Index: test/Frontend/fpredictive-compilation.c =================================================================== --- test/Frontend/fpredictive-compilation.c (revision 0) +++ test/Frontend/fpredictive-compilation.c (revision 0) @@ -0,0 +1,4 @@ +// RUN: echo 'itn a;' | %clang -fpredictive-compilation %s -o - 2>&1 | FileCheck -check-prefix=RUN1 %s +// CHECK-RUN1: fpredictive-compilation.c:1:1: error: unknown type name 'itn' +// RUN: echo 'itn a;' | %clang -fpredictive-compilation=0 %s -o - 2>&1 | FileCheck -check-prefix=RUN2 %s +// CHECK-RUN2: fpredictive-compilation.c:1:1: error: unknown type name 'itn' Index: include/clang/Frontend/FrontendOptions.h =================================================================== --- include/clang/Frontend/FrontendOptions.h (revision 139582) +++ include/clang/Frontend/FrontendOptions.h (working copy) @@ -123,6 +123,11 @@ /// should only be used for debugging and experimental features. std::vector LLVMArgs; + /// If this is non-empty, |Inputs| is used to determine input language and + /// default |OutputFile| contents, but the actual compiler input is read from + /// stdin. + std::string PredictiveCompilation; + public: FrontendOptions() { DisableFree = 0; Index: include/clang/Frontend/DiagnosticOptions.h =================================================================== --- include/clang/Frontend/DiagnosticOptions.h (revision 139582) +++ include/clang/Frontend/DiagnosticOptions.h (working copy) @@ -72,6 +72,10 @@ /// prefixes removed. std::vector Warnings; + /// If non-empty, diagnostics for the main file are reported for this filename + /// instead. + std::string FakeDiagMainFile; + public: DiagnosticOptions() { IgnoreWarnings = 0; Index: include/clang/Driver/CC1Options.td =================================================================== --- include/clang/Driver/CC1Options.td (revision 139582) +++ include/clang/Driver/CC1Options.td (working copy) @@ -542,6 +542,8 @@ HelpText<"Support POSIX threads in generated code">; def fpascal_strings : Flag<"-fpascal-strings">, HelpText<"Recognize and construct Pascal-style string literals">; +def fpredictive_compilation : Separate<"-fpredictive-compilation">, + HelpText<"Read compiler input from stdin, but still require an input filename">; def fno_rtti : Flag<"-fno-rtti">, HelpText<"Disable generation of rtti information">; def fno_validate_pch : Flag<"-fno-validate-pch">, Index: include/clang/Driver/Options.td =================================================================== --- include/clang/Driver/Options.td (revision 139582) +++ include/clang/Driver/Options.td (working copy) @@ -436,6 +436,8 @@ def fpic : Flag<"-fpic">, Group; def fpie : Flag<"-fpie">, Group, Flags<[NoArgumentUnused]>; def fno_pie : Flag<"-fno-pie">, Group, Flags<[NoArgumentUnused]>; +def fpredictive_compilation_def : Flag<"-fpredictive-compilation">, Group; +def fpredictive_compilation_EQ : Joined<"-fpredictive-compilation=">, Group; def fprofile_arcs : Flag<"-fprofile-arcs">, Group; def fprofile_generate : Flag<"-fprofile-generate">, Group; def framework : Separate<"-framework">, Flags<[LinkerInput]>; Index: lib/Frontend/CompilerInstance.cpp =================================================================== --- lib/Frontend/CompilerInstance.cpp (revision 139582) +++ lib/Frontend/CompilerInstance.cpp (working copy) @@ -531,7 +531,7 @@ // been created (e.g., by a precompiled preamble). if (!SourceMgr.getMainFileID().isInvalid()) { // Do nothing: the main file has already been set. - } else if (InputFile != "-") { + } else if (InputFile != "-" && Opts.PredictiveCompilation.empty()) { const FileEntry *File = FileMgr.getFile(InputFile); if (!File) { Diags.Report(diag::err_fe_error_reading) << InputFile; Index: lib/Frontend/CompilerInvocation.cpp =================================================================== --- lib/Frontend/CompilerInvocation.cpp (revision 139582) +++ lib/Frontend/CompilerInvocation.cpp (working copy) @@ -502,6 +502,10 @@ Res.push_back("-mllvm"); Res.push_back(Opts.LLVMArgs[i]); } + if (!Opts.PredictiveCompilation.empty()) { + Res.push_back("-fpredictive-compilation"); + Res.push_back(Opts.PredictiveCompilation); + } } static void HeaderSearchOptsToArgs(const HeaderSearchOptions &Opts, @@ -1281,6 +1285,8 @@ Opts.ShowVersion = Args.hasArg(OPT_version); Opts.ASTMergeFiles = Args.getAllArgValues(OPT_ast_merge); Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm); + Opts.PredictiveCompilation + = Args.getLastArgValue(OPT_fpredictive_compilation); Opts.FixWhatYouCan = Args.hasArg(OPT_fix_what_you_can); Opts.ARCMTAction = FrontendOptions::ARCMT_None; @@ -1913,4 +1919,11 @@ ParsePreprocessorArgs(Res.getPreprocessorOpts(), *Args, FileMgr, Diags); ParsePreprocessorOutputArgs(Res.getPreprocessorOutputOpts(), *Args); ParseTargetArgs(Res.getTargetOpts(), *Args); + + // With -fpredictive-compilation, main file errors are reported not for + // but for the input file, even though the input is read from stdin. + if (!Res.getFrontendOpts().PredictiveCompilation.empty()) { + Res.getDiagnosticOpts().FakeDiagMainFile + = Res.getFrontendOpts().Inputs[0].second; + } } Index: lib/Frontend/TextDiagnosticPrinter.cpp =================================================================== --- lib/Frontend/TextDiagnosticPrinter.cpp (revision 139582) +++ lib/Frontend/TextDiagnosticPrinter.cpp (working copy) @@ -954,17 +954,23 @@ PresumedLoc PLoc) { if (PLoc.isInvalid()) { // At least print the file name if available: - FileID FID = SM.getFileID(Info.getLocation()); - if (!FID.isInvalid()) { - const FileEntry* FE = SM.getFileEntryForID(FID); - if (FE && FE->getName()) { - OS << FE->getName(); - if (FE->getDevice() == 0 && FE->getInode() == 0 - && FE->getFileMode() == 0) { - // in PCH is a guess, but a good one: - OS << " (in PCH)"; + if (SM.isFromMainFile(Info.getLocation()) && + DiagOpts->FakeDiagMainFile.size()) { + // Use original input file name, even though we're reading from stdin. + OS << DiagOpts->FakeDiagMainFile << ": "; + } else { + FileID FID = SM.getFileID(Info.getLocation()); + if (!FID.isInvalid()) { + const FileEntry* FE = SM.getFileEntryForID(FID); + if (FE && FE->getName()) { + OS << FE->getName(); + if (FE->getDevice() == 0 && FE->getInode() == 0 + && FE->getFileMode() == 0) { + // in PCH is a guess, but a good one: + OS << " (in PCH)"; + } + OS << ": "; } - OS << ": "; } } return; @@ -977,7 +983,13 @@ if (DiagOpts->ShowColors) OS.changeColor(savedColor, true); - OS << PLoc.getFilename(); + if (SM.isFromMainFile(Info.getLocation()) && + DiagOpts->FakeDiagMainFile.size()) { + // Use original input file name, even though we're reading from stdin. + OS << DiagOpts->FakeDiagMainFile; + } else { + OS << PLoc.getFilename(); + } switch (DiagOpts->Format) { case DiagnosticOptions::Clang: OS << ':' << LineNo; break; case DiagnosticOptions::Msvc: OS << '(' << LineNo; break; Index: lib/Driver/Tools.cpp =================================================================== --- lib/Driver/Tools.cpp (revision 139582) +++ lib/Driver/Tools.cpp (working copy) @@ -2022,6 +2022,25 @@ CmdArgs.push_back(A->getValue(Args)); } + if (Arg *A = Args.getLastArg(options::OPT_Wlarge_by_value_copy_EQ, + options::OPT_Wlarge_by_value_copy_def)) { + CmdArgs.push_back("-Wlarge-by-value-copy"); + if (A->getNumValues()) + CmdArgs.push_back(A->getValue(Args)); + else + CmdArgs.push_back("64"); // default value for -Wlarge-by-value-copy. + } + + if (const Arg *A = + Args.getLastArg(options::OPT_fpredictive_compilation_EQ, + options::OPT_fpredictive_compilation_def)) { + CmdArgs.push_back("-fpredictive-compilation"); + if (A->getNumValues()) + CmdArgs.push_back(A->getValue(Args)); + else + CmdArgs.push_back("0"); + } + if (Arg *A = Args.getLastArg( options::OPT_fdiagnostics_show_note_include_stack, options::OPT_fno_diagnostics_show_note_include_stack)) {