* [PATCH] rs6000: Entry point generation for functions using PC-relative addressing
@ 2019-05-22 23:40 Bill Schmidt
2019-05-23 11:06 ` Segher Boessenkool
0 siblings, 1 reply; 6+ messages in thread
From: Bill Schmidt @ 2019-05-22 23:40 UTC (permalink / raw)
To: GCC Patches; +Cc: Segher Boessenkool
Hi,
Functions using PC-relative addressing do not use a TOC, so there is no need for
a global entry point for TOC setup. Ensure we never generate a global entry
point, and use a .localentry directive that sets the upper st_other bits to 1.
Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no regressions.
Is this okay for trunk?
Thanks,
Bill
[gcc]
2019-05-22 Bill Schmidt <wschmidt@linux.ibm.com>
* config/rs6000/rs6000.c (rs6000_global_entry_point_needed_p):
Return false for PC-relative functions.
(rs6000_output_function_prologue): Emit ".localentry name,1" for
PC-relative functions.
[gcc/testsuite]
2019-05-22 Bill Schmidt <wschmidt@linux.ibm.com>
* gcc.target/powerpc/localentry-1.c: New file.
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 959e222c9cb..23c6d37ab55 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -26191,6 +26191,10 @@ rs6000_global_entry_point_needed_p (void)
if (TARGET_SINGLE_PIC_BASE)
return false;
+ /* PC-relative functions never generate a global entry point prologue. */
+ if (rs6000_pcrel_p (cfun))
+ return false;
+
/* Ensure we have a global entry point for thunks. ??? We could
avoid that if the target routine doesn't need a global entry point,
but we do not know whether this is the case at this point. */
@@ -27545,12 +27549,12 @@ rs6000_output_function_prologue (FILE *file)
#endif
}
+ const char *name = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
+
/* ELFv2 ABI r2 setup code and local entry point. This must follow
immediately after the global entry point label. */
if (rs6000_global_entry_point_needed_p ())
{
- const char *name = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
-
(*targetm.asm_out.internal_label) (file, "LCF", rs6000_pic_labelno);
if (TARGET_CMODEL != CMODEL_LARGE)
@@ -27601,6 +27605,18 @@ rs6000_output_function_prologue (FILE *file)
fputs ("\n", file);
}
+ else if (rs6000_pcrel_p (cfun))
+ {
+ /* All functions compiled to use PC-relative addressing will
+ have a .localentry value of 0 or 1. For now we set it to
+ 1 all the time, indicating that the function may clobber
+ the TOC register r2. Later we may optimize this by setting
+ it to 0 if the function is a leaf and does not clobber r2. */
+ fputs ("\t.localentry\t", file);
+ assemble_name (file, name);
+ fputs (",1\n", file);
+ }
+
/* Output -mprofile-kernel code. This needs to be done here instead of
in output_function_profile since it must go after the ELFv2 ABI
local entry point. */
diff --git a/gcc/testsuite/gcc.target/powerpc/localentry-1.c b/gcc/testsuite/gcc.target/powerpc/localentry-1.c
new file mode 100644
index 00000000000..15e00d9917e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/localentry-1.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-mcpu=future -O2" } */
+/* { dg-require-effective-target powerpc_elfv2 } */
+/* { dg-skip-if "do not override -mcpu" { powerpc*-*-* } { "-mcpu=*" } { "-mcpu=future" } } */
+
+/* Ensure we generate ".localentry fn,1" for both leaf and non-leaf
+ functions. */
+
+extern int y (int);
+
+int x (void)
+{
+ return y (5);
+}
+
+void z (void) { };
+
+/* { dg-final { scan-assembler {\.localentry\t\mx,1\M} } } */
+/* { dg-final { scan-assembler {\.localentry\t\mz,1\M} } } */
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] rs6000: Entry point generation for functions using PC-relative addressing
2019-05-22 23:40 [PATCH] rs6000: Entry point generation for functions using PC-relative addressing Bill Schmidt
@ 2019-05-23 11:06 ` Segher Boessenkool
2019-05-23 13:56 ` Bill Schmidt
2019-05-23 15:23 ` [PATCH v2] " Bill Schmidt
0 siblings, 2 replies; 6+ messages in thread
From: Segher Boessenkool @ 2019-05-23 11:06 UTC (permalink / raw)
To: Bill Schmidt; +Cc: GCC Patches
Hi!
