[clang] 12e78ff - [InstrProf] Add the skipprofile attribute
Ellis Hoag via cfe-commits
cfe-commits at lists.llvm.org
Thu Aug 4 08:45:33 PDT 2022
Author: Ellis Hoag
Date: 2022-08-04T08:45:27-07:00
New Revision: 12e78ff88105f2dc6cb1449d6fcd5d8f69e0512f
URL: https://github.com/llvm/llvm-project/commit/12e78ff88105f2dc6cb1449d6fcd5d8f69e0512f
DIFF: https://github.com/llvm/llvm-project/commit/12e78ff88105f2dc6cb1449d6fcd5d8f69e0512f.diff
LOG: [InstrProf] Add the skipprofile attribute
As discussed in [0], this diff adds the `skipprofile` attribute to
prevent the function from being profiled while allowing profiled
functions to be inlined into it. The `noprofile` attribute remains
unchanged.
The `noprofile` attribute is used for functions where it is
dangerous to add instrumentation to while the `skipprofile` attribute is
used to reduce code size or performance overhead.
[0] https://discourse.llvm.org/t/why-does-the-noprofile-attribute-restrict-inlining/64108
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D130807
Added:
Modified:
clang/lib/CodeGen/CodeGenFunction.h
clang/lib/CodeGen/CodeGenPGO.cpp
clang/test/CodeGen/profile-function-groups.c
llvm/docs/LangRef.rst
llvm/include/llvm/Bitcode/LLVMBitCodes.h
llvm/include/llvm/IR/Attributes.td
llvm/lib/Bitcode/Reader/BitcodeReader.cpp
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
llvm/lib/Transforms/Utils/CodeExtractor.cpp
llvm/test/Bitcode/attributes.ll
llvm/test/Transforms/GCOVProfiling/noprofile.ll
llvm/test/Transforms/PGOProfile/noprofile.ll
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index b61a2a68687d9..30cf162e36206 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -1522,7 +1522,8 @@ class CodeGenFunction : public CodeGenTypeCache {
/// If \p StepV is null, the default increment is 1.
void incrementProfileCounter(const Stmt *S, llvm::Value *StepV = nullptr) {
if (CGM.getCodeGenOpts().hasProfileClangInstr() &&
- !CurFn->hasFnAttribute(llvm::Attribute::NoProfile))
+ !CurFn->hasFnAttribute(llvm::Attribute::NoProfile) &&
+ !CurFn->hasFnAttribute(llvm::Attribute::SkipProfile))
PGO.emitCounterIncrement(Builder, S, StepV);
PGO.setCurrentStmt(S);
}
diff --git a/clang/lib/CodeGen/CodeGenPGO.cpp b/clang/lib/CodeGen/CodeGenPGO.cpp
index 587bcef78ee51..03531e32f1267 100644
--- a/clang/lib/CodeGen/CodeGenPGO.cpp
+++ b/clang/lib/CodeGen/CodeGenPGO.cpp
@@ -822,6 +822,8 @@ void CodeGenPGO::assignRegionCounters(GlobalDecl GD, llvm::Function *Fn) {
CGM.ClearUnusedCoverageMapping(D);
if (Fn->hasFnAttribute(llvm::Attribute::NoProfile))
return;
+ if (Fn->hasFnAttribute(llvm::Attribute::SkipProfile))
+ return;
setFuncName(Fn);
diff --git a/clang/test/CodeGen/profile-function-groups.c b/clang/test/CodeGen/profile-function-groups.c
index 9e04c9060df48..232abd767a8fd 100644
--- a/clang/test/CodeGen/profile-function-groups.c
+++ b/clang/test/CodeGen/profile-function-groups.c
@@ -1,9 +1,9 @@
-// RUN: %clang -fprofile-generate -fprofile-function-groups=3 -fprofile-selected-function-group=0 -emit-llvm -S %s -o - | FileCheck %s --check-prefixes=CHECK,SELECT0
-// RUN: %clang -fprofile-generate -fprofile-function-groups=3 -fprofile-selected-function-group=1 -emit-llvm -S %s -o - | FileCheck %s --check-prefixes=CHECK,SELECT1
-// RUN: %clang -fprofile-generate -fprofile-function-groups=3 -fprofile-selected-function-group=2 -emit-llvm -S %s -o - | FileCheck %s --check-prefixes=CHECK,SELECT2
+// RUN: %clang -fprofile-generate -fprofile-function-groups=3 -fprofile-selected-function-group=0 -emit-llvm -S %s -o - | FileCheck %s --implicit-check-not="; {{.* (noprofile|skipprofile)}}" --check-prefixes=CHECK,SELECT0
+// RUN: %clang -fprofile-generate -fprofile-function-groups=3 -fprofile-selected-function-group=1 -emit-llvm -S %s -o - | FileCheck %s --implicit-check-not="; {{.* (noprofile|skipprofile)}}" --check-prefixes=CHECK,SELECT1
