Index: cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td =================================================================== --- cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td +++ cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td @@ -133,6 +133,7 @@ "invalid output type '%0' for use with gcc tool">; def err_drv_cc_print_options_failure : Error< "unable to open CC_PRINT_OPTIONS file: %0">; +def err_drv_lto_without_lld : Error<"LTO requires -fuse-ld=lld">; def err_drv_preamble_format : Error< "incorrect format for -preamble-bytes=N,END">; def err_drv_conflicting_deployment_targets : Error< Index: cfe/trunk/include/clang/Driver/Options.td =================================================================== --- cfe/trunk/include/clang/Driver/Options.td +++ cfe/trunk/include/clang/Driver/Options.td @@ -957,7 +957,7 @@ def flat__namespace : Flag<["-"], "flat_namespace">; def flax_vector_conversions : Flag<["-"], "flax-vector-conversions">, Group; def flimited_precision_EQ : Joined<["-"], "flimited-precision=">, Group; -def flto_EQ : Joined<["-"], "flto=">, Flags<[CC1Option]>, Group, +def flto_EQ : Joined<["-"], "flto=">, Flags<[CoreOption, CC1Option]>, Group, HelpText<"Set LTO mode to either 'full' or 'thin'">; def flto : Flag<["-"], "flto">, Flags<[CoreOption, CC1Option]>, Group, HelpText<"Enable LTO in 'full' mode">; Index: cfe/trunk/lib/Driver/Driver.cpp =================================================================== --- cfe/trunk/lib/Driver/Driver.cpp +++ cfe/trunk/lib/Driver/Driver.cpp @@ -2353,8 +2353,12 @@ Arg *FinalPhaseArg; phases::ID FinalPhase = getFinalPhase(Args, &FinalPhaseArg); - if (FinalPhase == phases::Link && Args.hasArg(options::OPT_emit_llvm)) { - Diag(clang::diag::err_drv_emit_llvm_link); + if (FinalPhase == phases::Link) { + if (Args.hasArg(options::OPT_emit_llvm)) + Diag(clang::diag::err_drv_emit_llvm_link); + if (IsCLMode() && LTOMode != LTOK_None && + !Args.getLastArgValue(options::OPT_fuse_ld_EQ).equals_lower("lld")) + Diag(clang::diag::err_drv_lto_without_lld); } // Reject -Z* at the top level, these options should never have been exposed Index: cfe/trunk/test/Driver/cl-options.c =================================================================== --- cfe/trunk/test/Driver/cl-options.c +++ cfe/trunk/test/Driver/cl-options.c @@ -522,6 +522,15 @@ // RUN: env CL="%s" _CL_="%s" not %clang --rsp-quoting=windows -c +// RUN: %clang_cl -### /c -flto -- %s 2>&1 | FileCheck -check-prefix=LTO %s +// LTO: -flto + +// RUN: %clang_cl -### /c -flto=thin -- %s 2>&1 | FileCheck -check-prefix=LTO-THIN %s +// LTO-THIN: -flto=thin + +// RUN: %clang_cl -### -Fe%t.exe -entry:main -flto -- %s 2>&1 | FileCheck -check-prefix=LTO-WITHOUT-LLD %s +// LTO-WITHOUT-LLD: LTO requires -fuse-ld=lld + // Accept "core" clang options. // (/Zs is for syntax-only, -Werror makes it fail hard on unknown options) // RUN: %clang_cl \