Author: dberris Date: Wed Nov 29 16:04:54 2017 New Revision: 319388 URL: http://llvm.org/viewvc/llvm-project?rev=319388&view=rev Log: [XRay][clang] Introduce -fxray-always-emit-customevents
Summary: The -fxray-always-emit-customevents flag instructs clang to always emit the LLVM IR for calls to the `__xray_customevent(...)` built-in function. The default behaviour currently respects whether the function has an `[[clang::xray_never_instrument]]` attribute, and thus not lower the appropriate IR code for the custom event built-in. This change allows users calling through to the `__xray_customevent(...)` built-in to always see those calls lowered to the corresponding LLVM IR to lay down instrumentation points for these custom event calls. Using this flag enables us to emit even just the user-provided custom events even while never instrumenting the start/end of the function where they appear. This is useful in cases where "phase markers" using __xray_customevent(...) can have very few instructions, must never be instrumented when entered/exited. Reviewers: rnk, dblaikie, kpw Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D40601 Added: cfe/trunk/test/CodeGen/xray-always-emit-customevent.cpp Modified: cfe/trunk/include/clang/Basic/LangOptions.def cfe/trunk/include/clang/Driver/Options.td cfe/trunk/include/clang/Driver/XRayArgs.h cfe/trunk/include/clang/Frontend/CodeGenOptions.def cfe/trunk/lib/CodeGen/CGBuiltin.cpp cfe/trunk/lib/CodeGen/CodeGenFunction.cpp cfe/trunk/lib/CodeGen/CodeGenFunction.h cfe/trunk/lib/Driver/XRayArgs.cpp cfe/trunk/lib/Frontend/CompilerInvocation.cpp Modified: cfe/trunk/include/clang/Basic/LangOptions.def URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/LangOptions.def?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/include/clang/Basic/LangOptions.def (original) +++ cfe/trunk/include/clang/Basic/LangOptions.def Wed Nov 29 16:04:54 2017 @@ -272,6 +272,9 @@ LANGOPT(SanitizeAddressFieldPadding, 2, "aggressive, 2: more aggressive)") LANGOPT(XRayInstrument, 1, 0, "controls whether to do XRay instrumentation") +LANGOPT(XRayAlwaysEmitCustomEvents, 1, 0, + "controls whether to always emit intrinsic calls to " + "__xray_customevent(...) builtin.") BENIGN_LANGOPT(AllowEditorPlaceholders, 1, 0, "allow editor placeholders in source") Modified: cfe/trunk/include/clang/Driver/Options.td URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/include/clang/Driver/Options.td (original) +++ cfe/trunk/include/clang/Driver/Options.td Wed Nov 29 16:04:54 2017 @@ -1060,6 +1060,12 @@ def fxray_never_instrument : Group<f_Group>, Flags<[CC1Option]>, HelpText<"Filename defining the whitelist for imbuing the 'never instrument' XRay attribute.">; +def fxray_always_emit_customevents : Flag<["-"], "fxray-always-emit-customevents">, Group<f_Group>, + Flags<[CC1Option]>, + HelpText<"Determine whether to always emit __xray_customevent(...) calls even if the function it appears in is not always instrumented.">; +def fnoxray_always_emit_customevents : Flag<["-"], "fno-xray-always-emit-customevents">, Group<f_Group>, + Flags<[CC1Option]>; + def ffine_grained_bitfield_accesses : Flag<["-"], "ffine-grained-bitfield-accesses">, Group<f_clang_Group>, Flags<[CC1Option]>, HelpText<"Use separate accesses for bitfields with legal widths and alignments.">; Modified: cfe/trunk/include/clang/Driver/XRayArgs.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/XRayArgs.h?