On Wed, May 22, 2019 at 06:39:55PM -0500, Bill Schmidt wrote:
> @@ -26191,6 +26191,10 @@ rs6000_global_entry_point_needed_p (void)
> if (TARGET_SINGLE_PIC_BASE)
> return false;
>
> + /* PC-relative functions never generate a global entry point prologue. */
> + if (rs6000_pcrel_p (cfun))
> + return false;
"global_entry_point_needed" is such a confusing name; it isn't what this
function is about. "global entry point prologue" like in your comment
is much closer to the truth, but also not exactly it.
Maybe we should rename this function. And/or split it into two.
> + const char *name = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
This var is only used on some code paths. Factor this better, instead?
This ties in with the previous point.
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/localentry-1.c
> @@ -0,0 +1,19 @@
> +/* { dg-do compile } */
> +/* { dg-options "-mcpu=future -O2" } */
> +/* { dg-require-effective-target powerpc_elfv2 } */
> +/* { dg-skip-if "do not override -mcpu" { powerpc*-*-* } { "-mcpu=*" } { "-mcpu=future" } } */
Lose this last line, use -mdejagnu-cpu=future instead please.
Segher
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] rs6000: Entry point generation for functions using PC-relative addressing
2019-05-23 11:06 ` Segher Boessenkool
@ 2019-05-23 13:56 ` Bill Schmidt
2019-05-23 15:15 ` Segher Boessenkool
2019-05-23 15:23 ` [PATCH v2] " Bill Schmidt
1 sibling, 1 reply; 6+ messages in thread
From: Bill Schmidt @ 2019-05-23 13:56 UTC (permalink / raw)
To: Segher Boessenkool; +Cc: GCC Patches
On 5/23/19 6:06 AM, Segher Boessenkool wrote:
> Hi!
>
> On Wed, May 22, 2019 at 06:39:55PM -0500, Bill Schmidt wrote:
>> @@ -26191,6 +26191,10 @@ rs6000_global_entry_point_needed_p (void)
>> if (TARGET_SINGLE_PIC_BASE)
>> return false;
>>
>> + /* PC-relative functions never generate a global entry point prologue. */
>> + if (rs6000_pcrel_p (cfun))
>> + return false;
> "global_entry_point_needed" is such a confusing name; it isn't what this
> function is about. "global entry point prologue" like in your comment
> is much closer to the truth, but also not exactly it.
>
> Maybe we should rename this function. And/or split it into two.
I think "global entry point prologue" is exactly right, and the
function-level comment even says that. So we could change this to
rs6000_global_entry_point_prologue_needed_p. A bit chewy but digestible.
>
>> + const char *name = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
> This var is only used on some code paths. Factor this better, instead?
> This ties in with the previous point.
>
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/localentry-1.c
>> @@ -0,0 +1,19 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-mcpu=future -O2" } */
>> +/* { dg-require-effective-target powerpc_elfv2 } */
>> +/* { dg-skip-if "do not override -mcpu" { powerpc*-*-* } { "-mcpu=*" } { "-mcpu=future" } } */
> Lose this last line, use -mdejagnu-cpu=future instead please.
Yeah, sorry, original patch predated that change and I missed it again.
Thanks!
Bill
>
>
> Segher
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] rs6000: Entry point generation for functions using PC-relative addressing
2019-05-23 13:56 ` Bill Schmidt
@ 2019-05-23 15:15 ` Segher Boessenkool
0 siblings, 0 replies; 6+ messages in thread
From: Segher Boessenkool @ 2019-05-23 15:15 UTC (permalink / raw)
To: Bill Schmidt; +Cc: GCC Patches
On Thu, May 23, 2019 at 08:56:23AM -0500, Bill Schmidt wrote:
> On 5/23/19 6:06 AM, Segher Boessenkool wrote:
> > On Wed, May 22, 2019 at 06:39:55PM -0500, Bill Schmidt wrote:
> >> @@ -26191,6 +26191,10 @@ rs6000_global_entry_point_needed_p (void)
> >> if (TARGET_SINGLE_PIC_BASE)
> >> return false;
> >>
> >> + /* PC-relative functions never generate a global entry point prologue. */
> >> + if (rs6000_pcrel_p (cfun))
> >> + return false;
> > "global_entry_point_needed" is such a confusing name; it isn't what this
> > function is about. "global entry point prologue" like in your comment
> > is much closer to the truth, but also not exactly it.
