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Revert "[Clang][ARM][AArch64] Alway emit protection attributes for functions." #98284

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Jul 10, 2024
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Revert "[Clang][ARM][AArch64] Alway emit protection attributes for functions." #98284

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44 changes: 3 additions & 41 deletions clang/include/clang/Basic/TargetInfo.h
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Original file line number Diff line number Diff line change
Expand Up @@ -32,9 +32,7 @@
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Frontend/OpenMP/OMPGridValues.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/VersionTuple.h"
Expand Down Expand Up @@ -1402,15 +1400,15 @@ class TargetInfo : public TransferrableTargetInfo,
return true;
}

class BranchProtectionInfo {
public:
struct BranchProtectionInfo {
LangOptions::SignReturnAddressScopeKind SignReturnAddr;
LangOptions::SignReturnAddressKeyKind SignKey;
bool BranchTargetEnforcement;
bool BranchProtectionPAuthLR;
bool GuardedControlStack;

protected:
BranchProtectionInfo() = default;

const char *getSignReturnAddrStr() const {
switch (SignReturnAddr) {
case LangOptions::SignReturnAddressScopeKind::None:
Expand All @@ -1432,42 +1430,6 @@ class TargetInfo : public TransferrableTargetInfo,
}
llvm_unreachable("Unexpected SignReturnAddressKeyKind");
}

public:
BranchProtectionInfo() = default;
BranchProtectionInfo(const LangOptions &LangOpts) {
SignReturnAddr =
LangOpts.hasSignReturnAddress()
? (LangOpts.isSignReturnAddressScopeAll()
? LangOptions::SignReturnAddressScopeKind::All
: LangOptions::SignReturnAddressScopeKind::NonLeaf)
: LangOptions::SignReturnAddressScopeKind::None;
SignKey = LangOpts.isSignReturnAddressWithAKey()
? LangOptions::SignReturnAddressKeyKind::AKey
: LangOptions::SignReturnAddressKeyKind::BKey;
BranchTargetEnforcement = LangOpts.BranchTargetEnforcement;
BranchProtectionPAuthLR = LangOpts.BranchProtectionPAuthLR;
GuardedControlStack = LangOpts.GuardedControlStack;
}

void setFnAttributes(llvm::Function &F) {
llvm::AttrBuilder FuncAttrs(F.getContext());
setFnAttributes(FuncAttrs);
F.addFnAttrs(FuncAttrs);
}

void setFnAttributes(llvm::AttrBuilder &FuncAttrs) {
if (SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
FuncAttrs.addAttribute("sign-return-address", getSignReturnAddrStr());
FuncAttrs.addAttribute("sign-return-address-key", getSignKeyStr());
}
if (BranchTargetEnforcement)
FuncAttrs.addAttribute("branch-target-enforcement");
if (BranchProtectionPAuthLR)
FuncAttrs.addAttribute("branch-protection-pauth-lr");
if (GuardedControlStack)
FuncAttrs.addAttribute("guarded-control-stack");
}
};

/// Determine if the Architecture in this TargetInfo supports branch
Expand Down
43 changes: 30 additions & 13 deletions clang/lib/CodeGen/Targets/AArch64.cpp
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Expand Up @@ -120,20 +120,37 @@ class AArch64TargetCodeGenInfo : public TargetCodeGenInfo {
if (!FD)
return;

TargetInfo::BranchProtectionInfo BPI(CGM.getLangOpts());

if (const auto *TA = FD->getAttr<TargetAttr>()) {
ParsedTargetAttr Attr =
CGM.getTarget().parseTargetAttr(TA->getFeaturesStr());
if (!Attr.BranchProtection.empty()) {
StringRef Error;
(void)CGM.getTarget().validateBranchProtection(Attr.BranchProtection,
Attr.CPU, BPI, Error);
assert(Error.empty());
}
}
const auto *TA = FD->getAttr<TargetAttr>();
if (TA == nullptr)
return;

ParsedTargetAttr Attr =
CGM.getTarget().parseTargetAttr(TA->getFeaturesStr());
if (Attr.BranchProtection.empty())
return;

TargetInfo::BranchProtectionInfo BPI;
StringRef Error;
(void)CGM.getTarget().validateBranchProtection(Attr.BranchProtection,
Attr.CPU, BPI, Error);
assert(Error.empty());

auto *Fn = cast<llvm::Function>(GV);
BPI.setFnAttributes(*Fn);
Fn->addFnAttr("sign-return-address", BPI.getSignReturnAddrStr());

if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
Fn->addFnAttr("sign-return-address-key",
BPI.SignKey == LangOptions::SignReturnAddressKeyKind::AKey
? "a_key"
: "b_key");
}

