Toward precompiled snapshots.

runtime/bin/main.cc

Index: runtime/bin/main.cc
diff --git a/runtime/bin/main.cc b/runtime/bin/main.cc
index 4e2b24acce608c4e11f99cce29d897f7384bef8b..b657bff5cd2dc23a9e482df11f2f1fa15d2ff094 100644
--- a/runtime/bin/main.cc
+++ b/runtime/bin/main.cc
@@ -76,6 +76,11 @@ static bool has_compile_all = false;
 static bool has_precompile = false;
 
 
+// Global flag that is used to indicate that we want to run from a precompiled
+// snapshot.
+static bool has_precompiled = false;
+
+
 // Global flag that is used to indicate that we want to trace resolution of
 // URIs and the loading of libraries, parts and scripts.
 static bool has_trace_loading = false;
@@ -301,6 +306,18 @@ static bool ProcessPrecompileOption(const char* arg,
 }
 
 
+static bool ProcessPrecompiledOption(const char* arg,
+                                     CommandLineOptions* vm_options) {
+  ASSERT(arg != NULL);
+  if (*arg != '\0') {
+    return false;
+  }
+  has_precompiled = true;
+  vm_options->AddArgument("--precompile");
+  return true;
+}
+
+
 static bool ProcessDebugOption(const char* option_value,
                                CommandLineOptions* vm_options) {
   ASSERT(option_value != NULL);
@@ -412,6 +429,7 @@ static struct {
   { "--break-at=", ProcessBreakpointOption },
   { "--compile_all", ProcessCompileAllOption },
   { "--precompile", ProcessPrecompileOption },
+  { "--precompiled", ProcessPrecompiledOption },
   { "--debug", ProcessDebugOption },
   { "--snapshot=", ProcessGenScriptSnapshotOption },
   { "--enable-vm-service", ProcessEnableVmServiceOption },
@@ -959,6 +977,18 @@ static void ServiceStreamCancelCallback(const char* stream_id) {
 }
 
 
+static void WriteSnapshotFile(const char* filename,
+                              const uint8_t* buffer,
+                              const intptr_t size) {
+  File* file = File::Open(filename, File::kWriteTruncate);
+  ASSERT(file != NULL);
+  if (!file->WriteFully(buffer, size)) {
+    Log::PrintErr("Error: Failed to write snapshot file.\n\n");
+  }
+  delete file;
+}
+
+
 void main(int argc, char** argv) {
   char* script_name;
   const int EXTRA_VM_ARGUMENTS = 2;
@@ -1032,8 +1062,62 @@ void main(int argc, char** argv) {
     DebuggerConnectionHandler::InitForVmService();
   }
 
+  const uint8_t* instructions_snapshot = NULL;
+  if (has_precompiled) {
+    const char* kPrecompiledLibName = "libprecompiled.so";

[siva, 2015/09/01 20:58:48]

This name seems specific to linux, maybe it should move out to a target specific
file.

[rmacnak, 2015/09/01 23:43:47]

Done.

