r275330 - Add XRay flags to Clang. We implement two flags to control the XRay behaviour:
Aaron Ballman via cfe-commits
cfe-commits at lists.llvm.org
Wed Jul 13 15:32:15 PDT 2016
Author: aaronballman
Date: Wed Jul 13 17:32:15 2016
New Revision: 275330
URL: http://llvm.org/viewvc/llvm-project?rev=275330&view=rev
Log:
Add XRay flags to Clang. We implement two flags to control the XRay behaviour:
-fxray-instrument: enables XRay annotation of IR
-fxray-instruction-threshold: configures the threshold for function size (looking at IR instructions), and allow LLVM to decide whether to add the nop sleds later on in the process.
Also implements the related xray_always_instrument and xray_never_instrument function attributes.
Patch by Dean Michael Berris.
Added:
cfe/trunk/test/CodeGen/xray-attributes-supported.cpp
cfe/trunk/test/Sema/xray-always-instrument-attr.c
cfe/trunk/test/Sema/xray-always-instrument-attr.cpp
Modified:
cfe/trunk/include/clang/Basic/Attr.td
cfe/trunk/include/clang/Basic/AttrDocs.td
cfe/trunk/include/clang/Driver/Options.td
cfe/trunk/include/clang/Frontend/CodeGenOptions.def
cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
cfe/trunk/lib/CodeGen/CodeGenFunction.h
cfe/trunk/lib/Driver/Tools.cpp
cfe/trunk/lib/Frontend/CompilerInvocation.cpp
cfe/trunk/lib/Sema/SemaDeclAttr.cpp
Modified: cfe/trunk/include/clang/Basic/Attr.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Attr.td?rev=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/Attr.td (original)
+++ cfe/trunk/include/clang/Basic/Attr.td Wed Jul 13 17:32:15 2016
@@ -428,6 +428,22 @@ def AlwaysInline : InheritableAttr {
let Documentation = [Undocumented];
}
+def XRayInstrument : InheritableAttr {
+ let Spellings = [GNU<"xray_always_instrument">,
+ CXX11<"clang", "xray_always_instrument">,
+ GNU<"xray_never_instrument">,
+ CXX11<"clang", "xray_never_instrument">];
+ let Subjects = SubjectList<[CXXMethod, ObjCMethod, Function], WarnDiag,
+ "ExpectedFunctionOrMethod">;
+ let Accessors = [Accessor<"alwaysXRayInstrument",
+ [GNU<"xray_always_instrument">,
+ CXX11<"clang", "xray_always_instrument">]>,
+ Accessor<"neverXRayInstrument",
+ [GNU<"xray_never_instrument">,
+ CXX11<"clang", "xray_never_instrument">]>];
+ let Documentation = [XRayDocs];
+}
+
def TLSModel : InheritableAttr {
let Spellings = [GCC<"tls_model">];
let Subjects = SubjectList<[TLSVar], ErrorDiag, "ExpectedTLSVar">;
Modified: cfe/trunk/include/clang/Basic/AttrDocs.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/AttrDocs.td?rev=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/AttrDocs.td (original)
+++ cfe/trunk/include/clang/Basic/AttrDocs.td Wed Jul 13 17:32:15 2016
@@ -2450,3 +2450,14 @@ See the RenderScript_ documentation for
.. _RenderScript: https://developer.android.com/guide/topics/renderscript/compute.html
}];
}
+
+def XRayDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+``__attribute__((xray_always_instrument))`` or ``[[clang:xray_always_instrument]]`` is used to mark member functions (in C++), methods (in Objective C), and free functions (in C, C++, and Objective C) to be instrumented with XRay. This will cause the function to always have space at the beginning and exit points to allow for runtime patching.
+
+Conversely, ``__attribute__((xray_never_instrument))`` or ``[[clang:xray_never_instrument]]`` will inhibit the insertion of these instrumentation points.
+
+If a function has neither of these attributes, they become subject to the XRay heuristics used to determine whether a function should be instrumented or otherwise.
