Cherry-pick "Re-land "Add an -fno-temp-file flag for compilation""

clang/include/clang/Driver/Options.td

@@ -1530,6 +1530,9 @@ def fno_strict_enums : Flag<["-"], "fno-strict-enums">, Group<f_Group>;
 def fno_strict_vtable_pointers: Flag<["-"], "fno-strict-vtable-pointers">,
   Group<f_Group>;
 def fno_strict_overflow : Flag<["-"], "fno-strict-overflow">, Group<f_Group>;
+def fno_temp_file : Flag<["-"], "fno-temp-file">, Group<f_Group>,
+  Flags<[CC1Option, CoreOption]>, HelpText<
+  "Directly create compilation output files. This may lead to incorrect incremental builds if the compiler crashes">;
 def fno_threadsafe_statics : Flag<["-"], "fno-threadsafe-statics">, Group<f_Group>,
   Flags<[CC1Option]>, HelpText<"Do not emit code to make initialization of local statics thread safe">;
 def fno_use_cxa_atexit : Flag<["-"], "fno-use-cxa-atexit">, Group<f_Group>, Flags<[CC1Option]>,

clang/include/clang/Frontend/FrontendOptions.h

@@ -291,6 +291,9 @@ class FrontendOptions {
   /// Whether timestamps should be written to the produced PCH file.
   unsigned IncludeTimestamps : 1;
 
+  /// Should a temporary file be used during compilation.
+  unsigned UseTemporary : 1;
+
   CodeCompleteOptions CodeCompleteOpts;
 
   /// Specifies the output format of the AST.
@@ -440,8 +443,8 @@ class FrontendOptions {
         UseGlobalModuleIndex(true), GenerateGlobalModuleIndex(true),
         ASTDumpDecls(false), ASTDumpLookups(false),
         BuildingImplicitModule(false), ModulesEmbedAllFiles(false),
-        IncludeTimestamps(true), IndexIgnoreSystemSymbols(false),
-        IndexRecordCodegenName(false) {}
+        IncludeTimestamps(true), UseTemporary(true),
+        IndexIgnoreSystemSymbols(false), IndexRecordCodegenName(false) {}
 
   /// getInputKindForExtension - Return the appropriate input kind for a file
   /// extension. For example, "c" would return Language::C.

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4785,6 +4785,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   Args.AddLastArg(CmdArgs, options::OPT_ftime_trace);
   Args.AddLastArg(CmdArgs, options::OPT_ftrapv);
   Args.AddLastArg(CmdArgs, options::OPT_malign_double);
+  Args.AddLastArg(CmdArgs, options::OPT_fno_temp_file);
 
   if (Arg *A = Args.getLastArg(options::OPT_ftrapv_handler_EQ)) {
     CmdArgs.push_back("-ftrapv-handler");

clang/lib/Frontend/CompilerInstance.cpp

@@ -687,7 +687,7 @@ CompilerInstance::createDefaultOutputFile(bool Binary, StringRef InFile,
                                           StringRef Extension) {
   return createOutputFile(getFrontendOpts().OutputFile, Binary,
                           /*RemoveFileOnSignal=*/true, InFile, Extension,
-                          /*UseTemporary=*/true);
+                          getFrontendOpts().UseTemporary);
 }
 
 std::unique_ptr<raw_pwrite_stream> CompilerInstance::createNullOutputFile() {

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1868,6 +1868,7 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
   Opts.ModulesEmbedFiles = Args.getAllArgValues(OPT_fmodules_embed_file_EQ);
   Opts.ModulesEmbedAllFiles = Args.hasArg(OPT_fmodules_embed_all_files);
   Opts.IncludeTimestamps = !Args.hasArg(OPT_fno_pch_timestamp);
+  Opts.UseTemporary = !Args.hasArg(OPT_fno_temp_file);
 
   Opts.CodeCompleteOpts.IncludeMacros
     = Args.hasArg(OPT_code_completion_macros);

clang/lib/Frontend/FrontendActions.cpp

@@ -140,7 +140,7 @@ GeneratePCHAction::CreateOutputFile(CompilerInstance &CI, StringRef InFile,
   std::unique_ptr<raw_pwrite_stream> OS =
       CI.createOutputFile(CI.getFrontendOpts().OutputFile, /*Binary=*/true,
                           /*RemoveFileOnSignal=*/false, InFile,
-                          /*Extension=*/"", /*useTemporary=*/true);
+                          /*Extension=*/"", CI.getFrontendOpts().UseTemporary);
   if (!OS)
     return nullptr;
 

clang/test/Driver/clang_f_opts.c

@@ -571,3 +571,6 @@
 // CHECK-TRIVIAL-PATTERN-NOT: hasn't been enabled
 // CHECK-TRIVIAL-ZERO-GOOD-NOT: hasn't been enabled
 // CHECK-TRIVIAL-ZERO-BAD: hasn't been enabled
+
+// RUN: %clang -### -S -fno-temp-file %s 2>&1 | FileCheck -check-prefix=CHECK-NO-TEMP-FILE %s
+// CHECK-NO-TEMP-FILE: "-fno-temp-file"