return DartUtils::NewError("Unable to import '%s' ", url_string);

runtime/bin/loader.cc

@@ -845,9 +845,11 @@ Dart_Handle Loader::DartColonLibraryTagHandler(Dart_LibraryTag tag,
     char* part_uri = reinterpret_cast<char*>(malloc(len + 1));
     snprintf(part_uri, len + 1, "%s/%s", library_url_string, url_string);
     Dart_Handle part_uri_obj = DartUtils::NewString(part_uri);
+    Dart_Handle result =
+        Dart_LoadSource(library, part_uri_obj, Dart_Null(),
+                        Builtin::PartSource(id, part_uri), 0, 0);
     free(part_uri);
-    return Dart_LoadSource(library, part_uri_obj, Dart_Null(),
-                           Builtin::PartSource(id, url_string), 0, 0);
+    return result;
   }
   // All cases should have been handled above.
   UNREACHABLE();

runtime/tools/gen_library_src_paths.py

@@ -64,7 +64,7 @@ def makeFile(output_file, input_cc_file, include, var_name, lib_name, in_files):
         if (main_file_found):
           continue
       part_index.append(' "' +
-          os.path.basename(string_file).replace('\\', '\\\\') + '",\n')
+          lib_name + "/" + os.path.basename(string_file).replace('\\', '\\\\') + '",\n')
       part_index.append(' source_array_' + str(file_count) + ',\n\n')
   bootstrap_cc_text = bootstrap_cc_text.replace("{{LIBRARY_SOURCE_MAP}}", '')
   bootstrap_cc_text = bootstrap_cc_text.replace("{{PART_SOURCE_MAP}}",

runtime/vm/bootstrap.cc

@@ -79,7 +79,8 @@ static RawString* GetLibrarySourceByIndex(intptr_t index,
   return String::FromUTF8(utf8_array, file_length);
 }
 
-static RawString* GetLibrarySource(const Library& lib,
+static RawString* GetLibrarySource(Zone* zone,
+                                   const Library& lib,
                                    const String& uri,
                                    bool patch) {
   // First check if this is a valid bootstrap library and find its index in
@@ -95,7 +96,13 @@ static RawString* GetLibrarySource(const Library& lib,
     return String::null();  // The library is not a bootstrap library.
   }
 
-  return GetLibrarySourceByIndex(index, uri, patch);
+  const Array& strings = Array::Handle(zone, Array::New(3));
+  strings.SetAt(0, lib_uri);
+  strings.SetAt(1, Symbols::Slash());
+  strings.SetAt(2, uri);
+  const String& part_uri = String::Handle(zone, String::ConcatAll(strings));
+
+  return GetLibrarySourceByIndex(index, part_uri, patch);
 }
 
 static RawError* Compile(const Library& library, const Script& script) {
@@ -122,7 +129,7 @@ static Dart_Handle LoadPartSource(Thread* thread,
                                   const String& uri) {
   Zone* zone = thread->zone();
   const String& part_source =
-      String::Handle(zone, GetLibrarySource(lib, uri, false));
+      String::Handle(zone, GetLibrarySource(zone, lib, uri, false));
   const String& lib_uri = String::Handle(zone, lib.url());
   if (part_source.IsNull()) {
     return Api::NewError("Unable to read part file '%s' of library '%s'",