[llvm-branch-commits] [LowerAllowCheck] Add llvm.allow.sanitize.* intrinsics (PR #172029)
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llvm-branch-commits at lists.llvm.org
Fri Dec 12 08:06:51 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-ir
Author: Marco Elver (melver)
<details>
<summary>Changes</summary>
Add new intrinsics:
- llvm.allow.sanitize.address
- llvm.allow.sanitize.thread
- llvm.allow.sanitize.memory
- llvm.allow.sanitize.hwaddress
These intrinsics return true if the corresponding sanitizer is enabled
for the function, and false otherwise. They are lowered by
LowerAllowCheckPass to constant booleans based on the corresponding
sanitize_* function attributes. LowerAllowCheckPass is now "required" to
run on functions with optnone to ensure correct lowering at O0.
The LowerAllowCheckPass already performs similar duties for
@<!-- -->llvm.allow.runtime.check and @<!-- -->llvm.allow.ubsan.check, although with
subtly different semantics (based on profiles and/or sampling). In this
case, we want to make the true/false decision based on if any one of
address/memory/thread sanitization is enabled.
---
This change is part of the series:
* https://github.com/llvm/llvm-project/pull/172028
* https://github.com/llvm/llvm-project/pull/172029
* https://github.com/llvm/llvm-project/pull/172030
---
Full diff: https://github.com/llvm/llvm-project/pull/172029.diff
4 Files Affected:
- (modified) llvm/include/llvm/IR/Intrinsics.td (+14)
- (modified) llvm/include/llvm/Transforms/Instrumentation/LowerAllowCheckPass.h (+2)
- (modified) llvm/lib/Transforms/Instrumentation/LowerAllowCheckPass.cpp (+22-6)
- (added) llvm/test/Transforms/LowerAllowCheck/sanitize-check.ll (+70)
``````````diff
diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
index 35a4158a56da9..c8e16178b7a02 100644
--- a/llvm/include/llvm/IR/Intrinsics.td
+++ b/llvm/include/llvm/IR/Intrinsics.td
@@ -1884,6 +1884,20 @@ def int_allow_runtime_check : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_metadata
[IntrInaccessibleMemOnly, NoUndef<RetIndex>]>,
ClangBuiltin<"__builtin_allow_runtime_check">;
+// Return true if the specific sanitizer is enabled for the function.
+def int_allow_sanitize_address
+ : DefaultAttrsIntrinsic<[llvm_i1_ty], [],
+ [IntrInaccessibleMemOnly, NoUndef<RetIndex>]>;
+def int_allow_sanitize_thread
+ : DefaultAttrsIntrinsic<[llvm_i1_ty], [],
+ [IntrInaccessibleMemOnly, NoUndef<RetIndex>]>;
+def int_allow_sanitize_memory
+ : DefaultAttrsIntrinsic<[llvm_i1_ty], [],
+ [IntrInaccessibleMemOnly, NoUndef<RetIndex>]>;
+def int_allow_sanitize_hwaddress
+ : DefaultAttrsIntrinsic<[llvm_i1_ty], [],
+ [IntrInaccessibleMemOnly, NoUndef<RetIndex>]>;
+
// Support for dynamic deoptimization (or de-specialization)
def int_experimental_deoptimize : Intrinsic<[llvm_any_ty], [llvm_vararg_ty],
[Throws]>;
diff --git a/llvm/include/llvm/Transforms/Instrumentation/LowerAllowCheckPass.h b/llvm/include/llvm/Transforms/Instrumentation/LowerAllowCheckPass.h
index 37bc728779836..7b5e4a21c057c 100644
--- a/llvm/include/llvm/Transforms/Instrumentation/LowerAllowCheckPass.h
+++ b/llvm/include/llvm/Transforms/Instrumentation/LowerAllowCheckPass.h
@@ -34,6 +34,8 @@ class LowerAllowCheckPass : public PassInfoMixin<LowerAllowCheckPass> {
: Opts(std::move(Opts)) {};
LLVM_ABI PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+ static bool isRequired() { return true; }
+
LLVM_ABI static bool IsRequested();
LLVM_ABI void
printPipeline(raw_ostream &OS,
diff --git a/llvm/lib/Transforms/Instrumentation/LowerAllowCheckPass.cpp b/llvm/lib/Transforms/Instrumentation/LowerAllowCheckPass.cpp
index 2486e77ab0137..d4c23ffe9a723 100644
--- a/llvm/lib/Transforms/Instrumentation/LowerAllowCheckPass.cpp
+++ b/llvm/lib/Transforms/Instrumentation/LowerAllowCheckPass.cpp
@@ -76,6 +76,7 @@ static bool lowerAllowChecks(Function &F, const BlockFrequencyInfo &BFI,
const ProfileSummaryInfo *PSI,
OptimizationRemarkEmitter &ORE,
const LowerAllowCheckPass::Options &Opts) {
+ // List of intrinsics and the constant value they should be lowered to.
