[llvm] [InstCombine] Combine ptrauth constants into ptrauth intrinsics. (PR #94705)
Ahmed Bougacha via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 26 18:49:09 PDT 2024
https://github.com/ahmedbougacha updated https://github.com/llvm/llvm-project/pull/94705
>From 9dfe0109cc6c3c74edb2a3ad4e7de7aea3e615e1 Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Mon, 27 Sep 2021 08:00:00 -0700
Subject: [PATCH 1/3] [InstCombine] Combine ptrauth constants into ptrauth
intrinsics.
When we encounter two consecutive ptrauth intrinsics, we can
already combine the inner matching sign + auth pair, e.g.:
resign(sign(p,ks,ds),ks,ds,kr,dr) -> sign(p,kr,dr)
We can generalize that to ptrauth constants, which are effectively
constant equivalents to ptrauth.sign, i.e.:
resign(ptrauth(p,ks,ds),ks,ds,kr,dr) -> ptrauth(p,kr,dr)
auth(ptrauth(p,k,d),k,d) -> p
While there cleanup a redundant return after eraseInstFromFunction
in the shared (intrinsic|constant)->intrinsic folding code.
---
.../InstCombine/InstCombineCalls.cpp | 27 ++++++-
.../InstCombine/ptrauth-intrinsics.ll | 73 +++++++++++++++++++
2 files changed, 97 insertions(+), 3 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 436cdbff75669..310514bea3ec1 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2643,13 +2643,14 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
// (sign|resign) + (auth|resign) can be folded by omitting the middle
// sign+auth component if the key and discriminator match.
bool NeedSign = II->getIntrinsicID() == Intrinsic::ptrauth_resign;
+ Value *Ptr = II->getArgOperand(0);
Value *Key = II->getArgOperand(1);
Value *Disc = II->getArgOperand(2);
// AuthKey will be the key we need to end up authenticating against in
// whatever we replace this sequence with.
Value *AuthKey = nullptr, *AuthDisc = nullptr, *BasePtr;
- if (auto CI = dyn_cast<CallBase>(II->getArgOperand(0))) {
+ if (auto *CI = dyn_cast<CallBase>(Ptr)) {
BasePtr = CI->getArgOperand(0);
if (CI->getIntrinsicID() == Intrinsic::ptrauth_sign) {
if (CI->getArgOperand(1) != Key || CI->getArgOperand(2) != Disc)
@@ -2661,6 +2662,27 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
AuthDisc = CI->getArgOperand(2);
} else
break;
+ } else if (auto *PtrToInt = dyn_cast<PtrToIntOperator>(Ptr)) {
+ // ptrauth constants are equivalent to a call to @llvm.ptrauth.sign for
+ // our purposes, so check for that too.
+ auto *CPA = dyn_cast<ConstantPtrAuth>(PtrToInt->getOperand(0));
+ if (!CPA || !CPA->isKnownCompatibleWith(Key, Disc, DL))
+ break;
+
+ // resign(ptrauth(p,ks,ds),ks,ds,kr,dr) -> ptrauth(p,kr,dr)
+ if (NeedSign && isa<ConstantInt>(II->getArgOperand(4))) {
+ auto *SignKey = cast<ConstantInt>(II->getArgOperand(3));
+ auto *SignDisc = cast<ConstantInt>(II->getArgOperand(4));
+ auto *SignAddrDisc = ConstantPointerNull::get(Builder.getPtrTy());
+ auto *NewCPA = ConstantPtrAuth::get(CPA->getPointer(), SignKey,
+ SignDisc, SignAddrDisc);
+ replaceInstUsesWith(
+ *II, ConstantExpr::getPointerCast(NewCPA, II->getType()));
+ return eraseInstFromFunction(*II);
+ }
+
+ // auth(ptrauth(p,k,d),k,d) -> p
+ BasePtr = Builder.CreatePtrToInt(CPA->getPointer(), II->getType());
} else
break;
@@ -2677,8 +2699,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
} else {
// sign(0) + auth(0) = nop
replaceInstUsesWith(*II, BasePtr);
- eraseInstFromFunction(*II);
- return nullptr;
+ return eraseInstFromFunction(*II);
}
SmallVector<Value *, 4> CallArgs;
diff --git a/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll b/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
index da0f724abfde4..3e894739f4e34 100644
