From: Andi Kleen <a...@linux.intel.com>
[This was an old patch of mine that has been posted before,
but never made it in]
This adds a new C/C++ option to force
__attribute__((no_instrument_function)) on every function compiled.
This is useful together with LTO. You may want to have the whole
program compiled with -pg and have to specify that in the LTO
link, but want to disable it for some specific files. As the
option works on the frontend level it is already passed through
properly by LTO.
Without LTO it is equivalent to not specifing -pg or -mfentry.
This fixes some missing functionality in the Linux kernel LTO port,
in particular it allows using the function tracer with LTO kernels.
Longer term it would be nicer if all suitable options were handled
like this for LTO by turning them into attributes, but that would
be a much larger project.
Passed bootstrap and test suite on x86_64-linux. Ok?
gcc/:
2014-09-01 Andi Kleen <a...@linux.intel.com>
* c.opt (fno-instrument-function): Document.
gcc/c:
2014-09-01 Andi Kleen <a...@linux.intel.com>
* c-decl.c (start_function): Handle force_no_instrument_function
gcc/cp:
2014-09-01 Andi Kleen <a...@linux.intel.com>
* decl.c (start_preparsed_function): Handle
force_no_instrument_function
gcc/testsuite:
2014-09-01 Andi Kleen <a...@linux.intel.com>
* g++.dg/fno-instrument-function.C: Add.
* gcc.dg/fno-instrument-function.c: Add.
---
gcc/c-family/c.opt | 4 ++++
gcc/c/c-decl.c | 3 +++
gcc/cp/decl.c | 3 +++
gcc/doc/invoke.texi | 8 +++++++-
gcc/testsuite/g++.dg/fno-instrument-function.C | 18 ++++++++++++++++++
gcc/testsuite/gcc.dg/fno-instrument-function.c | 24 ++++++++++++++++++++++++
6 files changed, 59 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/fno-instrument-function.C
create mode 100644 gcc/testsuite/gcc.dg/fno-instrument-function.c
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 210a099..2aabd23 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1118,6 +1118,10 @@ Enum(ivar_visibility) String(public)
Value(IVAR_VISIBILITY_PUBLIC)
EnumValue
Enum(ivar_visibility) String(package) Value(IVAR_VISIBILITY_PACKAGE)
+fno-instrument-function
+C C++ ObjC ObjC++ RejectNegative Report Var(force_no_instrument_function)
+Force __attribute__((no_instrument_function)) for all functions in translation
unit.
+
fnonansi-builtins
C++ ObjC++ Var(flag_no_nonansi_builtin, 0)
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index b4995a6..493240f 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -8044,6 +8044,9 @@ start_function (struct c_declspecs *declspecs, struct
c_declarator *declarator,
if (current_scope == file_scope)
maybe_apply_pragma_weak (decl1);
+ if (force_no_instrument_function)
+ DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl1) = 1;
+
/* Warn for unlikely, improbable, or stupid declarations of `main'. */
if (warn_main && MAIN_NAME_P (DECL_NAME (decl1)))
{
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index d03f8a4..505ad50 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -13251,6 +13251,9 @@ start_preparsed_function (tree decl1, tree attrs, int
flags)
&& lookup_attribute ("noinline", attrs))
warning (0, "inline function %q+D given attribute noinline", decl1);
+ if (force_no_instrument_function)
+ DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl1) = 1;
+
/* Handle gnu_inline attribute. */
if (GNU_INLINE_P (decl1))
{
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index d15d4a9..51b8d20 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -169,7 +169,7 @@ in the following sections.
-aux-info @var{filename} -fallow-parameterless-variadic-functions @gol
-fno-asm -fno-builtin -fno-builtin-@var{function} @gol
-fhosted -ffreestanding -fopenmp -fopenmp-simd -fms-extensions @gol
--fplan9-extensions -trigraphs -traditional -traditional-cpp @gol
+-fplan9-extensions -trigraphs -traditional -traditional-cpp
-fno-instrument-function @gol
-fallow-single-precision -fcond-mismatch -flax-vector-conversions @gol
-fsigned-bitfields -fsigned-char @gol
-funsigned-bitfields -funsigned-char}
@@ -1971,6 +1971,12 @@ Allow implicit conversions between vectors with
differing numbers of
elements and/or incompatible element types. This option should not be
used for new code.
+@item -fno-instrument-function
+@opindex fno-instrument-function
+Override @option{-pg} for this translation unit. This is useful with
+Link Time Optimization (LTO) to override the effects of -pg for a
+specific source file.
+
@item -funsigned-char
@opindex funsigned-char
Let the type @code{char} be unsigned, like @code{unsigned char}.
diff --git a/gcc/testsuite/g++.dg/fno-instrument-function.C
b/gcc/testsuite/g++.dg/fno-instrument-function.C
new file mode 100644
index 0000000..e2f6518
--- /dev/null
+++ b/gcc/testsuite/g++.dg/fno-instrument-function.C
@@ -0,0 +1,18 @@
+/* Test -fno-instrument-function */
+/* { dg-do compile } */
+/* { dg-options "-pg -fno-instrument-function" } */
+/* { dg-final { scan-assembler-not "mcount" } } */
+/* Origin: Andi Kleen */
+extern void foobar(const char *);
+
+void func(void)
+{
+ foobar ("Hello world\n");
+}
+
+void func2(void)
+{
+ int i;
+ for (i = 0; i < 10; i++)
+ foobar ("Hello world");
+}
diff --git a/gcc/testsuite/gcc.dg/fno-instrument-function.c
b/gcc/testsuite/gcc.dg/fno-instrument-function.c
new file mode 100644
index 0000000..9c68fa8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fno-instrument-function.c
@@ -0,0 +1,24 @@
+/* Test -fno-instrument-function */
+/* { dg-do compile } */
+/* { dg-options "-pg -fno-instrument-function" } */
+/* { dg-final { scan-assembler-not "mcount" } } */
+/* Origin: Andi Kleen */
+extern void foobar(char *);
+
+void func(void)
+{
+ foobar ("Hello world\n");
+}
+
+void func2(void)
+{
+ int i;
+ for (i = 0; i < 10; i++)
+ foobar ("Hello world");
+}
+
+void func3(a)
+char *a;
+{
+ foobar("Hello world");
+}
--
2.1.0
