[AArch64][PAC] Emit a fatal error when ptrauth target feature is missing

llvm/lib/Target/AArch64/AArch64ExpandHardenedPseudos.cpp

@@ -171,6 +171,9 @@ bool AArch64ExpandHardenedPseudos::expandPtrAuthPseudo(MachineInstr &MI) {
   if (MI.getOpcode() == AArch64::LOADauthptrgot) {
     LLVM_DEBUG(dbgs() << "Expanding: " << MI << "\n");
 
+    if (!STI.hasPAuth())
+      report_fatal_error("pac instructions require ptrauth target feature");
+
     const TargetMachine &TM = MF.getTarget();
     MachineModuleInfo &MMI = MF.getMMI();
 
@@ -223,6 +226,9 @@ bool AArch64ExpandHardenedPseudos::expandPtrAuthPseudo(MachineInstr &MI) {
 
   LLVM_DEBUG(dbgs() << "Expanding: " << MI << "\n");
 
+  if (!STI.hasPAuth())
+    report_fatal_error("pac instructions require ptrauth target feature");
+
   const bool IsGOTLoad = MI.getOpcode() == AArch64::LOADgotPAC;
   MachineOperand GAOp = MI.getOperand(0);
   auto Key = (AArch64PACKey::ID)MI.getOperand(1).getImm();
@@ -332,6 +338,11 @@ bool AArch64ExpandHardenedPseudos::expandAuthLoad(MachineInstr &MI) {
 
   LLVM_DEBUG(dbgs() << "Expanding: " << MI << "\n");
 
+  // LDRA and LDRApre preudos are emitted in AArch64DAGToDAGISel::tryAuthLoad
+  // and AArch64InstructionSelector::selectAuthLoad with prior checks against
+  // ptrauth subtarget feature
+  assert(STI.hasPAuth());
+
   bool IsPre = MI.getOpcode() == AArch64::LDRApre;
 
   MachineOperand DstOp = MI.getOperand(0);

llvm/lib/Target/AArch64/AArch64FrameLowering.cpp

@@ -1511,7 +1511,9 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
   // If we're saving LR, sign it first.
   if (shouldAuthenticateLR(MF)) {
     if (LLVM_UNLIKELY(!Subtarget.hasPAuth()))
-      report_fatal_error("arm64e LR authentication requires ptrauth");
+      report_fatal_error(
+          StringRef(Subtarget.isTargetMachO() ? "arm64e" : "aarch64") +
+          " LR authentication requires ptrauth");
     for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo()) {
       if (Info.getReg() != AArch64::LR)
         continue;
@@ -2051,7 +2053,9 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
   auto InsertAuthLROnExit = make_scope_exit([&]() {
     if (shouldAuthenticateLR(MF)) {
       if (LLVM_UNLIKELY(!Subtarget.hasPAuth()))
-        report_fatal_error("arm64e LR authentication requires ptrauth");
+        report_fatal_error(
+            StringRef(Subtarget.isTargetMachO() ? "arm64e" : "aarch64") +
+            " LR authentication requires ptrauth");
       for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo()) {
         if (Info.getReg() != AArch64::LR)
           continue;

llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp

@@ -1723,6 +1723,9 @@ bool AArch64DAGToDAGISel::tryAuthLoad(SDNode *N) {
         return false;
   }
 
+  if (!Subtarget->hasPAuth())
+    report_fatal_error("pac instructions require ptrauth target feature");
+
   // We have 2 main isel alternatives:
   // - LDRAA/LDRAB, writeback or indexed.  Zero disc, small offsets, D key.
   // - LDRA/LDRApre.  Pointer needs to be in X16.

llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp

@@ -2856,6 +2856,9 @@ bool AArch64InstructionSelector::select(MachineInstr &I) {
 
   case AArch64::G_LDRA:
   case AArch64::G_LDRApre:
+    // TODO: implement a test case for this error
+    if (!STI.hasPAuth())
+      report_fatal_error("pac instructions require ptrauth target feature");
     return selectAuthLoad(I, MRI);
 
   case TargetOpcode::G_ZEXTLOAD:

llvm/test/CodeGen/AArch64/GlobalISel/ptrauth-lowering-err-debug.ll

@@ -0,0 +1,60 @@
+; REQUIRES: asserts
+; RUN: split-file %s %t && cd %t
+
+;--- MOVaddrPAC.ll
+
+; RUN: not --crash llc -debug-only=aarch64-expand-hardened-pseudos -mtriple aarch64-elf MOVaddrPAC.ll 2>&1 | \
+; RUN:   FileCheck MOVaddrPAC.ll
+
+; CHECK:      Expanding: MOVaddrPAC @foo
+; CHECK-NEXT: {{^$}}
+; CHECK-NEXT: LLVM ERROR: pac instructions require ptrauth target feature
+
+@foo.ptrauth = private constant { ptr, i32, i64, i64 } { ptr @foo, i32 0, i64 0, i64 0 }, section "llvm.ptrauth", align 8
+
+define ptr @bar() #0 {
+  ret ptr @foo.ptrauth
+}
+
+define private void @foo() {
+  ret void
+}
+
+attributes #0 = { "ptrauth-calls" "target-cpu"="generic" }
+
+;--- LOADgotPAC.ll
+
+; RUN: not --crash llc -debug-only=aarch64-expand-hardened-pseudos -mtriple aarch64-elf LOADgotPAC.ll 2>&1 | \
+; RUN:   FileCheck LOADgotPAC.ll
+
+; CHECK:      Expanding: LOADgotPAC @foo
+; CHECK-NEXT: {{^$}}
+; CHECK-NEXT: LLVM ERROR: pac instructions require ptrauth target feature
+
+@foo.ptrauth = private constant { ptr, i32, i64, i64 } { ptr @foo, i32 0, i64 0, i64 0 }, section "llvm.ptrauth", align 8
+
+define ptr @bar() #0 {
+  ret ptr @foo.ptrauth
+}
+
+declare void @foo()
+
+attributes #0 = { "ptrauth-calls" "target-cpu"="generic" }
+
+;--- LOADauthptrgot.ll
+
+; RUN: not --crash llc -debug-only=aarch64-expand-hardened-pseudos -mtriple aarch64-elf LOADauthptrgot.ll 2>&1 | \
+; RUN:   FileCheck LOADauthptrgot.ll
+
+; CHECK:      Expanding: {{.*}}LOADauthptrgot @g_weak
+; CHECK-NEXT: {{^$}}
+; CHECK-NEXT: LLVM ERROR: pac instructions require ptrauth target feature
+
+define ptr @foo() #0 {
+  ret ptr @g_weak.ptrauth
+}
+
+@g_weak = extern_weak global i32
+@g_weak.ptrauth = private constant { ptr, i32, i64, i64 } { ptr @g_weak, i32 0, i64 0, i64 0 }, section "llvm.ptrauth"
+
+attributes #0 = { "ptrauth-calls" "target-cpu"="generic" }

