nickdesaulniers created this revision.
nickdesaulniers added reviewers: MaskRay, melver, void.
Herald added a subscriber: wenlei.
nickdesaulniers requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
noprofile IR attribute already exists to prevent profiling with PGO;
emit that when a function uses the no_instrument_function function
attribute.
The Linux kernel would like to avoid compiler generated code in
functions annotated with such attribute. We already respect this for
libcalls to fentry() and mcount().
Link:
https://lore.kernel.org/lkml/cakwvodmpti93n2l0_yqkrzldmpxzror7zggszonyaw2pgsh...@mail.gmail.com/
Signed-off-by: Nick Desaulniers <ndesaulni...@google.com>
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D104253
Files:
clang/lib/CodeGen/CodeGenFunction.cpp
clang/test/CodeGen/fprofile-generate.c
Index: clang/test/CodeGen/fprofile-generate.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/fprofile-generate.c
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -fprofile-instrument=llvm -emit-llvm -o - %s | FileCheck %s
+int g(int);
+
+int __attribute__((__no_instrument_function__))
+__attribute__((no_instrument_function))
+no_instr(int a) {
+// CHECK: define {{.*}} i32 @no_instr(i32 %a) [[ATTR:#[0-9]+]]
+ int sum = 0;
+ for (int i = 0; i < a; i++)
+ sum += g(i);
+ return sum;
+}
+
+int instr(int a) {
+// CHECK: define {{.*}} i32 @instr(i32 %a) [[ATTR2:#[0-9]+]]
+ int sum = 0;
+ for (int i = 0; i < a; i++)
+ sum += g(i);
+ return sum;
+}
+// CHECK: attributes [[ATTR]] = {{.*}} noprofile
+// CHECK-NOT: attributes [[ATTR2]] = {{.*}} noprofile
Index: clang/lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.cpp
+++ clang/lib/CodeGen/CodeGenFunction.cpp
@@ -893,6 +893,9 @@
if (D && D->hasAttr<CFICanonicalJumpTableAttr>())
Fn->addFnAttr("cfi-canonical-jump-table");
+ if (D && D->hasAttr<NoInstrumentFunctionAttr>())
+ Fn->addFnAttr(llvm::Attribute::NoProfile);
+
if (getLangOpts().OpenCL) {
// Add metadata for a kernel function.
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
Index: clang/test/CodeGen/fprofile-generate.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/fprofile-generate.c
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -fprofile-instrument=llvm -emit-llvm -o - %s | FileCheck %s
+int g(int);
+
+int __attribute__((__no_instrument_function__))
+__attribute__((no_instrument_function))
+no_instr(int a) {
+// CHECK: define {{.*}} i32 @no_instr(i32 %a) [[ATTR:#[0-9]+]]
+ int sum = 0;
+ for (int i = 0; i < a; i++)
+ sum += g(i);
+ return sum;
+}
+
+int instr(int a) {
+// CHECK: define {{.*}} i32 @instr(i32 %a) [[ATTR2:#[0-9]+]]
+ int sum = 0;
+ for (int i = 0; i < a; i++)
+ sum += g(i);
+ return sum;
+}
+// CHECK: attributes [[ATTR]] = {{.*}} noprofile
+// CHECK-NOT: attributes [[ATTR2]] = {{.*}} noprofile
Index: clang/lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.cpp
+++ clang/lib/CodeGen/CodeGenFunction.cpp
@@ -893,6 +893,9 @@
if (D && D->hasAttr<CFICanonicalJumpTableAttr>())
Fn->addFnAttr("cfi-canonical-jump-table");
+ if (D && D->hasAttr<NoInstrumentFunctionAttr>())
+ Fn->addFnAttr(llvm::Attribute::NoProfile);
+
if (getLangOpts().OpenCL) {
// Add metadata for a kernel function.
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
