From 05cf44346346c0308396cf59b2c7228b2b3eff30 Mon Sep 17 00:00:00 2001 From: Dean Michael Berris Date: Fri, 14 Sep 2018 01:59:12 +0000 Subject: [PATCH] [XRay][clang] Emit "never-instrument" attribute Summary: Before this change, we only emit the XRay attributes in LLVM IR when the -fxray-instrument flag is provided. This may cause issues with thinlto when the final binary is being built/linked with -fxray-instrument, and the constitutent LLVM IR gets re-lowered with xray instrumentation. With this change, we can honour the "never-instrument "attributes provided in the source code and preserve those in the IR. This way, even in thinlto builds, we retain the attributes which say whether functions should never be XRay instrumented. This change addresses llvm.org/PR38922. Reviewers: mboerger, eizan Subscribers: mehdi_amini, dexonsmith, cfe-commits, llvm-commits Differential Revision: https://reviews.llvm.org/D52015 llvm-svn: 342200 --- clang/lib/CodeGen/CodeGenFunction.cpp | 24 +++++++++--------- clang/lib/CodeGen/CodeGenModule.cpp | 3 --- .../CodeGen/xray-attributes-noxray-supported.cpp | 29 ++++++++++++++++++++++ clang/test/CodeGen/xray-attributes-supported.cpp | 21 ++++++++++------ .../TestCases/Posix/clang-no-xray-instrument.cc | 11 ++++++++ 5 files changed, 66 insertions(+), 22 deletions(-) create mode 100644 clang/test/CodeGen/xray-attributes-noxray-supported.cpp create mode 100644 compiler-rt/test/xray/TestCases/Posix/clang-no-xray-instrument.cc diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp index d142755..77f978f 100644 --- a/clang/lib/CodeGen/CodeGenFunction.cpp +++ b/clang/lib/CodeGen/CodeGenFunction.cpp @@ -901,21 +901,21 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, } // Apply xray attributes to the function (as a string, for now) - bool InstrumentXray = ShouldXRayInstrumentFunction() && - CGM.getCodeGenOpts().XRayInstrumentationBundle.has( - XRayInstrKind::Function); - if (D && InstrumentXray) { + if (D) { if (const auto *XRayAttr = D->getAttr()) { - if (XRayAttr->alwaysXRayInstrument()) - Fn->addFnAttr("function-instrument", "xray-always"); - if (XRayAttr->neverXRayInstrument()) - Fn->addFnAttr("function-instrument", "xray-never"); - if (const auto *LogArgs = D->getAttr()) { - Fn->addFnAttr("xray-log-args", - llvm::utostr(LogArgs->getArgumentCount())); + if (CGM.getCodeGenOpts().XRayInstrumentationBundle.has( + XRayInstrKind::Function)) { + if (XRayAttr->alwaysXRayInstrument() && ShouldXRayInstrumentFunction()) + Fn->addFnAttr("function-instrument", "xray-always"); + if (XRayAttr->neverXRayInstrument()) + Fn->addFnAttr("function-instrument", "xray-never"); + if (const auto *LogArgs = D->getAttr()) + if (ShouldXRayInstrumentFunction()) + Fn->addFnAttr("xray-log-args", + llvm::utostr(LogArgs->getArgumentCount())); } } else { - if (!CGM.imbueXRayAttrs(Fn, Loc)) + if (ShouldXRayInstrumentFunction() && !CGM.imbueXRayAttrs(Fn, Loc)) Fn->addFnAttr( "xray-instruction-threshold", llvm::itostr(CGM.getCodeGenOpts().XRayInstructionThreshold)); diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index 7df2ea7..49c926db5 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -1967,9 +1967,6 @@ bool CodeGenModule::isInSanitizerBlacklist(llvm::GlobalVariable *GV, bool CodeGenModule::imbueXRayAttrs(llvm::Function *Fn, SourceLocation Loc, StringRef Category) const { - if (!LangOpts.XRayInstrument) - return false; - const auto &XRayFilter = getContext().getXRayFilter(); using ImbueAttr = XRayFunctionFilter::ImbueAttribute; auto Attr = ImbueAttr::NONE; diff --git a/clang/test/CodeGen/xray-attributes-noxray-supported.cpp b/clang/test/CodeGen/xray-attributes-noxray-supported.cpp new file mode 100644 index 0000000..f9c8a2e --- /dev/null +++ b/clang/test/CodeGen/xray-attributes-noxray-supported.cpp @@ -0,0 +1,29 @@ +// We want to ensure that the "never instrument" attributes show up even if we +// explicitly turn off XRay instrumentation. +// +// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple x86_64-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple arm-unknown-linux-gnu -target-abi apcs-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple mips-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple mipsel-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple mips64-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple mips64el-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple powerpc64le-unknown-linux-gnu | FileCheck %s + +[[clang::xray_always_instrument]] void foo() { +// CHECK: define void @_Z3foov() #0 +} + +[[clang::xray_never_instrument]] void bar() { +// CHECK: define void @_Z3barv() #1 +} + +// CHECK-NOT: #0 = {{.*}}"function-instrument"="xray-always" +// CHECK: #1 = {{.*}}"function-instrument"="xray-never" + diff --git a/clang/test/CodeGen/xray-attributes-supported.cpp b/clang/test/CodeGen/xray-attributes-supported.cpp index 21a5dde..51ee472 100644 --- a/clang/test/CodeGen/xray-attributes-supported.cpp +++ b/clang/test/CodeGen/xray-attributes-supported.cpp @@ -1,10 +1,17 @@ -// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - -triple x86_64-unknown-linux-gnu | FileCheck %s -// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - -triple arm-unknown-linux-gnu -target-abi apcs-gnu | FileCheck %s -// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - -triple mips-unknown-linux-gnu | FileCheck %s -// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - -triple mipsel-unknown-linux-gnu | FileCheck %s -// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - -triple mips64-unknown-linux-gnu | FileCheck %s -// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - -triple mips64el-unknown-linux-gnu | FileCheck %s -// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - -triple powerpc64le-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple x86_64-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple arm-unknown-linux-gnu -target-abi apcs-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple mips-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple mipsel-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple mips64-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple mips64el-unknown-linux-gnu | FileCheck %s +// RUN: %clang_cc1 %s -fxray-instrument -std=c++11 -x c++ -emit-llvm -o - \ +// RUN: -triple powerpc64le-unknown-linux-gnu | FileCheck %s // Make sure that the LLVM attribute for XRay-annotated functions do show up. [[clang::xray_always_instrument]] void foo() { diff --git a/compiler-rt/test/xray/TestCases/Posix/clang-no-xray-instrument.cc b/compiler-rt/test/xray/TestCases/Posix/clang-no-xray-instrument.cc new file mode 100644 index 0000000..c2444b1 --- /dev/null +++ b/compiler-rt/test/xray/TestCases/Posix/clang-no-xray-instrument.cc @@ -0,0 +1,11 @@ +// Test that we cannot actually find XRay instrumentation when we build with +// -fno-xray-instrument but have code that's marked as 'xray_always_instrument'. +// +// RUN: %clangxx -fno-xray-instrument -c %s -o %t.o +// RUN: not %llvm_xray extract -symbolize %t.o 2>&1 | FileCheck %s +// REQUIRES: x86_64-target-arch +// REQUIRES: built-in-llvm-tree + +// CHECK: llvm-xray: Cannot extract instrumentation map +// CHECK-NOT: {{.*always_instrumented.*}} +[[clang::xray_always_instrument]] int always_instrumented() { return 42; } -- 2.7.4