llvm/test/CodeGen/AArch64/GlobalISel/ptrauth-lowering-err.ll

@@ -0,0 +1,102 @@
+; RUN: split-file %s %t && cd %t
+
+;--- MOVaddrPAC.ll
+
+; RUN: not --crash llc -mtriple aarch64-elf MOVaddrPAC.ll 2>&1 | \
+; RUN:   FileCheck MOVaddrPAC.ll
+
+; CHECK: LLVM ERROR: pac instructions require ptrauth target feature
+
+@foo.ptrauth = private constant { ptr, i32, i64, i64 } { ptr @foo, i32 0, i64 0, i64 0 }, section "llvm.ptrauth", align 8
+
+define ptr @bar() #0 {
+  ret ptr @foo.ptrauth
+}
+
+define private void @foo() {
+  ret void
+}
+
+attributes #0 = { "ptrauth-calls" "target-cpu"="generic" }
+
+;--- LOADgotPAC.ll
+
+; RUN: not --crash llc -mtriple aarch64-elf LOADgotPAC.ll 2>&1 | \
+; RUN:   FileCheck LOADgotPAC.ll
+
+; CHECK: LLVM ERROR: pac instructions require ptrauth target feature
+
+@foo.ptrauth = private constant { ptr, i32, i64, i64 } { ptr @foo, i32 0, i64 0, i64 0 }, section "llvm.ptrauth", align 8
+
+define ptr @bar() #0 {
+  ret ptr @foo.ptrauth
+}
+
+declare void @foo()
+
+attributes #0 = { "ptrauth-calls" "target-cpu"="generic" }
+
+;--- LOADauthptrgot.ll
+
+; RUN: not --crash llc -mtriple aarch64-elf LOADauthptrgot.ll 2>&1 | \
+; RUN:   FileCheck LOADauthptrgot.ll
+
+; CHECK: LLVM ERROR: pac instructions require ptrauth target feature
+
+define ptr @foo() #0 {
+  ret ptr @g_weak.ptrauth
+}
+
+@g_weak = extern_weak global i32
+@g_weak.ptrauth = private constant { ptr, i32, i64, i64 } { ptr @g_weak, i32 0, i64 0, i64 0 }, section "llvm.ptrauth"
+
+attributes #0 = { "ptrauth-calls" "target-cpu"="generic" }
+
+;--- ptrauth-returns.ll
+
+; RUN: not --crash llc -mtriple aarch64-elf ptrauth-returns.ll 2>&1 | \
+; RUN:   FileCheck ptrauth-returns.ll
+
+; CHECK: LLVM ERROR: aarch64 LR authentication requires ptrauth
+
+define i32 @bar() #0 {
+  ret i32 42
+}
+
+define i32 @foo() {
+  %tmp = call i32 @bar()
+  ret i32 %tmp
+}
+
+attributes #0 = { "ptrauth-returns" "target-cpu"="generic" }
+
+;--- auth-call.ll
+
+; RUN: not --crash llc -mtriple aarch64-elf auth-call.ll 2>&1 | \
+; RUN:   FileCheck auth-call.ll
+
+; CHECK: LLVM ERROR: Cannot select:{{.*}}AArch64ISD::AUTH_CALL
+
+define void @bar(ptr %foo) #0 {
+  call void %foo() [ "ptrauth"(i32 0, i64 0) ]
+  ret void
+}
+
+attributes #0 = { "ptrauth-calls" "target-cpu"="generic" }
+
+;--- tryAuthLoad.ll
+
+; RUN: not --crash llc -mtriple aarch64-elf tryAuthLoad.ll 2>&1 | \
+; RUN:   FileCheck tryAuthLoad.ll
+
+; CHECK: LLVM ERROR: pac instructions require ptrauth target feature
+
+define i64 @test(ptr %ptr) {
+  %tmp0 = ptrtoint ptr %ptr to i64
+  %tmp1 = call i64 @llvm.ptrauth.auth(i64 %tmp0, i32 2, i64 0)
+  %tmp2 = inttoptr i64 %tmp1 to ptr
+  %tmp3 = load i64, ptr %tmp2
+  ret i64 %tmp3
+}
+
+declare i64 @llvm.ptrauth.auth(i64, i32, i64)