+    const char* kPrecompiledSymName = "kInstructionsSnapshot";
+    const char* kPrecompiledVmIsolateName = "precompiled.vmisolate";
+    const char* kPrecompiledIsolateName = "precompiled.isolate";
+
+    void* precompiled_lib =
+        Extensions::LoadExtensionLibrary(kPrecompiledLibName);
+    if (precompiled_lib == NULL) {
+      fprintf(stderr, "Failed to load library '%s'\n", kPrecompiledLibName);
+      fflush(stderr);
+      exit(kErrorExitCode);
+    }
+
+    instructions_snapshot = reinterpret_cast<const uint8_t*>(
+        Extensions::ResolveSymbol(precompiled_lib, kPrecompiledSymName));
+    if (instructions_snapshot == NULL) {
+      fprintf(stderr, "Failed to load symbol '%s'\n", kPrecompiledSymName);
+      fflush(stderr);
+      exit(kErrorExitCode);
+    }
+
+    void* file = DartUtils::OpenFile(kPrecompiledVmIsolateName, false);
+    if (file == NULL) {
+      fprintf(stderr, "Failed to open '%s'\n", kPrecompiledVmIsolateName);
+      fflush(stderr);
+      exit(kErrorExitCode);
+    }
+    intptr_t len = -1;
+    DartUtils::ReadFile(&vm_isolate_snapshot_buffer, &len, file);
+    if (vm_isolate_snapshot_buffer == NULL || len == -1) {
+      fprintf(stderr, "Failed to read '%s'\n", kPrecompiledVmIsolateName);
+      fflush(stderr);
+      exit(kErrorExitCode);
+    }
+    DartUtils::CloseFile(file);
+
+    file = DartUtils::OpenFile(kPrecompiledIsolateName, false);
+    if (file == NULL) {
+      fprintf(stderr, "Failed to open '%s'\n", kPrecompiledIsolateName);
+      fflush(stderr);
+      exit(kErrorExitCode);
+    }
+    len = -1;
+    DartUtils::ReadFile(&isolate_snapshot_buffer, &len, file);
+    if (isolate_snapshot_buffer == NULL || len == -1) {
+      fprintf(stderr, "Failed to read '%s'\n", kPrecompiledVmIsolateName);
+      fflush(stderr);
+      exit(kErrorExitCode);
+    }
+    DartUtils::CloseFile(file);

[siva, 2015/09/01 20:58:49]

The above code of reading a snapshot file is repeated multiple times, maybe you
could have a helper
ReadSnapshotFile(const char* name, char* buffer, intptr_t* len);

[rmacnak, 2015/09/01 23:43:47]

Done.

+  }
+
   // Initialize the Dart VM.
-  if (!Dart_Initialize(vm_isolate_snapshot_buffer, NULL,
+  if (!Dart_Initialize(vm_isolate_snapshot_buffer, instructions_snapshot,
                        CreateIsolateAndSetup, NULL, NULL, ShutdownIsolate,
                        DartUtils::OpenFile,
                        DartUtils::ReadFile,
@@ -1114,6 +1198,32 @@ void main(int argc, char** argv) {
     if (has_precompile) {
       result = Dart_Precompile();
       DartExitOnError(result);
+
+      uint8_t* vm_isolate_buffer = NULL;
+      intptr_t vm_isolate_size = 0;
+      uint8_t* isolate_buffer = NULL;
+      intptr_t isolate_size = 0;
+      uint8_t* instructions_buffer = NULL;
+      intptr_t instructions_size = 0;
+      result = Dart_CreatePrecompiledSnapshot(&vm_isolate_buffer,
+                                              &vm_isolate_size,
+                                              &isolate_buffer,
+                                              &isolate_size,
+                                              &instructions_buffer,
+                                              &instructions_size);
+
+      DartExitOnError(result);
+
+      WriteSnapshotFile("precompiled.vmisolate",
+                        vm_isolate_buffer,
+                        vm_isolate_size);
+      WriteSnapshotFile("precompiled.isolate",
+                        isolate_buffer,
+                        isolate_size);
+      WriteSnapshotFile("precompiled.instructions",
+                        instructions_buffer,
+                        instructions_size);

[siva, 2015/09/01 20:58:48]

You should extract these names as constants and use them in both the
has_precompile and has_precompiled case.
e.g:

i.e extract the stuff you have above
const char* kPrecompiledSymName = "kInstructionsSnapshot";
const char* kPrecompiledVmIsolateName = "precompiled.vmisolate";
const char* kPrecompiledIsolateName = "precompiled.isolate"

and make them available globally in this file.
static const char* kPrecompiledVmIsolateSnapshot = "...";
static const char* kPrecompiledIsolateSnapshot = "....";
static const char* kPrecompiledInstructions = "...";

[rmacnak, 2015/09/01 23:43:47]

Done.

+
     } else if (has_compile_all) {
       result = Dart_CompileAll();
       DartExitOnError(result);