--- a/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
@@ -12,6 +12,26 @@ define i64 @test_ptrauth_nop(ptr %p) {
ret i64 %authed
}
+declare void @foo()
+
+define i64 @test_ptrauth_nop_constant() {
+; CHECK-LABEL: @test_ptrauth_nop_constant(
+; CHECK-NEXT: ret i64 ptrtoint (ptr @foo to i64)
+;
+ %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234) to i64), i32 1, i64 1234)
+ ret i64 %authed
+}
+
+define i64 @test_ptrauth_nop_constant_addrdisc() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_addrdisc(
+; CHECK-NEXT: ret i64 ptrtoint (ptr @foo to i64)
+;
+ %addr = ptrtoint void()* @foo to i64
+ %blended = call i64 @llvm.ptrauth.blend(i64 %addr, i64 1234)
+ %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 %blended)
+ ret i64 %authed
+}
+
define i64 @test_ptrauth_nop_mismatch(ptr %p) {
; CHECK-LABEL: @test_ptrauth_nop_mismatch(
; CHECK-NEXT: [[TMP0:%.*]] = ptrtoint ptr [[P:%.*]] to i64
@@ -87,6 +107,59 @@ define i64 @test_ptrauth_resign_auth_mismatch(ptr %p) {
ret i64 %authed
}
+define i64 @test_ptrauth_nop_constant_mismatch() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_mismatch(
+; CHECK-NEXT: [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234) to i64), i32 1, i64 12)
+; CHECK-NEXT: ret i64 [[AUTHED]]
+;
+ %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234) to i64), i32 1, i64 12)
+ ret i64 %authed
+}
+
+define i64 @test_ptrauth_nop_constant_mismatch_key() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_mismatch_key(
+; CHECK-NEXT: [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234) to i64), i32 0, i64 1234)
+; CHECK-NEXT: ret i64 [[AUTHED]]
+;
+ %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234) to i64), i32 0, i64 1234)
+ ret i64 %authed
+}
+
+define i64 @test_ptrauth_nop_constant_addrdisc_mismatch() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_addrdisc_mismatch(
+; CHECK-NEXT: [[BLENDED:%.*]] = call i64 @llvm.ptrauth.blend(i64 ptrtoint (ptr @foo to i64), i64 12)
+; CHECK-NEXT: [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 [[BLENDED]])
+; CHECK-NEXT: ret i64 [[AUTHED]]
+;
+ %addr = ptrtoint ptr @foo to i64
+ %blended = call i64 @llvm.ptrauth.blend(i64 %addr, i64 12)
+ %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 %blended)
+ ret i64 %authed
+}
+
+define i64 @test_ptrauth_nop_constant_addrdisc_mismatch2() {
+; CHECK-LABEL: @test_ptrauth_nop_constant_addrdisc_mismatch2(
+; CHECK-NEXT: [[BLENDED:%.*]] = call i64 @llvm.ptrauth.blend(i64 ptrtoint (ptr @test_ptrauth_nop to i64), i64 1234)
+; CHECK-NEXT: [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 [[BLENDED]])
+; CHECK-NEXT: ret i64 [[AUTHED]]
+;
+ %addr = ptrtoint ptr @test_ptrauth_nop to i64
+ %blended = call i64 @llvm.ptrauth.blend(i64 %addr, i64 1234)
+ %authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 %blended)
+ ret i64 %authed
+}
+
+define i64 @test_ptrauth_resign_ptrauth_constant(ptr %p) {
+; CHECK-LABEL: @test_ptrauth_resign_ptrauth_constant(
+; CHECK-NEXT: ret i64 ptrtoint (ptr ptrauth (ptr @foo, i32 0, i64 42) to i64)
+;
+
+ %tmp0 = ptrtoint ptr %p to i64
+ %authed = call i64 @llvm.ptrauth.resign(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234) to i64), i32 1, i64 1234, i32 0, i64 42)
+ ret i64 %authed
+}
+
declare i64 @llvm.ptrauth.auth(i64, i32, i64)
declare i64 @llvm.ptrauth.sign(i64, i32, i64)
declare i64 @llvm.ptrauth.resign(i64, i32, i64, i32, i64)
+declare i64 @llvm.ptrauth.blend(i64, i64)
>From 4943d02d4ec5ea311ce9db55858ae895cc313601 Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Thu, 13 Jun 2024 13:34:45 -0700
Subject: [PATCH 2/3] Replace typed pointers in casts with ptr.