+// RUN: %clang -fprofile-generate -fprofile-function-groups=3 -fprofile-selected-function-group=2 -emit-llvm -S %s -o - | FileCheck %s --implicit-check-not="; {{.* (noprofile|skipprofile)}}" --check-prefixes=CHECK,SELECT2
// Group 0
-// SELECT0-NOT: noprofile
+
// SELECT1: noprofile
// SELECT2: noprofile
// CHECK: define {{.*}} @hoo()
@@ -11,7 +11,7 @@ void hoo() {}
// Group 1
// SELECT0: noprofile
-// SELECT1-NOT: noprofile
+
// SELECT2: noprofile
// CHECK: define {{.*}} @goo()
void goo() {}
@@ -19,6 +19,6 @@ void goo() {}
// Group 2
// SELECT0: noprofile
// SELECT1: noprofile
-// SELECT2-NOT: noprofile
+
// CHECK: define {{.*}} @boo()
void boo() {}
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 2abe628cee8f2..a3c0824f16c6c 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -1803,8 +1803,14 @@ example:
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.
+ coverage or profile based optimization, from being added to a function. It
+ also blocks inlining if the caller and callee have
diff erent values of this
+ attribute.
+``skipprofile``
+ This function attribute prevents instrumentation based profiling, used for
+ coverage or profile based optimization, from being added to a function. This
+ attribute does not restrict inlining, so instrumented instruction could end
+ up in this function.
``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/llvm/include/llvm/Bitcode/LLVMBitCodes.h b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
index eee4c50cc13bc..d26507a720491 100644
--- a/llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -689,6 +689,7 @@ enum AttributeKindCodes {
ATTR_KIND_ALLOC_KIND = 82,
ATTR_KIND_PRESPLIT_COROUTINE = 83,
ATTR_KIND_FNRETTHUNK_EXTERN = 84,
+ ATTR_KIND_SKIP_PROFILE = 85,
};
enum ComdatSelectionKindCodes {
diff --git a/llvm/include/llvm/IR/Attributes.td b/llvm/include/llvm/IR/Attributes.td
index ea4bf80205f86..642a39076c9b6 100644
--- a/llvm/include/llvm/IR/Attributes.td
+++ b/llvm/include/llvm/IR/Attributes.td
@@ -186,6 +186,10 @@ def NoCfCheck : EnumAttr<"nocf_check", [FnAttr]>;
/// Function should not be instrumented.
def NoProfile : EnumAttr<"noprofile", [FnAttr]>;
+/// This function should not be instrumented but it is ok to inline profiled
+// functions into it.
+def SkipProfile : EnumAttr<"skipprofile", [FnAttr]>;
+
/// Function doesn't unwind stack.
def NoUnwind : EnumAttr<"nounwind", [FnAttr]>;
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 343d49b4be9f4..379614b01740c 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1919,6 +1919,8 @@ static Attribute::AttrKind getAttrFromCode(uint64_t Code) {
return Attribute::NoCfCheck;
case bitc::ATTR_KIND_NO_PROFILE:
return Attribute::NoProfile;
+ case bitc::ATTR_KIND_SKIP_PROFILE:
+ return Attribute::SkipProfile;
case bitc::ATTR_KIND_NO_UNWIND:
return Attribute::NoUnwind;
case bitc::ATTR_KIND_NO_SANITIZE_BOUNDS:
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index eda4ac7bc039c..f66bc2d1dcc35 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -698,6 +698,8 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
return bitc::ATTR_KIND_NOCF_CHECK;
case Attribute::NoProfile:
return bitc::ATTR_KIND_NO_PROFILE;
+ case Attribute::SkipProfile:
+ return bitc::ATTR_KIND_SKIP_PROFILE;
case Attribute::NoUnwind:
return bitc::ATTR_KIND_NO_UNWIND;
case Attribute::NoSanitizeBounds:
diff --git a/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp b/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
index ac4a1fd6bb7ea..5939fe18fc647 100644
--- a/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -797,6 +797,8 @@ bool GCOVProfiler::emitProfileNotes(
if (isUsingScopeBasedEH(F)) continue;
if (F.hasFnAttribute(llvm::Attribute::NoProfile))
continue;
+ if (F.hasFnAttribute(llvm::Attribute::SkipProfile))
+ continue;
// Add the function line number to the lines of the entry block
// to have a counter for the function definition.
