r319388 - [XRay][clang] Introduce -fxray-always-emit-customevents
Dean Michael Berris via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 29 16:04:54 PST 2017
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)
+}
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