From 273c299d5d649a0222fbde03c9a41e41913751b4 Mon Sep 17 00:00:00 2001 From: Vedant Kumar Date: Tue, 13 Oct 2020 21:35:29 +0000 Subject: [PM/CC1] Add -f[no-]split-cold-code CC1 option to toggle splitting This patch adds -f[no-]split-cold-code CC1 options to clang. This allows the splitting pass to be toggled on/off. The current method of passing `-mllvm -hot-cold-split=true` to clang isn't ideal as it may not compose correctly (say, with `-O0` or `-Oz`). To implement the -fsplit-cold-code option, an attribute is applied to functions to indicate that they may be considered for splitting. This removes some complexity from the old/new PM pipeline builders, and behaves as expected when LTO is enabled. Co-authored by: Saleem Abdulrasool Differential Revision: https://reviews.llvm.org/D57265 Reviewed By: Aditya Kumar, Vedant Kumar Reviewers: Teresa Johnson, Aditya Kumar, Fedor Sergeev, Philip Pfaffe, Vedant Kumar --- clang/lib/Frontend/CompilerInvocation.cpp | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'clang/lib/Frontend/CompilerInvocation.cpp') diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index a4c56cc..87d64f1 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -1469,6 +1469,17 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK, Opts.PassByValueIsNoAlias = Args.hasArg(OPT_fpass_by_value_is_noalias); + // -f[no-]split-cold-code + // This may only be enabled when optimizing, and when small code size + // increases are tolerable. + Opts.SplitColdCode = + (Opts.OptimizationLevel > 0) && (Opts.OptimizeSize != 2) && + Args.hasFlag(OPT_fsplit_cold_code, OPT_fno_split_cold_code, false); + if (Arg *A = Args.getLastArg(OPT_fsplit_cold_code)) + if (!Opts.SplitColdCode) + Diags.Report(diag::warn_fe_ignored_opt_split_cold_code) + << A->getAsString(Args) << (Opts.OptimizeSize != 2); + return Success; } -- cgit v1.1