llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-codegen Author: None (davidtrevelyan) <details> <summary>Changes</summary> # Clang CodeGen for [[clang::blocking]] with RTSan Follows https://github.com/llvm/llvm-project/pull/106754 and https://github.com/llvm/llvm-project/pull/109543. This is the final patch for the feature. ## Motivation Calls to system library functions such as malloc are easy for RealtimeSanitizer to intercept. If such a call is made in a [[clang::nonblocking]] function (a real-time context), RealtimeSanitizer will error. Real-time programmers also write their own blocking (real-time unsafe) functions that may or may not call intercepted functions. We wish to introduce a mechanism whereby RealtimeSanitizer can error on calls to these, too, if called within a real-time context. At the same time as introducing [[clang::nonblocking]], the [[clang::blocking]] attribute was also introduced. With the function effects warnings (as errors) activated, blocking functions cannot be called from non-blocking functions, and this is enforced at compile time. The purpose of this series of PRs is to introduce similar functionality into RealtimeSanitizer, so that it can make the equivalent check at run time. ## Implementation We recently merged the `sanitize_realtime_unsafe` LLVM function attribute into `main`, as well as the LLVM pass to notify the sanitizer runtime of the blocking call. Our final step is to switch on the feature by updating Clang's CodeGen. This patch just adds the `sanitize_realtime_unsafe` attribute to the IR for functions attributed with `[[clang::blocking]]`. Once the feature is switched on, RealtimeSanitizer will error if any calls to functions attributed with `[[clang::blocking]]` are made from `[[clang::nonblocking]]` functions. ## Integration Roadmap The above functionality is currently split into three patches. - [x] https://github.com/llvm/llvm-project/pull/106754, - [x] https://github.com/llvm/llvm-project/pull/109543, and - [ ] An update to Clang's CodeGen to add the `sanitize_realtime_unsafe` attribute to functions attributed with `[[clang::blocking]]` (this PR) --- Full diff: https://github.com/llvm/llvm-project/pull/111055.diff 3 Files Affected: - (modified) clang/lib/CodeGen/CodeGenFunction.cpp (+2) - (modified) clang/test/CodeGen/rtsan_attribute_inserted.c (+7-3) - (modified) clang/test/CodeGen/rtsan_no_attribute_sanitizer_disabled.c (+4-2) ``````````diff diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp index 24723e392c2a3a..e1fd9b72b8d7b2 100644 --- a/clang/lib/CodeGen/CodeGenFunction.cpp +++ b/clang/lib/CodeGen/CodeGenFunction.cpp @@ -850,6 +850,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, for (const FunctionEffectWithCondition &Fe : FD->getFunctionEffects()) { if (Fe.Effect.kind() == FunctionEffect::Kind::NonBlocking) Fn->addFnAttr(llvm::Attribute::SanitizeRealtime); + else if (Fe.Effect.kind() == FunctionEffect::Kind::Blocking) + Fn->addFnAttr(llvm::Attribute::SanitizeRealtimeUnsafe); } // Apply fuzzing attribute to the function. diff --git a/clang/test/CodeGen/rtsan_attribute_inserted.c b/clang/test/CodeGen/rtsan_attribute_inserted.c index 05a1d9a8c2047a..b21ecb6b6b06a9 100644 --- a/clang/test/CodeGen/rtsan_attribute_inserted.c +++ b/clang/test/CodeGen/rtsan_attribute_inserted.c @@ -1,7 +1,11 @@ // RUN: %clang_cc1 -triple x86_64-unknown-linux -fsanitize=realtime %s -emit-llvm -o - %s | FileCheck %s float process(float *a) [[clang::nonblocking]] { return *a; } - -// CHECK-LABEL: @process{{.*}}#0 { +// CHECK: @process{{.*}} #0 { // CHECK: attributes #0 = { -// CHECK-SAME: {{.*sanitize_realtime.*}} +// CHECK-SAME: {{.*sanitize_realtime .*}} + +int spinlock(int *a) [[clang::blocking]] { return *a; } +// CHECK: @spinlock{{.*}} #1 { +// CHECK: attributes #1 = { +// CHECK-SAME: {{.*sanitize_realtime_unsafe .*}} diff --git a/clang/test/CodeGen/rtsan_no_attribute_sanitizer_disabled.c b/clang/test/CodeGen/rtsan_no_attribute_sanitizer_disabled.c index 43ad6ed1a429ee..0f43007c5e4c16 100644 --- a/clang/test/CodeGen/rtsan_no_attribute_sanitizer_disabled.c +++ b/clang/test/CodeGen/rtsan_no_attribute_sanitizer_disabled.c @@ -1,6 +1,8 @@ // RUN: %clang_cc1 -triple aarch64-unknown-linux-gnu -emit-llvm -o - %s | FileCheck %s float process(float *a) [[clang::nonblocking]] { return *a; } +int spinlock(int *a) [[clang::blocking]] { return *a; } -// Without the -fsanitize=realtime flag, we shouldn't attach the attribute. -// CHECK-NOT: {{.*sanitize_realtime.*}} +// Without the -fsanitize=realtime flag, we shouldn't attach the attributes. +// CHECK-NOT: {{.*sanitize_realtime .*}} +// CHECK-NOT: {{.*sanitize_realtime_unsafe .*}} `````````` </details> https://github.com/llvm/llvm-project/pull/111055 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