diff --git a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
index 90cc61c6b291b..b856772b13a86 100644
--- a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -1574,6 +1574,8 @@ static bool InstrumentAllFunctions(
continue;
if (F.hasFnAttribute(llvm::Attribute::NoProfile))
continue;
+ if (F.hasFnAttribute(llvm::Attribute::SkipProfile))
+ continue;
auto &TLI = LookupTLI(F);
auto *BPI = LookupBPI(F);
auto *BFI = LookupBFI(F);
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index 421f1f329f077..48e1f9ede62fb 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -963,6 +963,7 @@ Function *CodeExtractor::constructFunction(const ValueSet &inputs,
case Attribute::NoCfCheck:
case Attribute::MustProgress:
case Attribute::NoProfile:
+ case Attribute::SkipProfile:
break;
// These attributes cannot be applied to functions.
case Attribute::Alignment:
diff --git a/llvm/test/Bitcode/attributes.ll b/llvm/test/Bitcode/attributes.ll
index 78b54a5cf5c39..f8d31722acf07 100644
--- a/llvm/test/Bitcode/attributes.ll
+++ b/llvm/test/Bitcode/attributes.ll
@@ -535,6 +535,9 @@ define void @f86() nosanitize_bounds
; CHECK: define void @f87() [[FNRETTHUNKEXTERN:#[0-9]+]]
define void @f87() fn_ret_thunk_extern { ret void }
+; CHECK: define void @f88() [[SKIPPROFILE:#[0-9]+]]
+define void @f88() skipprofile { ret void }
+
; CHECK: attributes #0 = { noreturn }
; CHECK: attributes #1 = { nounwind }
; CHECK: attributes #2 = { readnone }
@@ -589,4 +592,5 @@ define void @f87() fn_ret_thunk_extern { ret void }
; CHECK: attributes #51 = { uwtable(sync) }
; CHECK: attributes #52 = { nosanitize_bounds }
; CHECK: attributes [[FNRETTHUNKEXTERN]] = { fn_ret_thunk_extern }
+; CHECK: attributes [[SKIPPROFILE]] = { skipprofile }
; CHECK: attributes #[[NOBUILTIN]] = { nobuiltin }
diff --git a/llvm/test/Transforms/GCOVProfiling/noprofile.ll b/llvm/test/Transforms/GCOVProfiling/noprofile.ll
index b1ce27e614a6d..b5dad493e59ec 100644
--- a/llvm/test/Transforms/GCOVProfiling/noprofile.ll
+++ b/llvm/test/Transforms/GCOVProfiling/noprofile.ll
@@ -10,6 +10,14 @@ define dso_local i32 @no_instr(i32 %a) noprofile !dbg !9 {
ret i32 42, !dbg !27
}
+; Test that the skipprofile attribute disables profiling.
+define dso_local i32 @skip_instr(i32 %a) skipprofile {
+; CHECK-LABEL: @skip_instr(
+; CHECK-NEXT: ret i32 52
+;
+ ret i32 52
+}
+
define dso_local i32 @instr(i32 %a) !dbg !28 {
; CHECK-LABEL: @instr(
; CHECK-NEXT: [[GCOV_CTR:%.*]] = load i64, ptr @__llvm_gcov_ctr, align 4, !dbg [[DBG8:![0-9]+]]
diff --git a/llvm/test/Transforms/PGOProfile/noprofile.ll b/llvm/test/Transforms/PGOProfile/noprofile.ll
index c8bdb673c1936..0da101afe1c9c 100644
--- a/llvm/test/Transforms/PGOProfile/noprofile.ll
+++ b/llvm/test/Transforms/PGOProfile/noprofile.ll
@@ -21,4 +21,10 @@ entry:
ret i32 %sub
}
+define i32 @test3() skipprofile {
+entry:
+; CHECK-NOT: call void @llvm.instrprof.increment
+ ret i32 101
+}
+
attributes #0 = { noprofile }
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