[lldb] Improve error message for unrecognized executables

lldb/include/lldb/Symbol/ObjectFile.h

@@ -178,6 +178,7 @@ class ObjectFile : public std::enable_shared_from_this<ObjectFile>,
                                         lldb::offset_t file_offset,
                                         lldb::offset_t file_size,
                                         lldb_private::ModuleSpecList &specs);
+  static bool IsObjectFile(lldb_private::FileSpec file_spec);
   /// Split a path into a file path with object name.
   ///
   /// For paths like "/tmp/foo.a(bar.o)" we often need to split a path up into

lldb/source/Symbol/ObjectFile.cpp

@@ -184,6 +184,15 @@ ObjectFileSP ObjectFile::FindPlugin(const lldb::ModuleSP &module_sp,
   return object_file_sp;
 }
 
+bool ObjectFile::IsObjectFile(lldb_private::FileSpec file_spec) {
+  DataBufferSP data_sp;
+  offset_t data_offset = 0;
+  ModuleSP module_sp = std::make_shared<Module>(file_spec);
+  return static_cast<bool>(ObjectFile::FindPlugin(
+      module_sp, &file_spec, 0, FileSystem::Instance().GetByteSize(file_spec),
+      data_sp, data_offset));
+}
+
 size_t ObjectFile::GetModuleSpecifications(const FileSpec &file,
                                            lldb::offset_t file_offset,
                                            lldb::offset_t file_size,

lldb/source/Target/Platform.cpp

@@ -766,7 +766,6 @@ Status
 Platform::ResolveExecutable(const ModuleSpec &module_spec,
                             lldb::ModuleSP &exe_module_sp,
                             const FileSpecList *module_search_paths_ptr) {
-  Status error;
 
   // We may connect to a process and use the provided executable (Don't use
   // local $PATH).
@@ -775,55 +774,57 @@ Platform::ResolveExecutable(const ModuleSpec &module_spec,
   // Resolve any executable within a bundle on MacOSX
   Host::ResolveExecutableInBundle(resolved_module_spec.GetFileSpec());
 
-  if (FileSystem::Instance().Exists(resolved_module_spec.GetFileSpec()) ||
-      module_spec.GetUUID().IsValid()) {
-    if (resolved_module_spec.GetArchitecture().IsValid() ||
-        resolved_module_spec.GetUUID().IsValid()) {
-      error = ModuleList::GetSharedModule(resolved_module_spec, exe_module_sp,
-                                          module_search_paths_ptr, nullptr,
-                                          nullptr);
+  if (!FileSystem::Instance().Exists(resolved_module_spec.GetFileSpec()) &&
+      !module_spec.GetUUID().IsValid())
+    return Status::createWithFormat("'{0}' does not exist",
+                                    resolved_module_spec.GetFileSpec());
+
+  if (resolved_module_spec.GetArchitecture().IsValid() ||
+      resolved_module_spec.GetUUID().IsValid()) {
+    Status error =
+        ModuleList::GetSharedModule(resolved_module_spec, exe_module_sp,
+                                    module_search_paths_ptr, nullptr, nullptr);
 
+    if (exe_module_sp && exe_module_sp->GetObjectFile())
+      return error;
+    exe_module_sp.reset();
+  }
+  // No valid architecture was specified or the exact arch wasn't found.
+  // Ask the platform for the architectures that we should be using (in the
+  // correct order) and see if we can find a match that way.
+  StreamString arch_names;
+  llvm::ListSeparator LS;
+  ArchSpec process_host_arch;
+  Status error;
+  for (const ArchSpec &arch : GetSupportedArchitectures(process_host_arch)) {
+    resolved_module_spec.GetArchitecture() = arch;
+    error =
+        ModuleList::GetSharedModule(resolved_module_spec, exe_module_sp,
+                                    module_search_paths_ptr, nullptr, nullptr);
+    if (error.Success()) {
       if (exe_module_sp && exe_module_sp->GetObjectFile())
-        return error;
-      exe_module_sp.reset();
+        break;
+      error.SetErrorToGenericError();
     }
-    // No valid architecture was specified or the exact arch wasn't found.
-    // Ask the platform for the architectures that we should be using (in the
-    // correct order) and see if we can find a match that way.
-    StreamString arch_names;
-    llvm::ListSeparator LS;
-    ArchSpec process_host_arch;
-    for (const ArchSpec &arch : GetSupportedArchitectures(process_host_arch)) {
-      resolved_module_spec.GetArchitecture() = arch;
-      error = ModuleList::GetSharedModule(resolved_module_spec, exe_module_sp,
-                                          module_search_paths_ptr, nullptr,
-                                          nullptr);
-      if (error.Success()) {
-        if (exe_module_sp && exe_module_sp->GetObjectFile())
-          break;
-        error.SetErrorToGenericError();
-      }
 
-      arch_names << LS << arch.GetArchitectureName();
-    }
+    arch_names << LS << arch.GetArchitectureName();
+  }
 
-    if (error.Fail() || !exe_module_sp) {
-      if (FileSystem::Instance().Readable(resolved_module_spec.GetFileSpec())) {
-        error.SetErrorStringWithFormatv(
-            "'{0}' doesn't contain any '{1}' platform architectures: {2}",
-            resolved_module_spec.GetFileSpec(), GetPluginName(),
-            arch_names.GetData());
-      } else {
-        error.SetErrorStringWithFormatv("'{0}' is not readable",
-                                        resolved_module_spec.GetFileSpec());
-      }
-    }
-  } else {
-    error.SetErrorStringWithFormatv("'{0}' does not exist",
+  if (exe_module_sp && error.Success())
+    return {};
+
+  if (!FileSystem::Instance().Readable(resolved_module_spec.GetFileSpec()))
+    return Status::createWithFormat("'{0}' is not readable",
                                     resolved_module_spec.GetFileSpec());
-  }
 
-  return error;
+  if (!ObjectFile::IsObjectFile(resolved_module_spec.GetFileSpec()))
+    return Status::createWithFormat("'{0}' is not a valid executable",
+                                    resolved_module_spec.GetFileSpec());
+
+  return Status::createWithFormat(
+      "'{0}' doesn't contain any '{1}' platform architectures: {2}",
+      resolved_module_spec.GetFileSpec(), GetPluginName(),
+      arch_names.GetData());
 }
 
 Status Platform::ResolveSymbolFile(Target &target, const ModuleSpec &sym_spec,

lldb/test/Shell/ObjectFile/PECOFF/invalid-export-table.yaml

@@ -4,7 +4,7 @@
 # RUN: yaml2obj %s -o %t.exe
 # RUN: %lldb %t.exe 2>&1 | FileCheck %s
 
-# CHECK: error: '{{.*}}' doesn't contain any {{.*}} platform architectures
+# CHECK: error: '{{.*}}' is not a valid executable
 --- !COFF
 OptionalHeader:
   AddressOfEntryPoint: 4096