---
llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll b/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
index 3e894739f4e34..609abbe3a0d72 100644
--- a/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
@@ -26,7 +26,7 @@ define i64 @test_ptrauth_nop_constant_addrdisc() {
; CHECK-LABEL: @test_ptrauth_nop_constant_addrdisc(
; CHECK-NEXT: ret i64 ptrtoint (ptr @foo to i64)
;
- %addr = ptrtoint void()* @foo to i64
+ %addr = ptrtoint ptr @foo to i64
%blended = call i64 @llvm.ptrauth.blend(i64 %addr, i64 1234)
%authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 %blended)
ret i64 %authed
>From b08be11498e0e786606f9da20cfa7f813c9c3953 Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Wed, 26 Jun 2024 18:47:45 -0700
Subject: [PATCH 3/3] Address review feedback.
- don't reuse fn in test
- const
---
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp | 6 +++---
llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll | 5 +++--
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 310514bea3ec1..b42f0ca296fc5 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2650,7 +2650,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
// AuthKey will be the key we need to end up authenticating against in
// whatever we replace this sequence with.
Value *AuthKey = nullptr, *AuthDisc = nullptr, *BasePtr;
- if (auto *CI = dyn_cast<CallBase>(Ptr)) {
+ if (const auto *CI = dyn_cast<CallBase>(Ptr)) {
BasePtr = CI->getArgOperand(0);
if (CI->getIntrinsicID() == Intrinsic::ptrauth_sign) {
if (CI->getArgOperand(1) != Key || CI->getArgOperand(2) != Disc)
@@ -2662,10 +2662,10 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
AuthDisc = CI->getArgOperand(2);
} else
break;
- } else if (auto *PtrToInt = dyn_cast<PtrToIntOperator>(Ptr)) {
+ } else if (const auto *PtrToInt = dyn_cast<PtrToIntOperator>(Ptr)) {
// ptrauth constants are equivalent to a call to @llvm.ptrauth.sign for
// our purposes, so check for that too.
- auto *CPA = dyn_cast<ConstantPtrAuth>(PtrToInt->getOperand(0));
+ const auto *CPA = dyn_cast<ConstantPtrAuth>(PtrToInt->getOperand(0));
if (!CPA || !CPA->isKnownCompatibleWith(Key, Disc, DL))
break;
diff --git a/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll b/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
index 609abbe3a0d72..208e162ac9416 100644
--- a/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/ptrauth-intrinsics.ll
@@ -13,6 +13,7 @@ define i64 @test_ptrauth_nop(ptr %p) {
}
declare void @foo()
+declare void @bar()
define i64 @test_ptrauth_nop_constant() {
; CHECK-LABEL: @test_ptrauth_nop_constant(
@@ -139,11 +140,11 @@ define i64 @test_ptrauth_nop_constant_addrdisc_mismatch() {
define i64 @test_ptrauth_nop_constant_addrdisc_mismatch2() {
; CHECK-LABEL: @test_ptrauth_nop_constant_addrdisc_mismatch2(
-; CHECK-NEXT: [[BLENDED:%.*]] = call i64 @llvm.ptrauth.blend(i64 ptrtoint (ptr @test_ptrauth_nop to i64), i64 1234)
+; CHECK-NEXT: [[BLENDED:%.*]] = call i64 @llvm.ptrauth.blend(i64 ptrtoint (ptr @bar to i64), i64 1234)
; CHECK-NEXT: [[AUTHED:%.*]] = call i64 @llvm.ptrauth.auth(i64 ptrtoint (ptr ptrauth (ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 [[BLENDED]])
; CHECK-NEXT: ret i64 [[AUTHED]]
;
- %addr = ptrtoint ptr @test_ptrauth_nop to i64
+ %addr = ptrtoint ptr @bar to i64
%blended = call i64 @llvm.ptrauth.blend(i64 %addr, i64 1234)
%authed = call i64 @llvm.ptrauth.auth(i64 ptrtoint(ptr ptrauth(ptr @foo, i32 1, i64 1234, ptr @foo) to i64), i32 1, i64 %blended)
ret i64 %authed
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