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Added Control Flow Protection Flag 

Cf-protection is a target independent flag that instructs the back-end to instrument control flow mechanisms like: Branch, Return, etc.
For example in X86 this flag will be used to instrument Indirect Branch Tracking instructions.

Differential Revision: https://reviews.llvm.org/D40478

Change-Id: I5126e766c0e6b84118cae0ee8a20fe78cc373dea
llvm-svn: 322063
This commit is contained in:
Oren Ben Simhon 2018-01-09 08:53:59 +00:00
parent 1c6308ecd5
commit 57cc1a5d77
12 changed files with 105 additions and 2 deletions
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2
clang/include/clang/Basic/DiagnosticCommonKinds.td
View File

@ -203,6 +203,8 @@ def err_target_unsupported_execute_only : Error<
"execute only is not supported for the %0 sub-architecture">;
def err_opt_not_valid_with_opt : Error<
"option '%0' cannot be specified with '%1'">;
def err_opt_not_valid_without_opt : Error<
"option '%0' cannot be specified without '%1'">;
// Source manager
def err_cannot_open_file : Error<"cannot open file '%0': %1">, DefaultFatal;

12
clang/include/clang/Basic/TargetInfo.h
View File

@ -1051,6 +1051,18 @@ public:
return false;
}
/// Check if the target supports CFProtection branch.
virtual bool
checkCFProtectionBranchSupported(DiagnosticsEngine &Diags) const {
return false;
}
/// Check if the target supports CFProtection branch.
virtual bool
checkCFProtectionReturnSupported(DiagnosticsEngine &Diags) const {
return false;
}
/// \brief Whether target allows to overalign ABI-specified preferred alignment
virtual bool allowsLargerPreferedTypeAlignment() const { return true; }

5
clang/include/clang/Driver/Options.td
View File

@ -1042,6 +1042,11 @@ def finstrument_functions_after_inlining : Flag<["-"], "finstrument-functions-af
HelpText<"Like -finstrument-functions, but insert the calls after inlining">;
def finstrument_function_entry_bare : Flag<["-"], "finstrument-function-entry-bare">, Group<f_Group>, Flags<[CC1Option]>,
HelpText<"Instrument function entry only, after inlining, without arguments to the instrumentation call">;
def fcf_protection_EQ : Joined<["-"], "fcf-protection=">, Flags<[CoreOption, CC1Option]>, Group<f_Group>,
HelpText<"Instrument control-flow architecture protection. Options: return, branch, full, none.">, Values<"return,branch,full,none">;
def fcf_protection : Flag<["-"], "fcf-protection">, Group<f_Group>, Flags<[CoreOption, CC1Option]>,
Alias<fcf_protection_EQ>, AliasArgs<["full"]>,
HelpText<"Enable cf-protection in 'full' mode">;
def fxray_instrument : Flag<["-"], "fxray-instrument">, Group<f_Group>,
Flags<[CC1Option]>,

5
clang/include/clang/Frontend/CodeGenOptions.def
View File

@ -80,7 +80,10 @@ CODEGENOPT(InstrumentFunctionsAfterInlining , 1, 0) ///< Set when
///< -finstrument-functions-after-inlining is enabled.
CODEGENOPT(InstrumentFunctionEntryBare , 1, 0) ///< Set when
///< -finstrument-function-entry-bare is enabled.
CODEGENOPT(CFProtectionReturn , 1, 0) ///< if -fcf-protection is
///< set to full or return.
CODEGENOPT(CFProtectionBranch , 1, 0) ///< if -fcf-protection is
///< set to full or branch.
CODEGENOPT(XRayInstrumentFunctions , 1, 0) ///< Set when -fxray-instrument is
///< enabled.
CODEGENOPT(StackSizeSection , 1, 0) ///< Set when -fstack-size-section is enabled.

20
clang/lib/Basic/Targets/X86.cpp
View File

@ -101,6 +101,26 @@ bool X86TargetInfo::setFPMath(StringRef Name) {
return false;
}
bool X86TargetInfo::checkCFProtectionReturnSupported(
DiagnosticsEngine &Diags) const {
if (HasSHSTK)
return true;
Diags.Report(diag::err_opt_not_valid_without_opt) << "cf-protection=return"
<< "-mshstk";
return false;
}
bool X86TargetInfo::checkCFProtectionBranchSupported(
DiagnosticsEngine &Diags) const {
if (HasIBT)
return true;
Diags.Report(diag::err_opt_not_valid_without_opt) << "cf-protection=branch"
<< "-mibt";
return false;
}
bool X86TargetInfo::initFeatureMap(
llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
const std::vector<std::string> &FeaturesVec) const {

6
clang/lib/Basic/Targets/X86.h
View File

@ -158,6 +158,12 @@ public:
bool validateInputSize(StringRef Constraint, unsigned Size) const override;
virtual bool
checkCFProtectionReturnSupported(DiagnosticsEngine &Diags) const override;
virtual bool
checkCFProtectionBranchSupported(DiagnosticsEngine &Diags) const override;
virtual bool validateOperandSize(StringRef Constraint, unsigned Size) const;
std::string convertConstraint(const char *&Constraint) const override;

3
clang/lib/CodeGen/CodeGenFunction.cpp
View File

@ -887,7 +887,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
}
// Apply xray attributes to the function (as a string, for now)
if (D && ShouldXRayInstrumentFunction()) {
bool InstrumentXray = ShouldXRayInstrumentFunction();
if (D && InstrumentXray) {
if (const auto *XRayAttr = D->getAttr<XRayInstrumentAttr>()) {
if (XRayAttr->alwaysXRayInstrument())
Fn->addFnAttr("function-instrument", "xray-always");