SmallVector<std::pair<IntrinsicInst *, bool>, 16> ReplaceWithValue;
std::unique_ptr<RandomNumberGenerator> Rng;
@@ -123,26 +124,41 @@ static bool lowerAllowChecks(Function &F, const BlockFrequencyInfo &BFI,
switch (ID) {
case Intrinsic::allow_ubsan_check:
case Intrinsic::allow_runtime_check: {
- ++NumChecksTotal;
-
bool ToRemove = ShouldRemove(II);
ReplaceWithValue.push_back({
II,
- ToRemove,
+ !ToRemove,
});
- if (ToRemove)
- ++NumChecksRemoved;
emitRemark(II, ORE, ToRemove);
break;
}
+ case Intrinsic::allow_sanitize_address:
+ ReplaceWithValue.push_back(
+ {II, F.hasFnAttribute(Attribute::SanitizeAddress)});
+ break;
+ case Intrinsic::allow_sanitize_thread:
+ ReplaceWithValue.push_back(
+ {II, F.hasFnAttribute(Attribute::SanitizeThread)});
+ break;
+ case Intrinsic::allow_sanitize_memory:
+ ReplaceWithValue.push_back(
+ {II, F.hasFnAttribute(Attribute::SanitizeMemory)});
+ break;
+ case Intrinsic::allow_sanitize_hwaddress:
+ ReplaceWithValue.push_back(
+ {II, F.hasFnAttribute(Attribute::SanitizeHWAddress)});
+ break;
default:
break;
}
}
for (auto [I, V] : ReplaceWithValue) {
- I->replaceAllUsesWith(ConstantInt::getBool(I->getType(), !V));
+ ++NumChecksTotal;
+ if (!V) // If the final value is false, the check is considered removed
+ ++NumChecksRemoved;
+ I->replaceAllUsesWith(ConstantInt::getBool(I->getType(), V));
I->eraseFromParent();
}
diff --git a/llvm/test/Transforms/LowerAllowCheck/sanitize-check.ll b/llvm/test/Transforms/LowerAllowCheck/sanitize-check.ll
new file mode 100644
index 0000000000000..eb3c6073aabe5
--- /dev/null
+++ b/llvm/test/Transforms/LowerAllowCheck/sanitize-check.ll
@@ -0,0 +1,70 @@
+; RUN: opt < %s -passes=lower-allow-check -S | FileCheck %s
+; RUN: opt < %s -passes=lower-allow-check -lower-allow-check-random-rate=0 -S | FileCheck %s
+
+declare i1 @llvm.allow.sanitize.address()
+declare i1 @llvm.allow.sanitize.thread()
+declare i1 @llvm.allow.sanitize.memory()
+declare i1 @llvm.allow.sanitize.hwaddress()
+
+define i1 @test_address() sanitize_address {
+; CHECK-LABEL: @test_address(
+; CHECK-NEXT: ret i1 true
+ %1 = call i1 @llvm.allow.sanitize.address()
+ ret i1 %1
+}
+
+define i1 @test_no_sanitize_address() {
+; CHECK-LABEL: @test_no_sanitize_address(
+; CHECK-NEXT: ret i1 false
+ %1 = call i1 @llvm.allow.sanitize.address()
+ ret i1 %1
+}
+
+define i1 @test_address_but_no_thread() sanitize_address {
+; CHECK-LABEL: @test_address_but_no_thread(
+; CHECK-NEXT: ret i1 false
+ %1 = call i1 @llvm.allow.sanitize.thread()
+ ret i1 %1
+}
+
+define i1 @test_thread() sanitize_thread {
+; CHECK-LABEL: @test_thread(
+; CHECK-NEXT: ret i1 true
+ %1 = call i1 @llvm.allow.sanitize.thread()
+ ret i1 %1
+}
+
+define i1 @test_no_sanitize_thread() {
+; CHECK-LABEL: @test_no_sanitize_thread(
+; CHECK-NEXT: ret i1 false
+ %1 = call i1 @llvm.allow.sanitize.thread()
+ ret i1 %1
+}
+
+define i1 @test_memory() sanitize_memory {
+; CHECK-LABEL: @test_memory(
+; CHECK-NEXT: ret i1 true
+ %1 = call i1 @llvm.allow.sanitize.memory()
+ ret i1 %1
+}
+
+define i1 @test_no_sanitize_memory() {
+; CHECK-LABEL: @test_no_sanitize_memory(
+; CHECK-NEXT: ret i1 false
+ %1 = call i1 @llvm.allow.sanitize.memory()
+ ret i1 %1
+}
+
+define i1 @test_hwaddress() sanitize_hwaddress {
+; CHECK-LABEL: @test_hwaddress(
+; CHECK-NEXT: ret i1 true
+ %1 = call i1 @llvm.allow.sanitize.hwaddress()
+ ret i1 %1
+}
+
+define i1 @test_no_sanitize_hwaddress() {
+; CHECK-LABEL: @test_no_sanitize_hwaddress(
+; CHECK-NEXT: ret i1 false
+ %1 = call i1 @llvm.allow.sanitize.hwaddress()
+ ret i1 %1
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/172029
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