+ }];
+}
Modified: cfe/trunk/include/clang/Driver/Options.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/Options.td (original)
+++ cfe/trunk/include/clang/Driver/Options.td Wed Jul 13 17:32:15 2016
@@ -781,6 +781,21 @@ def finput_charset_EQ : Joined<["-"], "f
def fexec_charset_EQ : Joined<["-"], "fexec-charset=">, Group<f_Group>;
def finstrument_functions : Flag<["-"], "finstrument-functions">, Group<f_Group>, Flags<[CC1Option]>,
HelpText<"Generate calls to instrument function entry and exit">;
+
+def fxray_instrument : Flag<["-"], "fxray-instrument">, Group<f_Group>,
+ Flags<[CC1Option]>,
+ HelpText<"Generate XRay instrumentation sleds on function entry and exit">;
+def fnoxray_instrument : Flag<["-"], "fno-xray-instrument">, Group<f_Group>,
+ Flags<[CC1Option]>;
+
+def fxray_instruction_threshold_EQ :
+ JoinedOrSeparate<["-"], "fxray-instruction-threshold=">,
+ Group<f_Group>, Flags<[CC1Option]>,
+ HelpText<"Sets the minimum function size to instrument with XRay">;
+def fxray_instruction_threshold_ :
+ JoinedOrSeparate<["-"], "fxray-instruction-threshold">,
+ Group<f_Group>, Flags<[CC1Option]>;
+
def flat__namespace : Flag<["-"], "flat_namespace">;
def flax_vector_conversions : Flag<["-"], "flax-vector-conversions">, Group<f_Group>;
def flimited_precision_EQ : Joined<["-"], "flimited-precision=">, 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=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/include/clang/Frontend/CodeGenOptions.def (original)
+++ cfe/trunk/include/clang/Frontend/CodeGenOptions.def Wed Jul 13 17:32:15 2016
@@ -74,6 +74,14 @@ CODEGENOPT(ForbidGuardVariables , 1, 0)
CODEGENOPT(FunctionSections , 1, 0) ///< Set when -ffunction-sections is enabled.
CODEGENOPT(InstrumentFunctions , 1, 0) ///< Set when -finstrument-functions is
///< enabled.
+
+CODEGENOPT(XRayInstrumentFunctions , 1, 0) ///< Set when -fxray-instrument is
+ ///< enabled.
+
+///< Set the minimum number of instructions in a function to determine selective
+///< XRay instrumentation.
+VALUE_CODEGENOPT(XRayInstructionThreshold , 32, 200)
+
CODEGENOPT(InstrumentForProfiling , 1, 0) ///< Set when -pg is enabled.
CODEGENOPT(LessPreciseFPMAD , 1, 0) ///< Enable less precise MAD instructions to
///< be generated.
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Wed Jul 13 17:32:15 2016
@@ -397,6 +397,12 @@ bool CodeGenFunction::ShouldInstrumentFu
return true;
}
+/// ShouldXRayInstrument - Return true if the current function should be
+/// instrumented with XRay nop sleds.
+bool CodeGenFunction::ShouldXRayInstrumentFunction() const {
+ return CGM.getCodeGenOpts().XRayInstrumentFunctions;
+}
+
/// EmitFunctionInstrumentation - Emit LLVM code to call the specified
/// instrumentation function with the current function and the call site, if
/// function instrumentation is enabled.