14
clang/lib/CodeGen/CodeGenModule.cpp
View File

@ -502,6 +502,20 @@ void CodeGenModule::Release() {
getModule().addModuleFlag(llvm::Module::Override, "Cross-DSO CFI", 1);
}
if (CodeGenOpts.CFProtectionReturn &&
Target.checkCFProtectionReturnSupported(getDiags())) {
// Indicate that we want to instrument return control flow protection.
getModule().addModuleFlag(llvm::Module::Override, "cf-protection-return",
1);
}
if (CodeGenOpts.CFProtectionBranch &&
Target.checkCFProtectionBranchSupported(getDiags())) {
// Indicate that we want to instrument branch control flow protection.
getModule().addModuleFlag(llvm::Module::Override, "cf-protection-branch",
1);
}
if (LangOpts.CUDAIsDevice && getTriple().isNVPTX()) {
// Indicate whether __nvvm_reflect should be configured to flush denormal
// floating point values to 0. (This corresponds to its "__CUDA_FTZ"

5
clang/lib/Driver/ToolChains/Clang.cpp
View File

@ -4008,6 +4008,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
// Forward -cl options to -cc1
RenderOpenCLOptions(Args, CmdArgs);
if (Arg *A = Args.getLastArg(options::OPT_fcf_protection_EQ)) {
CmdArgs.push_back(
Args.MakeArgString(Twine("-fcf-protection=") + A->getValue()));
}
// Forward -f options with positive and negative forms; we translate
// these by hand.
if (Arg *A = getLastProfileSampleUseArg(Args)) {

15
clang/lib/Frontend/CompilerInvocation.cpp
View File

@ -798,6 +798,21 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
Opts.CallFEntry = Args.hasArg(OPT_mfentry);
Opts.EmitOpenCLArgMetadata = Args.hasArg(OPT_cl_kernel_arg_info);
if (const Arg *A = Args.getLastArg(OPT_fcf_protection_EQ)) {
StringRef Name = A->getValue();
if (Name == "full") {
Opts.CFProtectionReturn = 1;
Opts.CFProtectionBranch = 1;
} else if (Name == "return")
Opts.CFProtectionReturn = 1;
else if (Name == "branch")
Opts.CFProtectionBranch = 1;
else if (Name != "none") {
Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;
Success = false;
}
}
if (const Arg *A = Args.getLastArg(OPT_compress_debug_sections,
OPT_compress_debug_sections_EQ)) {
if (A->getOption().getID() == OPT_compress_debug_sections) {

6
clang/test/CodeGen/x86-cf-protection.c Normal file
View File

@ -0,0 +1,6 @@
// RUN: not %clang_cc1 -fsyntax-only -S -emit-llvm -triple i386-unknown-unknown -fcf-protection=return %s 2>&1 | FileCheck %s --check-prefix=RETURN
// RUN: not %clang_cc1 -fsyntax-only -S -emit-llvm -triple i386-unknown-unknown -fcf-protection=branch %s 2>&1 | FileCheck %s --check-prefix=BRANCH
// RETURN: error: option 'cf-protection=return' cannot be specified without '-mshstk'
// BRANCH: error: option 'cf-protection=branch' cannot be specified without '-mibt'
void foo() {}

14
clang/test/Driver/clang_f_opts.c
View File

@ -503,3 +503,17 @@
// CHECK-WINDOWS-ISO10646: "-fwchar-type=int"
// CHECK-WINDOWS-ISO10646: "-fsigned-wchar"
// RUN: %clang -### -S -fcf-protection %s 2>&1 | FileCheck -check-prefix=CHECK-CF-PROTECTION-FULL %s
// RUN: %clang -### -S %s 2>&1 | FileCheck -check-prefix=CHECK-NO-CF-PROTECTION-FULL %s
// RUN: %clang -### -S -fcf-protection=full %s 2>&1 | FileCheck -check-prefix=CHECK-CF-PROTECTION-FULL %s
// RUN: %clang -### -S %s 2>&1 | FileCheck -check-prefix=CHECK-NO-CF-PROTECTION-FULL %s
// CHECK-CF-PROTECTION-FULL: -fcf-protection=full
// CHECK-NO-CF-PROTECTION-FULL-NOT: -fcf-protection=full
// RUN: %clang -### -S -fcf-protection=return %s 2>&1 | FileCheck -check-prefix=CHECK-CF-PROTECTION-RETURN %s
// RUN: %clang -### -S %s 2>&1 | FileCheck -check-prefix=CHECK-NO-CF-PROTECTION-RETURN %s
// CHECK-CF-PROTECTION-RETURN: -fcf-protection=return
// CHECK-NO-CF-PROTECTION-RETURN-NOT: -fcf-protection=return
// RUN: %clang -### -S -fcf-protection=branch %s 2>&1 | FileCheck -check-prefix=CHECK-CF-PROTECTION-BRANCH %s
// RUN: %clang -### -S %s 2>&1 | FileCheck -check-prefix=CHECK-NO-CF-PROTECTION-BRANCH %s
// CHECK-CF-PROTECTION-BRANCH: -fcf-protection=branch
// CHECK-NO-CF-PROTECTION-BRANCH-NOT: -fcf-protection=branch