Author: tmsriram Date: Tue Nov 7 11:37:51 2017 New Revision: 317605 URL: http://llvm.org/viewvc/llvm-project?rev=317605&view=rev Log: New clang option -fno-plt which avoids the PLT and lazy binding while making external calls.
Differential Revision: https://reviews.llvm.org/D39079 Added: cfe/trunk/test/CodeGen/noplt.c Modified: cfe/trunk/include/clang/Driver/Options.td cfe/trunk/include/clang/Frontend/CodeGenOptions.def cfe/trunk/lib/CodeGen/CGCall.cpp cfe/trunk/lib/Driver/ToolChains/Clang.cpp cfe/trunk/lib/Frontend/CompilerInvocation.cpp Modified: cfe/trunk/include/clang/Driver/Options.td URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=317605&r1=317604&r2=317605&view=diff ============================================================================== --- cfe/trunk/include/clang/Driver/Options.td (original) +++ cfe/trunk/include/clang/Driver/Options.td Tue Nov 7 11:37:51 2017 @@ -1384,6 +1384,10 @@ def fpic : Flag<["-"], "fpic">, Group<f_ def fno_pic : Flag<["-"], "fno-pic">, Group<f_Group>; def fpie : Flag<["-"], "fpie">, Group<f_Group>; def fno_pie : Flag<["-"], "fno-pie">, Group<f_Group>; +def fplt : Flag<["-"], "fplt">, Group<f_Group>, Flags<[CC1Option]>, + HelpText<"Use the PLT to make function calls">; +def fno_plt : Flag<["-"], "fno-plt">, Group<f_Group>, Flags<[CC1Option]>, + HelpText<"Do not use the PLT to make function calls">; def fropi : Flag<["-"], "fropi">, Group<f_Group>; def fno_ropi : Flag<["-"], "fno-ropi">, Group<f_Group>; def frwpi : Flag<["-"], "frwpi">, Group<f_Group>; Modified: cfe/trunk/include/clang/Frontend/CodeGenOptions.def URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/CodeGenOptions.def?rev=317605&r1=317604&r2=317605&view=diff ============================================================================== --- cfe/trunk/include/clang/Frontend/CodeGenOptions.def (original) +++ cfe/trunk/include/clang/Frontend/CodeGenOptions.def Tue Nov 7 11:37:51 2017 @@ -297,6 +297,8 @@ CODEGENOPT(PreserveVec3Type, 1, 0) /// Whether to emit .debug_gnu_pubnames section instead of .debug_pubnames. CODEGENOPT(GnuPubnames, 1, 0) +CODEGENOPT(NoPLT, 1, 0) + #undef CODEGENOPT #undef ENUM_CODEGENOPT #undef VALUE_CODEGENOPT Modified: cfe/trunk/lib/CodeGen/CGCall.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCall.cpp?rev=317605&r1=317604&r2=317605&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CGCall.cpp (original) +++ cfe/trunk/lib/CodeGen/CGCall.cpp Tue Nov 7 11:37:51 2017 @@ -1855,6 +1855,16 @@ void CodeGenModule::ConstructAttributeLi !(TargetDecl && TargetDecl->hasAttr<NoSplitStackAttr>())) FuncAttrs.addAttribute("split-stack"); + // Add NonLazyBind attribute to function declarations when -fno-plt + // is used. + if (TargetDecl && CodeGenOpts.NoPLT) { + if (auto *Fn = dyn_cast<FunctionDecl>(TargetDecl)) { + if (!Fn->isDefined() && !AttrOnCallSite) { + FuncAttrs.addAttribute(llvm::Attribute::NonLazyBind); + } + } + } + if (!AttrOnCallSite) { bool DisableTailCalls = CodeGenOpts.DisableTailCalls || Modified: cfe/trunk/lib/Driver/ToolChains/Clang.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains/Clang.cpp?rev=317605&r1=317604&r2=317605&view=diff ============================================================================== --- cfe/trunk/lib/Driver/ToolChains/Clang.cpp (original) +++ cfe/trunk/lib/Driver/ToolChains/Clang.cpp Tue Nov 7 11:37:51 2017 @@ -3423,6 +3423,10 @@ void Clang::ConstructJob(Compilation &C, CmdArgs.push_back("-mpie-copy-relocations"); } + if (Args.hasFlag(options::OPT_fno_plt, options::OPT_fplt, false)) { + CmdArgs.push_back("-fno-plt"); + } + // -fhosted is default. // TODO: Audit uses of KernelOrKext and see where it'd be more appropriate to // use Freestanding. Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=317605&r1=317604&r2=317605&view=diff ============================================================================== --- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original) +++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Tue Nov 7 11:37:51 2017 @@ -653,6 +653,7 @@ static bool ParseCodeGenArgs(CodeGenOpti Args.hasArg(OPT_mincremental_linker_compatible); Opts.PIECopyRelocations = Args.hasArg(OPT_mpie_copy_relocations); + Opts.NoPLT = Args.hasArg(OPT_fno_plt); Opts.OmitLeafFramePointer = Args.hasArg(OPT_momit_leaf_frame_pointer); Opts.SaveTempLabels = Args.hasArg(OPT_msave_temp_labels); Opts.NoDwarfDirectoryAsm = Args.hasArg(OPT_fno_dwarf_directory_asm); Added: cfe/trunk/test/CodeGen/noplt.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/noplt.c?rev=317605&view=auto ============================================================================== --- cfe/trunk/test/CodeGen/noplt.c (added) +++ cfe/trunk/test/CodeGen/noplt.c Tue Nov 7 11:37:51 2017 @@ -0,0 +1,9 @@ +// RUN: %clang_cc1 -emit-llvm -fno-plt %s -o - | FileCheck %s -check-prefix=CHECK-NOPLT + +// CHECK-NOPLT: Function Attrs: nonlazybind +// CHECK-NOPLT-NEXT: declare i32 @foo +int foo(); + +int bar() { + return foo(); +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