@@ -686,6 +692,20 @@ void CodeGenFunction::StartFunction(Glob
if (SanOpts.has(SanitizerKind::SafeStack))
Fn->addFnAttr(llvm::Attribute::SafeStack);
+ // Apply xray attributes to the function (as a string, for now)
+ if (D && ShouldXRayInstrumentFunction()) {
+ if (const auto *XRayAttr = D->getAttr<XRayInstrumentAttr>()) {
+ if (XRayAttr->alwaysXRayInstrument())
+ Fn->addFnAttr("function-instrument", "xray-always");
+ if (XRayAttr->neverXRayInstrument())
+ Fn->addFnAttr("function-instrument", "xray-never");
+ } else {
+ Fn->addFnAttr(
+ "xray-instruction-threshold",
+ llvm::itostr(CGM.getCodeGenOpts().XRayInstructionThreshold));
+ }
+ }
+
// Pass inline keyword to optimizer if it appears explicitly on any
// declaration. Also, in the case of -fno-inline attach NoInline
// attribute to all functions that are not marked AlwaysInline, or
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Wed Jul 13 17:32:15 2016
@@ -1521,6 +1521,10 @@ public:
/// instrumented with __cyg_profile_func_* calls
bool ShouldInstrumentFunction();
+ /// ShouldXRayInstrument - Return true if the current function should be
+ /// instrumented with XRay nop sleds.
+ bool ShouldXRayInstrumentFunction() const;
+
/// EmitFunctionInstrumentation - Emit LLVM code to call the specified
/// instrumentation function with the current function and the call site, if
/// function instrumentation is enabled.
Modified: cfe/trunk/lib/Driver/Tools.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/Tools.cpp (original)
+++ cfe/trunk/lib/Driver/Tools.cpp Wed Jul 13 17:32:15 2016
@@ -3181,6 +3181,28 @@ static bool addSanitizerRuntimes(const T
return !StaticRuntimes.empty();
}
+static bool addXRayRuntime(const ToolChain &TC, const ArgList &Args,
+ ArgStringList &CmdArgs) {
+ if (Args.hasFlag(options::OPT_fxray_instrument,
+ options::OPT_fnoxray_instrument, false)) {
+ CmdArgs.push_back("-whole-archive");
+ CmdArgs.push_back(TC.getCompilerRTArgString(Args, "xray", false));
+ CmdArgs.push_back("-no-whole-archive");
+ return true;
+ }
+ return false;
+}
+
+static void linkXRayRuntimeDeps(const ToolChain &TC, ArgStringList &CmdArgs) {
+ CmdArgs.push_back("--no-as-needed");
+ CmdArgs.push_back("-lpthread");
+ CmdArgs.push_back("-lrt");
+ CmdArgs.push_back("-lm");
+ CmdArgs.push_back("-latomic");
+ if (TC.getTriple().getOS() != llvm::Triple::FreeBSD)
+ CmdArgs.push_back("-ldl");
+}
+
static bool areOptimizationsEnabled(const ArgList &Args) {
// Find the last -O arg and see if it is non-zero.
if (Arg *A = Args.getLastArg(options::OPT_O_Group))
@@ -4582,6 +4604,17 @@ void Clang::ConstructJob(Compilation &C,
Args.AddAllArgs(CmdArgs, options::OPT_finstrument_functions);
+ if (Args.hasFlag(options::OPT_fxray_instrument,
+ options::OPT_fnoxray_instrument, false)) {
+ CmdArgs.push_back("-fxray-instrument");
+ if (const Arg *A =
+ Args.getLastArg(options::OPT_fxray_instruction_threshold_,
+ options::OPT_fxray_instruction_threshold_EQ)) {
+ CmdArgs.push_back("-fxray-instruction-threshold");
+ CmdArgs.push_back(A->getValue());
+ }
+ }
+
addPGOAndCoverageFlags(C, D, Output, Args, CmdArgs);
// Add runtime flag for PS4 when PGO or Coverage are enabled.
@@ -9390,6 +9423,7 @@ void gnutools::Linker::ConstructJob(Comp
CmdArgs.push_back("--no-demangle");
bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
+ bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs);
// The profile runtime also needs access to system libraries.