> >
> > Maybe we should rename this function. And/or split it into two.
> I think "global entry point prologue" is exactly right, and the
> function-level comment even says that. So we could change this to
> rs6000_global_entry_point_prologue_needed_p. A bit chewy but digestible.
So I see the second use really needs the same condition... okay.
What it checks is if the function needs a local entry point not equal to
the global entry point.
Anyway... Not too important, the function isn't used in many places at all.
Segher
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2] rs6000: Entry point generation for functions using PC-relative addressing
2019-05-23 11:06 ` Segher Boessenkool
2019-05-23 13:56 ` Bill Schmidt
@ 2019-05-23 15:23 ` Bill Schmidt
2019-05-23 16:34 ` Segher Boessenkool
1 sibling, 1 reply; 6+ messages in thread
From: Bill Schmidt @ 2019-05-23 15:23 UTC (permalink / raw)
To: Segher Boessenkool; +Cc: GCC Patches
Hi,
Functions using PC-relative addressing do not use a TOC, so there is no need for
a global entry point for TOC setup. Ensure we never generate a global entry
point, and use a .localentry directive that sets the upper st_other bits to 1.
Also change a function name for clarity, and move a var decl off of paths
where it will not be executed, per previous comments by Segher.
Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no regressions.
Is this okay for trunk?
Thanks!
Bill
[gcc]
2019-05-23 Bill Schmidt <wschmidt@linux.ibm.com>
* config/rs6000/rs6000.c (rs6000_global_entry_point_needed_p):
Rename to rs6000_global_entry_point_prologue_needed_p. Return
false for PC-relative functions.
(rs6000_output_function_prologue): Change called function name to
rs6000_global_entry_point_prologue_needed_p. Emit ".localentry
name,1" for PC-relative functions.
(rs6000_elf_declare_function_name): Change called function name to
rs6000_global_entry_point_prologue_needed_p.
[gcc/testsuite]
2019-05-23 Bill Schmidt <wschmidt@linux.ibm.com>
* gcc.target/powerpc/localentry-1.c: New file.
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 7a2e43fd72a..3d5cf9e4ece 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -26180,7 +26180,7 @@ split_stack_arg_pointer_used_p (void)
/* Return whether we need to emit an ELFv2 global entry point prologue. */
static bool
-rs6000_global_entry_point_needed_p (void)
+rs6000_global_entry_point_prologue_needed_p (void)
{
/* Only needed for the ELFv2 ABI. */
if (DEFAULT_ABI != ABI_ELFv2)
@@ -26191,6 +26191,10 @@ rs6000_global_entry_point_needed_p (void)
if (TARGET_SINGLE_PIC_BASE)
return false;
+ /* PC-relative functions never generate a global entry point prologue. */
+ if (rs6000_pcrel_p (cfun))
+ return false;
+
/* Ensure we have a global entry point for thunks. ??? We could
avoid that if the target routine doesn't need a global entry point,
but we do not know whether this is the case at this point. */
@@ -27547,10 +27551,9 @@ rs6000_output_function_prologue (FILE *file)
/* ELFv2 ABI r2 setup code and local entry point. This must follow
immediately after the global entry point label. */
- if (rs6000_global_entry_point_needed_p ())
+ if (rs6000_global_entry_point_prologue_needed_p ())
{
const char *name = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
-
(*targetm.asm_out.internal_label) (file, "LCF", rs6000_pic_labelno);
if (TARGET_CMODEL != CMODEL_LARGE)
@@ -27601,6 +27604,19 @@ rs6000_output_function_prologue (FILE *file)
fputs ("\n", file);
}
+ else if (rs6000_pcrel_p (cfun))
+ {
+ const char *name = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
