On 10/02/16 10:39, James Greenhalgh wrote:
On Wed, Feb 10, 2016 at 10:32:16AM +0000, Kyrill Tkachov wrote:
Hi James,
On 10/02/16 10:11, James Greenhalgh wrote:
On Thu, Feb 04, 2016 at 01:50:31PM +0000, Kyrill Tkachov wrote:
Hi all,
As part of the target attributes and pragmas support for GCC 6 I changed the
aarch64 port to emit a .arch assembly directive for each function that
describes the architectural features used by that function. This is a change
>from GCC 5 behaviour where we output a single .arch directive at the
beginning of the assembly file corresponding to architectural features given
on the command line.
<snip>
Bootstrapped and tested on aarch64-none-linux-gnu. With this patch I managed
to build a recent allyesconfig Linux kernel where before the build would fail
when assembling the LSE instructions.
Ok for trunk?
One comment, that I'm willing to be convinced on...
Thanks,
Kyrill
2016-02-04 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
* config/aarch64/aarch64.c (struct aarch64_output_asm_info):
New struct definition.
(aarch64_previous_asm_output): New variable.
(aarch64_declare_function_name): Only output .arch assembler
directive if it will be different from the previously output
directive.
(aarch64_start_file): New function.
(TARGET_ASM_FILE_START): Define.
2016-02-04 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
* gcc.target/aarch64/assembler_arch_1.c: Add -dA to dg-options.
Delete unneeded -save-temps.
* gcc.target/aarch64/assembler_arch_7.c: Likewise.
* gcc.target/aarch64/target_attr_15.c: Scan assembly for
.arch armv8-a\n.
* gcc.target/aarch64/assembler_arch_1.c: New test.
commit 2df0f24332e316b8d18d4571438f76726a0326e7
Author: Kyrylo Tkachov <kyrylo.tkac...@arm.com>
Date: Wed Jan 27 12:54:54 2016 +0000
[AArch64] Only update assembler .arch directive when necessary
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 5ca2ae8..0751440 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -11163,6 +11163,17 @@ aarch64_asm_preferred_eh_data_format (int code
ATTRIBUTE_UNUSED, int global)
return (global ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | type;
}
+struct aarch64_output_asm_info
+{
+ const struct processor *arch;
+ const struct processor *cpu;
+ unsigned long isa_flags;
Why not just keep the last string you printed, and use a string compare
to decide whether to print or not? Sure we'll end up doing a bit more
work, but the logic becomes simpler to follow and we don't need to pass
around another struct...
I did do it this way to avoid a string comparison (I try to avoid
manual string manipulations where I can as they're so easy to get wrong)
though this isn't on any hot path.
We don't really pass the structure around anywhere, we just keep one
instance. We'd have to do the same with a string i.e. keep a string
object around that we'd strcpy (or C++ equivalent) a string to every time
we wanted to update it, so I thought this approach is cleaner as the
architecture features are already fully described by a pointer to
an element in the static constant all_architectures table and an
unsigned long holding the ISA flags.
If you insist I can change it to a string, but I personally don't
think it's worth it.
Had you been working on a C string I probably wouldn't have noticed. But
you're already working with C++ strings in this function, so much of what
you are concerned about is straightforward.
I'd encourage you to try it using idiomatic string manipulation in C++, the
cleanup should be worth it.
Ok, here it is using std::string.
It is a shorter patch.
Bootstrapped and tested on aarch64.
Ok?
Thanks,
Kyrill
2016-02-10 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
* config/aarch64/aarch64.c (aarch64_last_printed_arch_string):
New variable.
(aarch64_last_printed_tune_string): Likewise.
(aarch64_declare_function_name): Only output .arch assembler
directive if it will be different from the previously output
directive. Same for .tune comment but only if -dA is set.
(aarch64_start_file): New function.
(TARGET_ASM_FILE_START): Define.
2016-02-10 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
* gcc.target/aarch64/target_attr_15.c: Scan assembly for
.arch armv8-a\n. Add -dA to dg-options.
* gcc.target/aarch64/assembler_arch_1.c: New test.
* gcc.target/aarch64/target_attr_7.c: Add -dA to dg-options.
