Revert "[ VM ] Print a meaningful error message when a user attempts to run an AOT snapshot with a JIT VM."

This reverts commit d870a71.

Reason for revert: ASAN failures

Original change's description:
> [ VM ] Print a meaningful error message when a user attempts to run an AOT snapshot with a JIT VM.
> 
> Fixes #42482
> 
> Change-Id: I284a5673e30f59b127e69c712df93552cdfcde41
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/154834
> Commit-Queue: Ben Konyi <[email protected]>
> Reviewed-by: Ryan Macnak <[email protected]>

[email protected],[email protected],[email protected]

Change-Id: I3639ede6987fbb51fb95584685c472abb789970e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/155303
Reviewed-by: Ben Konyi <[email protected]>
Commit-Queue: Ben Konyi <[email protected]>

Author: bkonyi

runtime/bin/main.cc

@@ -1221,16 +1221,9 @@ void main(int argc, char** argv) {
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)
 
   if (should_run_user_program) {
-    if (!Dart_IsPrecompiledRuntime() && Snapshot::IsAOTSnapshot(script_name)) {
-      Syslog::PrintErr(
-          "%s is an AOT snapshot and should be run with 'dartaotruntime'\n",
-          script_name);
-      Platform::Exit(kErrorExitCode);
-    } else {
-      // Run the main isolate until we aren't told to restart.
-      while (RunMainIsolate(script_name, &dart_options)) {
-        Syslog::PrintErr("Restarting VM\n");
-      }
+    // Run the main isolate until we aren't told to restart.
+    while (RunMainIsolate(script_name, &dart_options)) {
+      Syslog::PrintErr("Restarting VM\n");
     }
   }
 

runtime/bin/snapshot_utils.cc

@@ -537,24 +537,5 @@ void Snapshot::GenerateAppAOTAsAssembly(const char* snapshot_filename) {
   }
 }
 
-bool Snapshot::IsAOTSnapshot(const char* snapshot_filename) {
-  // Header is simply "ELF" prefixed with the DEL character.
-  const char elf_header[] = {0x7F, 0x45, 0x4C, 0x46};
-  const int64_t elf_header_len = strlen(elf_header);
-  File* file = File::Open(NULL, snapshot_filename, File::kRead);
-  if (file == nullptr) {
-    return false;
-  }
-  if (file->Length() < elf_header_len) {
-    file->Release();
-    return false;
-  }
-  auto buf = std::unique_ptr<char[]>(new char[elf_header_len]);
-  bool success = file->ReadFully(buf.get(), elf_header_len);
-  file->Release();
-  ASSERT(success);
-  return (strncmp(elf_header, buf.get(), elf_header_len) == 0);
-}
-
 }  // namespace bin
 }  // namespace dart

runtime/bin/snapshot_utils.h

@@ -34,10 +34,6 @@ class Snapshot {
   static void GenerateAppJIT(const char* snapshot_filename);
   static void GenerateAppAOTAsAssembly(const char* snapshot_filename);
 
-  // Returns true if snapshot_filename points to an AOT snapshot (aka,
-  // an ELF binary). May report false negatives.
-  static bool IsAOTSnapshot(const char* snapshot_filename);
-
   static AppSnapshot* TryReadAppendedAppSnapshotElf(const char* container_path);
   static AppSnapshot* TryReadAppSnapshot(
       const char* script_uri,

tests/standalone/check_for_aot_snapshot_jit_test.dart

@@ -6,7 +6,6 @@
 dwarf_stack_trace_test: Pass, RuntimeError # Issue 35563
 
 [ $runtime == dart_precompiled ]
-check_for_aot_snapshot_jit_test: SkipByDesign
 http_launch_test: Skip
 io/addlatexhash_test: Skip
 io/dart_std_io_pipe_test: Skip

tests/standalone/standalone_precompiled.status

@@ -3,7 +3,6 @@
 # BSD-style license that can be found in the LICENSE file.
 
 [ $runtime == dart_precompiled ]
-check_for_aot_snapshot_jit_test: SkipByDesign
 http_launch_test: Skip
 io/addlatexhash_test: Skip
 io/dart_std_io_pipe_test: Skip