+ /* All functions compiled to use PC-relative addressing will
+ have a .localentry value of 0 or 1. For now we set it to
+ 1 all the time, indicating that the function may clobber
+ the TOC register r2. Later we may optimize this by setting
+ it to 0 if the function is a leaf and does not clobber r2. */
+ fputs ("\t.localentry\t", file);
+ assemble_name (file, name);
+ fputs (",1\n", file);
+ }
+
/* Output -mprofile-kernel code. This needs to be done here instead of
in output_function_profile since it must go after the ELFv2 ABI
local entry point. */
@@ -33335,7 +33351,8 @@ rs6000_elf_declare_function_name (FILE *file, const char *name, tree decl)
ASM_OUTPUT_TYPE_DIRECTIVE (file, name, "function");
ASM_DECLARE_RESULT (file, DECL_RESULT (decl));
- if (TARGET_CMODEL == CMODEL_LARGE && rs6000_global_entry_point_needed_p ())
+ if (TARGET_CMODEL == CMODEL_LARGE
+ && rs6000_global_entry_point_prologue_needed_p ())
{
char buf[256];
diff --git a/gcc/testsuite/gcc.target/powerpc/localentry-1.c b/gcc/testsuite/gcc.target/powerpc/localentry-1.c
new file mode 100644
index 00000000000..ce687a7f6ec
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/localentry-1.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-mdejagnu-cpu=future -O2" } */
+/* { dg-require-effective-target powerpc_elfv2 } */
+
+/* Ensure we generate ".localentry fn,1" for both leaf and non-leaf
+ functions. */
+
+extern int y (int);
+
+int x (void)
+{
+ return y (5);
+}
+
+void z (void) { };
+
+/* { dg-final { scan-assembler {\.localentry\t\mx,1\M} } } */
+/* { dg-final { scan-assembler {\.localentry\t\mz,1\M} } } */
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] rs6000: Entry point generation for functions using PC-relative addressing
2019-05-23 15:23 ` [PATCH v2] " Bill Schmidt
@ 2019-05-23 16:34 ` Segher Boessenkool
0 siblings, 0 replies; 6+ messages in thread
From: Segher Boessenkool @ 2019-05-23 16:34 UTC (permalink / raw)
To: Bill Schmidt; +Cc: GCC Patches
On Thu, May 23, 2019 at 10:21:44AM -0500, Bill Schmidt wrote:
> Functions using PC-relative addressing do not use a TOC, so there is no need for
> a global entry point for TOC setup. Ensure we never generate a global entry
> point, and use a .localentry directive that sets the upper st_other bits to 1.
> Also change a function name for clarity, and move a var decl off of paths
> where it will not be executed, per previous comments by Segher.
>
> Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no regressions.
> Is this okay for trunk?
Yes please. Thanks,
Segher
> 2019-05-23 Bill Schmidt <wschmidt@linux.ibm.com>
>
> * config/rs6000/rs6000.c (rs6000_global_entry_point_needed_p):
> Rename to rs6000_global_entry_point_prologue_needed_p. Return
> false for PC-relative functions.
> (rs6000_output_function_prologue): Change called function name to
> rs6000_global_entry_point_prologue_needed_p. Emit ".localentry
> name,1" for PC-relative functions.
> (rs6000_elf_declare_function_name): Change called function name to
> rs6000_global_entry_point_prologue_needed_p.
>
> [gcc/testsuite]
>
> 2019-05-23 Bill Schmidt <wschmidt@linux.ibm.com>
>
> * gcc.target/powerpc/localentry-1.c: New file.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2019-05-22 23:40 [PATCH] rs6000: Entry point generation for functions using PC-relative addressing Bill Schmidt
2019-05-23 11:06 ` Segher Boessenkool
2019-05-23 13:56 ` Bill Schmidt
2019-05-23 15:15 ` Segher Boessenkool
2019-05-23 15:23 ` [PATCH v2] " Bill Schmidt
2019-05-23 16:34 ` Segher Boessenkool
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