Thanks,
James
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 59cbf81474ccdf34e59a4719ee88251bc658ef04..9055229cb31d1b6edad64efb96856610c1277161 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -11198,6 +11198,10 @@ aarch64_asm_preferred_eh_data_format (int code ATTRIBUTE_UNUSED, int global)
return (global ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | type;
}
+/* The last .arch and .tune assembly strings that we printed. */
+static std::string aarch64_last_printed_arch_string;
+static std::string aarch64_last_printed_tune_string;
+
/* Implement ASM_DECLARE_FUNCTION_NAME. Output the ISA features used
by the function fndecl. */
@@ -11220,23 +11224,55 @@ aarch64_declare_function_name (FILE *stream, const char* name,
unsigned long isa_flags = targ_options->x_aarch64_isa_flags;
std::string extension
= aarch64_get_extension_string_for_isa_flags (isa_flags);
- asm_fprintf (asm_out_file, "\t.arch %s%s\n",
- this_arch->name, extension.c_str ());
+ /* Only update the assembler .arch string if it is distinct from the last
+ such string we printed. */
+ std::string to_print = this_arch->name + extension;
+ if (to_print != aarch64_last_printed_arch_string)
+ {
+ asm_fprintf (asm_out_file, "\t.arch %s\n", to_print.c_str ());
+ aarch64_last_printed_arch_string = to_print;
+ }
/* Print the cpu name we're tuning for in the comments, might be
- useful to readers of the generated asm. */
-
+ useful to readers of the generated asm. Do it only when it changes
+ from function to function and verbose assembly is requested. */
const struct processor *this_tune
= aarch64_get_tune_cpu (targ_options->x_explicit_tune_core);
- asm_fprintf (asm_out_file, "\t" ASM_COMMENT_START ".tune %s\n",
- this_tune->name);
+ if (flag_debug_asm && aarch64_last_printed_tune_string != this_tune->name)
+ {
+ asm_fprintf (asm_out_file, "\t" ASM_COMMENT_START ".tune %s\n",
+ this_tune->name);
+ aarch64_last_printed_tune_string = this_tune->name;
+ }
/* Don't forget the type directive for ELF. */
ASM_OUTPUT_TYPE_DIRECTIVE (stream, name, "function");
ASM_OUTPUT_LABEL (stream, name);
}
+/* Implements TARGET_ASM_FILE_START. Output the assembly header. */
+
+static void
+aarch64_start_file (void)
+{
+ struct cl_target_option *default_options
+ = TREE_TARGET_OPTION (target_option_default_node);
+
+ const struct processor *default_arch
+ = aarch64_get_arch (default_options->x_explicit_arch);
+ unsigned long default_isa_flags = default_options->x_aarch64_isa_flags;
+ std::string extension
+ = aarch64_get_extension_string_for_isa_flags (default_isa_flags);
+
+ aarch64_last_printed_arch_string = default_arch->name + extension;
+ aarch64_last_printed_tune_string = "";
+ asm_fprintf (asm_out_file, "\t.arch %s\n",
+ aarch64_last_printed_arch_string.c_str ());
+
+ default_file_start ();
+}
+
/* Emit load exclusive. */
static void
@@ -13970,6 +14006,9 @@ aarch64_optab_supported_p (int op, machine_mode, machine_mode,
#define TARGET_ASM_CAN_OUTPUT_MI_THUNK \
hook_bool_const_tree_hwi_hwi_const_tree_true
+#undef TARGET_ASM_FILE_START
+#define TARGET_ASM_FILE_START aarch64_start_file
+
#undef TARGET_ASM_OUTPUT_MI_THUNK
#define TARGET_ASM_OUTPUT_MI_THUNK aarch64_output_mi_thunk
diff --git a/gcc/testsuite/gcc.target/aarch64/assembler_arch_1.c b/gcc/testsuite/gcc.target/aarch64/assembler_arch_1.c
new file mode 100644
index 0000000000000000000000000000000000000000..901e50a178d7a4a443a5ad0abe63f624688db268
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/assembler_arch_1.c
@@ -0,0 +1,20 @@
+/* { dg-do assemble } */
+/* { dg-options "-march=armv8-a" } */
+
+/* Make sure that the function header in assembly doesn't override
+ user asm arch_extension directives. */
+
+__asm__ (".arch_extension lse");
+
+void
+foo (int i, int *v)
+{
+ register int w0 asm ("w0") = i;
+ register int *x1 asm ("x1") = v;
+
+ asm volatile (
+ "\tstset %w[i], %[v]\n"
+ : [i] "+r" (w0), [v] "+Q" (v)
+ : "r" (x1)
+ : "x30");
+}
diff --git a/gcc/testsuite/gcc.target/aarch64/target_attr_1.c b/gcc/testsuite/gcc.target/aarch64/target_attr_1.c
index 852ce1e9f06fe6e9d95f88a036d9012c4aed1c10..0527d0c3d613ca696f63161e54d46cc0060b30fb 100644
--- a/gcc/testsuite/gcc.target/aarch64/target_attr_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/target_attr_1.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -mcpu=thunderx -save-temps" } */
+/* { dg-options "-O2 -mcpu=thunderx -dA" } */
/* Test that cpu attribute overrides the command-line -mcpu. */
diff --git a/gcc/testsuite/gcc.target/aarch64/target_attr_15.c b/gcc/testsuite/gcc.target/aarch64/target_attr_15.c
index 02091c6c542b98b61156409b437d142169348138..f72bec878bf635429d67d441f0ec168839ff9888 100644
--- a/gcc/testsuite/gcc.target/aarch64/target_attr_15.c
+++ b/gcc/testsuite/gcc.target/aarch64/target_attr_15.c
@@ -10,6 +10,4 @@ foo (int a)
return a + 1;
}
-/* { dg-final { scan-assembler-not "\\+fp" } } */
-/* { dg-final { scan-assembler-not "\\+crypto" } } */
-/* { dg-final { scan-assembler-not "\\+simd" } } */
+/* { dg-final { scan-assembler-times "\\.arch armv8-a\n" 1 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/target_attr_7.c b/gcc/testsuite/gcc.target/aarch64/target_attr_7.c
index 32a840378ab4cad8cc90b896be112c7c46bc01a8..818d327705f3d5ec7863da93c4181cc1441f58f5 100644
--- a/gcc/testsuite/gcc.target/aarch64/target_attr_7.c
+++ b/gcc/testsuite/gcc.target/aarch64/target_attr_7.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -mcpu=thunderx -save-temps" } */
+/* { dg-options "-O2 -mcpu=thunderx -dA" } */
/* Make sure that #pragma overrides command line option and
target attribute overrides the pragma. */