getToolChain().addProfileRTLibs(Args, CmdArgs);
@@ -9416,6 +9450,9 @@ void gnutools::Linker::ConstructJob(Comp
if (NeedsSanitizerDeps)
linkSanitizerRuntimeDeps(ToolChain, CmdArgs);
+ if (NeedsXRayDeps)
+ linkXRayRuntimeDeps(ToolChain, CmdArgs);
+
bool WantPthread = Args.hasArg(options::OPT_pthread) ||
Args.hasArg(options::OPT_pthreads);
Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original)
+++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Wed Jul 13 17:32:15 2016
@@ -687,6 +687,9 @@ static bool ParseCodeGenArgs(CodeGenOpti
}
Opts.InstrumentFunctions = Args.hasArg(OPT_finstrument_functions);
+ Opts.XRayInstrumentFunctions = Args.hasArg(OPT_fxray_instrument);
+ Opts.XRayInstructionThreshold =
+ getLastArgIntValue(Args, OPT_fxray_instruction_threshold_, 200, Diags);
Opts.InstrumentForProfiling = Args.hasArg(OPT_pg);
Opts.EmitOpenCLArgMetadata = Args.hasArg(OPT_cl_kernel_arg_info);
Opts.CompressDebugSections = Args.hasArg(OPT_compress_debug_sections);
Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=275330&r1=275329&r2=275330&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Wed Jul 13 17:32:15 2016
@@ -5909,10 +5909,13 @@ static void ProcessDeclAttribute(Sema &S
case AttributeList::AT_TypeTagForDatatype:
handleTypeTagForDatatypeAttr(S, D, Attr);
break;
-
case AttributeList::AT_RenderScriptKernel:
handleSimpleAttribute<RenderScriptKernelAttr>(S, D, Attr);
break;
+ // XRay attributes.
+ case AttributeList::AT_XRayInstrument:
+ handleSimpleAttribute<XRayInstrumentAttr>(S, D, Attr);
+ break;
}
}
Added: cfe/trunk/test/CodeGen/xray-attributes-supported.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/xray-attributes-supported.cpp?rev=275330&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/xray-attributes-supported.cpp (added)
+++ cfe/trunk/test/CodeGen/xray-attributes-supported.cpp Wed Jul 13 17:32:15 2016
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - -triple x86_64-unknown-linux-gnu | FileCheck %s
+
+// Make sure that the LLVM attribute for XRay-annotated functions do show up.
+[[clang::xray_always_instrument]] void foo() {
+// CHECK: define void @_Z3foov() #0
+};
+
+[[clang::xray_never_instrument]] void bar() {
+// CHECK: define void @_Z3barv() #1
+};
+
+// CHECK: #0 = {{.*}}"function-instrument"="xray-always"
+// CHECK: #1 = {{.*}}"function-instrument"="xray-never"
Added: cfe/trunk/test/Sema/xray-always-instrument-attr.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/xray-always-instrument-attr.c?rev=275330&view=auto
==============================================================================
--- cfe/trunk/test/Sema/xray-always-instrument-attr.c (added)
+++ cfe/trunk/test/Sema/xray-always-instrument-attr.c Wed Jul 13 17:32:15 2016
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 %s -verify -fsyntax-only -std=c11
+void foo() __attribute__((xray_always_instrument));
+
+struct __attribute__((xray_always_instrument)) a { int x; }; // expected-warning {{'xray_always_instrument' attribute only applies to functions and methods}}
+
+void bar() __attribute__((xray_always_instrument("not-supported"))); // expected-error {{'xray_always_instrument' attribute takes no arguments}}
Added: cfe/trunk/test/Sema/xray-always-instrument-attr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/xray-always-instrument-attr.cpp?rev=275330&view=auto
==============================================================================
--- cfe/trunk/test/Sema/xray-always-instrument-attr.cpp (added)
+++ cfe/trunk/test/Sema/xray-always-instrument-attr.cpp Wed Jul 13 17:32:15 2016
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 %s -verify -fsyntax-only -std=c++11 -x c++
+void foo [[clang::xray_always_instrument]] ();
+
+struct [[clang::xray_always_instrument]] a { int x; }; // expected-warning {{'xray_always_instrument' attribute only applies to functions and methods}}
+
+class b {
+ void c [[clang::xray_always_instrument]] ();
+};
+
+void baz [[clang::xray_always_instrument("not-supported")]] (); // expected-error {{'xray_always_instrument' attribute takes no arguments}}
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