Fn->addFnAttr("branch-target-enforcement",
BPI.BranchTargetEnforcement ? "true" : "false");
Fn->addFnAttr("branch-protection-pauth-lr",
BPI.BranchProtectionPAuthLR ? "true" : "false");
Fn->addFnAttr("guarded-control-stack",
BPI.GuardedControlStack ? "true" : "false");
}

bool isScalarizableAsmOperand(CodeGen::CodeGenFunction &CGF,
Expand Down
8 changes: 3 additions & 5 deletions clang/lib/CodeGen/Targets/ARM.cpp
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Expand Up @@ -152,7 +152,9 @@ class ARMTargetCodeGenInfo : public TargetCodeGenInfo {
diag::warn_target_unsupported_branch_protection_attribute)
<< Arch;
} else {
BPI.setFnAttributes(*Fn);
Fn->addFnAttr("sign-return-address", BPI.getSignReturnAddrStr());
Fn->addFnAttr("branch-target-enforcement",
BPI.BranchTargetEnforcement ? "true" : "false");
}
} else if (CGM.getLangOpts().BranchTargetEnforcement ||
CGM.getLangOpts().hasSignReturnAddress()) {
Expand All @@ -165,10 +167,6 @@ class ARMTargetCodeGenInfo : public TargetCodeGenInfo {
diag::warn_target_unsupported_branch_protection_attribute)
<< Attr.CPU;
}
} else if (CGM.getTarget().isBranchProtectionSupportedArch(
CGM.getTarget().getTargetOpts().CPU)) {
TargetInfo::BranchProtectionInfo BPI(CGM.getLangOpts());
BPI.setFnAttributes(*Fn);
}

const ARMInterruptAttr *Attr = FD->getAttr<ARMInterruptAttr>();
Expand Down
26 changes: 13 additions & 13 deletions clang/test/CodeGen/aarch64-branch-protection-attr.c
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Expand Up @@ -67,29 +67,29 @@ __attribute__ ((target("branch-protection=gcs")))
void gcs() {}
// CHECK: define{{.*}} void @gcs() #[[#GCS:]]

// CHECK-DAG: attributes #[[#NONE]] = { {{.*}}
// CHECK-DAG: attributes #[[#NONE]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="none"

// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement" "guarded-control-stack" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement"="true" "guarded-control-stack"="true" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"

// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"
// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}} "sign-return-address"="none"

// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"

// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "sign-return-address"="all" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"

// CHECK-DAG: attributes #[[#PACBKEY]] = { {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
// CHECK-DAG: attributes #[[#PACBKEY]] = { {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="b_key"

// CHECK-DAG: attributes #[[#PACBKEYLEAF]] = { {{.*}} "sign-return-address"="all" "sign-return-address-key"="b_key"
// CHECK-DAG: attributes #[[#PACBKEYLEAF]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="b_key"

// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}} "branch-target-enforcement" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}}"branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}} "sign-return-address"="all" "sign-return-address-key"="a_key"


// CHECK-DAG: attributes #[[#PAUTHLR]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#PAUTHLR]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"

// CHECK-DAG: attributes #[[#PAUTHLR_BKEY]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
// CHECK-DAG: attributes #[[#PAUTHLR_BKEY]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="b_key"

// CHECK-DAG: attributes #[[#PAUTHLR_LEAF]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#PAUTHLR_LEAF]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"

// CHECK-DAG: attributes #[[#PAUTHLR_BTI]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"branch-target-enforcement" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#PAUTHLR_BTI]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"

// CHECK-DAG: attributes #[[#GCS]] = { {{.*}} "guarded-control-stack"
// CHECK-DAG: attributes #[[#GCS]] = { {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="true" {{.*}} "sign-return-address"="none"
12 changes: 3 additions & 9 deletions clang/test/CodeGen/aarch64-sign-return-address.c
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Expand Up @@ -13,15 +13,9 @@

// CHECK-LABEL: @foo() #[[#ATTR:]]

// NONE-NOT: attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
// NONE-NOT: attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"
// NONE-NOT: attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"

// ALL: attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
// PART: attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"="a_key"
// B-KEY: attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"="b_key"
// BTE: attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"

// CHECK-NOT: attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
// CHECK-NOT: attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"
// CHECK-NOT: attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"

// Check module attributes

Expand Down
12 changes: 6 additions & 6 deletions clang/test/CodeGen/arm-branch-protection-attr-1.c
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Expand Up @@ -29,14 +29,14 @@ __attribute__((target("branch-protection=pac-ret+leaf"))) void leaf() {}
__attribute__((target("branch-protection=pac-ret+leaf+bti"))) void btileaf() {}
// CHECK: define{{.*}} void @btileaf() #[[#BTIPACLEAF:]]

// CHECK-DAG: attributes #[[#NONE]] = { {{.*}}
// CHECK-DAG: attributes #[[#NONE]] = { {{.*}} "branch-target-enforcement"="false" {{.*}} "sign-return-address"="none"

// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement" {{.*}} "sign-return-address"="non-leaf"
// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement"="true" {{.*}} "sign-return-address"="non-leaf"

// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"
// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"="true" {{.*}} "sign-return-address"="none"

// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "sign-return-address"="non-leaf"
// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "branch-target-enforcement"="false" {{.*}} "sign-return-address"="non-leaf"

// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "sign-return-address"="all"
// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "branch-target-enforcement"="false" {{.*}}"sign-return-address"="all"

// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}} "branch-target-enforcement" {{.*}} "sign-return-address"="all"
// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}}"branch-target-enforcement"="true" {{.*}} "sign-return-address"="all"
13 changes: 4 additions & 9 deletions clang/test/CodeGen/arm-branch-protection-attr-2.c
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Expand Up @@ -5,18 +5,13 @@
// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -S -emit-llvm -o - -mbranch-protection=pac-ret+b-key %s | FileCheck %s --check-prefix=CHECK --check-prefix=PART
// RUN: %clang -target arm-arm-none-eabi -march=armv8.1-m.main -S -emit-llvm -o - -mbranch-protection=bti %s | FileCheck %s --check-prefix=CHECK --check-prefix=BTE

// Check there are branch protection function attributes
// Check there are no branch protection function attributes

// CHECK-LABEL: @foo() #[[#ATTR:]]

// NONE-NOT: attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
// NONE-NOT: attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"
// NONE-NOT: attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"

// ALL: attributes #[[#ATTR]] = { {{.*}} "sign-return-address"="all"
// PART: attributes #[[#ATTR]] = { {{.*}} "sign-return-address"="non-leaf"
// BTE: attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"

// CHECK-NOT: attributes #[[#ATTR]] = { {{.*}} "sign-return-address"
// CHECK-NOT: attributes #[[#ATTR]] = { {{.*}} "sign-return-address-key"
// CHECK-NOT: attributes #[[#ATTR]] = { {{.*}} "branch-target-enforcement"

// Check module attributes

Expand Down
24 changes: 0 additions & 24 deletions clang/test/Frontend/arm-branch-protection-lto.c
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This file was deleted.

12 changes: 11 additions & 1 deletion llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
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Expand Up @@ -12012,7 +12012,17 @@ void SelectionDAGBuilder::lowerWorkItem(SwitchWorkListItem W, Value *Cond,
// table branch.
if (FallthroughUnreachable) {
Function &CurFunc = CurMF->getFunction();
if (!CurFunc.hasFnAttribute("branch-target-enforcement"))
bool HasBranchTargetEnforcement = false;
if (CurFunc.hasFnAttribute("branch-target-enforcement")) {
HasBranchTargetEnforcement =
CurFunc.getFnAttribute("branch-target-enforcement")
.getValueAsBool();
} else {
HasBranchTargetEnforcement =
CurMF->getMMI().getModule()->getModuleFlag(
"branch-target-enforcement");
}
if (!HasBranchTargetEnforcement)
JTH->FallthroughUnreachable = true;
}

Expand Down
20 changes: 1 addition & 19 deletions llvm/lib/IR/Verifier.cpp
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Expand Up @@ -2348,33 +2348,15 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
if (S != "a_key" && S != "b_key")
CheckFailed("invalid value for 'sign-return-address-key' attribute: " + S,
V);
if (auto AA = Attrs.getFnAttr("sign-return-address"); !AA.isValid()) {
CheckFailed(
"'sign-return-address-key' present without `sign-return-address`");
}
}

if (auto A = Attrs.getFnAttr("branch-target-enforcement"); A.isValid()) {
StringRef S = A.getValueAsString();
if (S != "" && S != "true" && S != "false")
if (S != "true" && S != "false")
CheckFailed(
"invalid value for 'branch-target-enforcement' attribute: " + S, V);
}

if (auto A = Attrs.getFnAttr("branch-protection-pauth-lr"); A.isValid()) {
StringRef S = A.getValueAsString();
if (S != "" && S != "true" && S != "false")
CheckFailed(
"invalid value for 'branch-protection-pauth-lr' attribute: " + S, V);
}

if (auto A = Attrs.getFnAttr("guarded-control-stack"); A.isValid()) {
StringRef S = A.getValueAsString();
if (S != "" && S != "true" && S != "false")
CheckFailed("invalid value for 'guarded-control-stack' attribute: " + S,
V);
}

if (auto A = Attrs.getFnAttr("vector-function-abi-variant"); A.isValid()) {
StringRef S = A.getValueAsString();
const std::optional<VFInfo> Info = VFABI::tryDemangleForVFABI(S, FT);
Expand Down
6 changes: 3 additions & 3 deletions llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
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Expand Up @@ -272,17 +272,17 @@ void AArch64AsmPrinter::emitStartOfAsmFile(Module &M) {
unsigned Flags = 0;
if (const auto *BTE = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("branch-target-enforcement")))
if (!BTE->isZero())
if (BTE->getZExtValue())
Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI;

if (const auto *GCS = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("guarded-control-stack")))
if (!GCS->isZero())
if (GCS->getZExtValue())
Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_GCS;

if (const auto *Sign = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("sign-return-address")))
if (!Sign->isZero())
if (Sign->getZExtValue())
Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_PAC;

uint64_t PAuthABIPlatform = -1;
Expand Down
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