From fd64c3a7419dc5a53e97e5de1942eb7ceb889ff2 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Tue, 29 Jun 2021 10:31:58 -0700 Subject: [PATCH] [Inline] prevent inlining on noprofile mismatch Similar to commit bc044a88ee3c ("[Inline] prevent inlining on stack protector mismatch") The noprofile function attribute is meant to prevent compiler instrumentation from being inserted into a function. Inlining may defeat the developer's intent. If the caller and callee don't either BOTH have the attribute or BOTH lack the attribute, suppress inline substitution. This matches behavior being proposed in GCC: https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573511.html https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80223 Add LangRef entry for noprofile fn attr, similar to text added in D93422 and D104944. Reviewed By: MaskRay, melver, phosek Differential Revision: https://reviews.llvm.org/D104810 --- docs/LangRef.rst | 4 ++ include/llvm/IR/Attributes.td | 1 + test/Transforms/Inline/inline_noprofile.ll | 44 ++++++++++++++++++++++ 3 files changed, 49 insertions(+) create mode 100644 test/Transforms/Inline/inline_noprofile.ll diff --git a/docs/LangRef.rst b/docs/LangRef.rst index 5bbcc1477c5..848ee2343b5 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -1656,6 +1656,10 @@ example: This attribute suppresses lazy symbol binding for the function. This may make calls to the function faster, at the cost of extra program startup time if the function is not called during program startup. +``noprofile`` + This function attribute prevents instrumentation based profiling, used for + coverage or profile based optimization, from being added to a function, + even when inlined. ``noredzone`` This attribute indicates that the code generator should not use a red zone, even if the target-specific ABI normally permits it. diff --git a/include/llvm/IR/Attributes.td b/include/llvm/IR/Attributes.td index 177471c69fa..b3ea4f0b873 100644 --- a/include/llvm/IR/Attributes.td +++ b/include/llvm/IR/Attributes.td @@ -297,6 +297,7 @@ def : CompatRule<"isEqual">; def : CompatRule<"isEqual">; def : CompatRule<"isEqual">; def : CompatRule<"isEqual">; +def : CompatRule<"isEqual">; class MergeRule { // The name of the function called to merge the attributes of the caller and diff --git a/test/Transforms/Inline/inline_noprofile.ll b/test/Transforms/Inline/inline_noprofile.ll new file mode 100644 index 00000000000..dd023b20126 --- /dev/null +++ b/test/Transforms/Inline/inline_noprofile.ll @@ -0,0 +1,44 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt -passes=inline %s -S -pass-remarks-missed=inline 2>&1 | FileCheck %s --check-prefixes=CHECK,CHECK-INLINE +; RUN: opt -passes=always-inline %s -S | FileCheck %s + +; Test that we don't inline when caller and callee don't have matching +; noprofile fn attrs. + +; CHECK-INLINE: profile not inlined into profile_caller because it should never be inlined (cost=never): conflicting attributes +; CHECK-INLINE: noprofile not inlined into noprofile_caller because it should never be inlined (cost=never): conflicting attributes + +define i32 @profile() { ret i32 42 } +define i32 @noprofile() noprofile { ret i32 43 } +define i32 @profile_aa() alwaysinline { ret i32 44 } +define i32 @noprofile_aa() noprofile alwaysinline { ret i32 45 } + +define i32 @profile_caller() noprofile { +; CHECK-LABEL: @profile_caller( +; CHECK-NEXT: [[TMP1:%.*]] = call i32 @profile() +; CHECK-NEXT: ret i32 44 +; + call i32 @profile() + %2 = call i32 @profile_aa() + ret i32 %2 +} + +define i32 @noprofile_caller() { +; CHECK-LABEL: @noprofile_caller( +; CHECK-NEXT: [[TMP1:%.*]] = call i32 @noprofile() +; CHECK-NEXT: ret i32 45 +; + call i32 @noprofile() + %2 = call i32 @noprofile_aa() + ret i32 %2 +} + +; Test that we do inline when caller and callee don't have matching +; noprofile fn attrs, when CallInst is alwaysinline. +define i32 @aa_callsite() { +; CHECK-INLINE-LABEL: @aa_callsite( +; CHECK-INLINE-NEXT: ret i32 43 +; + %1 = call i32 @noprofile() alwaysinline + ret i32 %1 +}