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/include/clang/Driver/XRayArgs.h (original) +++ cfe/trunk/include/clang/Driver/XRayArgs.h Wed Nov 29 16:04:54 2017 @@ -24,6 +24,7 @@ class XRayArgs { std::vector<std::string> ExtraDeps; bool XRayInstrument = false; int InstructionThreshold = 200; + bool XRayAlwaysEmitCustomEvents = false; public: /// Parses the XRay arguments from an argument list. Modified: cfe/trunk/include/clang/Frontend/CodeGenOptions.def URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/CodeGenOptions.def?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/include/clang/Frontend/CodeGenOptions.def (original) +++ cfe/trunk/include/clang/Frontend/CodeGenOptions.def Wed Nov 29 16:04:54 2017 @@ -84,6 +84,9 @@ CODEGENOPT(InstrumentFunctionEntryBare , CODEGENOPT(XRayInstrumentFunctions , 1, 0) ///< Set when -fxray-instrument is ///< enabled. +///< Set when -fxray-always-emit-customevents is enabled. +CODEGENOPT(XRayAlwaysEmitCustomEvents , 1, 0) + ///< Set the minimum number of instructions in a function to determine selective ///< XRay instrumentation. VALUE_CODEGENOPT(XRayInstructionThreshold , 32, 200) Modified: cfe/trunk/lib/CodeGen/CGBuiltin.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGBuiltin.cpp?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CGBuiltin.cpp (original) +++ cfe/trunk/lib/CodeGen/CGBuiltin.cpp Wed Nov 29 16:04:54 2017 @@ -3003,10 +3003,10 @@ RValue CodeGenFunction::EmitBuiltinExpr( case Builtin::BI__xray_customevent: { if (!ShouldXRayInstrumentFunction()) return RValue::getIgnored(); - if (const auto *XRayAttr = CurFuncDecl->getAttr<XRayInstrumentAttr>()) { - if (XRayAttr->neverXRayInstrument()) + if (const auto *XRayAttr = CurFuncDecl->getAttr<XRayInstrumentAttr>()) + if (XRayAttr->neverXRayInstrument() && !AlwaysEmitXRayCustomEvents()) return RValue::getIgnored(); - } + Function *F = CGM.getIntrinsic(Intrinsic::xray_customevent); auto FTy = F->getFunctionType(); auto Arg0 = E->getArg(0); Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original) +++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Wed Nov 29 16:04:54 2017 @@ -458,6 +458,12 @@ bool CodeGenFunction::ShouldXRayInstrume return CGM.getCodeGenOpts().XRayInstrumentFunctions; } +/// AlwaysEmitXRayCustomEvents - Return true if we should emit IR for calls to +/// the __xray_customevent(...) builin calls, when doing XRay instrumentation. +bool CodeGenFunction::AlwaysEmitXRayCustomEvents() const { + return CGM.getCodeGenOpts().XRayAlwaysEmitCustomEvents; +} + llvm::Constant * CodeGenFunction::EncodeAddrForUseInPrologue(llvm::Function *F, llvm::Constant *Addr) { Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original) +++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Wed Nov 29 16:04:54 2017 @@ -1771,6 +1771,10 @@ public: /// instrumented with XRay nop sleds. bool ShouldXRayInstrumentFunction() const; + /// AlwaysEmitXRayCustomEvents - Return true if we must unconditionally emit + /// XRay custom event handling calls. + bool AlwaysEmitXRayCustomEvents() const; + /// Encode an address into a form suitable for use in a function prologue. llvm::Constant *EncodeAddrForUseInPrologue(llvm::Function *F, llvm::Constant *Addr); Modified: cfe/trunk/lib/Driver/XRayArgs.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/XRayArgs.cpp?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/lib/Driver/XRayArgs.cpp (original) +++ cfe/trunk/lib/Driver/XRayArgs.cpp Wed Nov 29 16:04:54 2017 @@ -27,8 +27,6 @@ namespace { constexpr char XRayInstrumentOption[] = "-fxray-instrument"; constexpr char XRayInstructionThresholdOption[] = "-fxray-instruction-threshold="; -constexpr char XRayAlwaysInstrumentOption[] = "-fxray-always-instrument="; -constexpr char XRayNeverInstrumentOption[] = "-fxray-never-instrument="; } // namespace XRayArgs::XRayArgs(const ToolChain &TC, const ArgList &Args) { @@ -63,6 +61,14 @@ XRayArgs::XRayArgs(const ToolChain &TC, D.Diag(clang::diag::err_drv_invalid_value) << A->getAsString(Args) << S; } + // By default, the back-end will not emit the lowering for XRay customevent + // calls if the function is not instrumented. In the future we will change + // this default to be the reverse, but in the meantime we're going to + // introduce the new functionality behind a flag. + if (Args.hasFlag(options::OPT_fxray_always_emit_customevents, + options::OPT_fnoxray_always_emit_customevents, false)) + XRayAlwaysEmitCustomEvents = true; + // Validate the always/never attribute files. We also make sure that they // are treated as actual dependencies. for (const auto &Filename : @@ -91,17 +97,21 @@ void XRayArgs::addArgs(const ToolChain & return; CmdArgs.push_back(XRayInstrumentOption); + + if (XRayAlwaysEmitCustomEvents) + CmdArgs.push_back("-fxray-always-emit-customevents"); + CmdArgs.push_back(Args.MakeArgString(Twine(XRayInstructionThresholdOption) + Twine(InstructionThreshold))); for (const auto &Always : AlwaysInstrumentFiles) { - SmallString<64> AlwaysInstrumentOpt(XRayAlwaysInstrumentOption); + SmallString<64> AlwaysInstrumentOpt("-fxray-always-instrument="); AlwaysInstrumentOpt += Always; CmdArgs.push_back(Args.MakeArgString(AlwaysInstrumentOpt)); } for (const auto &Never : NeverInstrumentFiles) { - SmallString<64> NeverInstrumentOpt(XRayNeverInstrumentOption); + SmallString<64> NeverInstrumentOpt("-fxray-never-instrument="); NeverInstrumentOpt += Never; CmdArgs.push_back(Args.MakeArgString(NeverInstrumentOpt)); } Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=319388&r1=319387&r2=319388&view=diff ============================================================================== --- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original) +++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Wed Nov 29 16:04:54 2017 @@ -785,6 +785,8 @@ static bool ParseCodeGenArgs(CodeGenOpti Opts.InstrumentFunctionEntryBare = Args.hasArg(OPT_finstrument_function_entry_bare); Opts.XRayInstrumentFunctions = Args.hasArg(OPT_fxray_instrument); + Opts.XRayAlwaysEmitCustomEvents = + Args.hasArg(OPT_fxray_always_emit_customevents); Opts.XRayInstructionThreshold = getLastArgIntValue(Args, OPT_fxray_instruction_threshold_EQ, 200, Diags); Opts.InstrumentForProfiling = Args.hasArg(OPT_pg); @@ -2503,6 +2505,11 @@ static void ParseLangArgs(LangOptions &O Opts.XRayInstrument = Args.hasFlag(OPT_fxray_instrument, OPT_fnoxray_instrument, false); + // -fxray-always-emit-customevents + Opts.XRayAlwaysEmitCustomEvents = + Args.hasFlag(OPT_fxray_always_emit_customevents, + OPT_fnoxray_always_emit_customevents, false); + // -fxray-{always,never}-instrument= filenames. Opts.XRayAlwaysInstrumentFiles = Args.getAllArgValues(OPT_fxray_always_instrument); Added: cfe/trunk/test/CodeGen/xray-always-emit-customevent.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/xray-always-emit-customevent.cpp?rev=319388&view=auto ============================================================================== --- cfe/trunk/test/CodeGen/xray-always-emit-customevent.cpp (added) +++ cfe/trunk/test/CodeGen/xray-always-emit-customevent.cpp Wed Nov 29 16:04:54 2017 @@ -0,0 +1,10 @@ +// RUN: %clang_cc1 -fxray-instrument -fxray-always-emit-customevents -x c++ \ +// RUN: -std=c++11 -triple x86_64-unknown-unknown -emit-llvm -o - %s \ +// RUN: | FileCheck %s + +// CHECK-LABEL: @_Z15neverInstrumentv +[[clang::xray_never_instrument]] void neverInstrument() { + static constexpr char kPhase[] = "never"; + __xray_customevent(kPhase, 5); + // CHECK: call void @llvm.xray.customevent(i8*{{.*}}, i32 5) +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
