On Wed, Sep 06, 2017 at 11:48:00AM -0500, Segher Boessenkool wrote:
> On Wed, Sep 06, 2017 at 06:26:10PM +0200, Jakub Jelinek wrote:
> > > Maybe this "switch to the other section" thing should be abstracted out?
> > > Messing with in_cold_section_p is a bit dirty.
> >
> > But it reflects the reality, and is what final.c and varasm.c also do.
>
> Yes, but those aren't target code :-)
>
> I'm suggesting adding a generic
> switch_from_hot_to_cold_or_the_other_way_around
> function (but with a better name ;-) ) that just does these same two lines,
> only not in target code. Seems cleaner to me, less surprising.
Richard, is this generic change ok?
2017-09-07 Jakub Jelinek <ja...@redhat.com>
PR target/81979
* output.h (switch_to_other_text_partition): New declaration.
* varasm.c (switch_to_other_text_partition): New function.
* config/rs6000/rs6000.c (uses_TOC): Return 2 if
NOTE_INSN_SWITCH_TEXT_SECTIONS is seen before finding load_toc_* insn.
(rs6000_elf_declare_function_name): If uses_TOC returned 2, switch
to the other text partition before emitting LCL label and switch back
after emitting the word after it.
* gcc.dg/pr81979.c: New test.
--- gcc/output.h.jj 2017-09-01 09:26:48.000000000 +0200
+++ gcc/output.h 2017-09-07 11:38:48.668090305 +0200
@@ -537,6 +537,7 @@ extern section *mergeable_constant_secti
extern section *function_section (tree);
extern section *unlikely_text_section (void);
extern section *current_function_section (void);
+extern void switch_to_other_text_partition (void);
/* Return the numbered .ctors.N (if CONSTRUCTOR_P) or .dtors.N (if
not) section for PRIORITY. */
--- gcc/varasm.c.jj 2017-09-06 11:09:39.000000000 +0200
+++ gcc/varasm.c 2017-09-07 11:35:34.366442544 +0200
@@ -695,6 +695,16 @@ unlikely_text_section_p (section *sect)
return sect == function_section_1 (current_function_decl, true);
}
+/* Switch to the other function partition (if inside of hot section
+ into cold section, otherwise into the hot section). */
+
+void
+switch_to_other_text_partition (void)
+{
+ in_cold_section_p = !in_cold_section_p;
+ switch_to_section (current_function_section ());
+}
+
/* Return the read-only data section associated with function DECL. */
section *
--- gcc/config/rs6000/rs6000.c.jj 2017-09-05 23:28:22.238928428 +0200
+++ gcc/config/rs6000/rs6000.c 2017-09-07 11:39:25.781640963 +0200
@@ -25324,32 +25324,41 @@ get_TOC_alias_set (void)
/* This returns nonzero if the current function uses the TOC. This is
determined by the presence of (use (unspec ... UNSPEC_TOC)), which
- is generated by the ABI_V4 load_toc_* patterns. */
+ is generated by the ABI_V4 load_toc_* patterns.
+ Return 2 instead of 1 if the load_toc_* pattern is in the function
+ partition that doesn't start the function. */
#if TARGET_ELF
static int
uses_TOC (void)
{
rtx_insn *insn;
+ int ret = 1;
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- {
- rtx pat = PATTERN (insn);
- int i;
+ {
+ if (INSN_P (insn))
+ {
+ rtx pat = PATTERN (insn);
+ int i;
- if (GET_CODE (pat) == PARALLEL)
- for (i = 0; i < XVECLEN (pat, 0); i++)
- {
- rtx sub = XVECEXP (pat, 0, i);
- if (GET_CODE (sub) == USE)
- {
- sub = XEXP (sub, 0);
- if (GET_CODE (sub) == UNSPEC
- && XINT (sub, 1) == UNSPEC_TOC)
- return 1;
- }
- }
- }
+ if (GET_CODE (pat) == PARALLEL)
+ for (i = 0; i < XVECLEN (pat, 0); i++)
+ {
+ rtx sub = XVECEXP (pat, 0, i);
+ if (GET_CODE (sub) == USE)
+ {
+ sub = XEXP (sub, 0);
+ if (GET_CODE (sub) == UNSPEC
+ && XINT (sub, 1) == UNSPEC_TOC)
+ return ret;
+ }
+ }
+ }
+ else if (crtl->has_bb_partition
+ && NOTE_P (insn)
+ && NOTE_KIND (insn) == NOTE_INSN_SWITCH_TEXT_SECTIONS)
+ ret = 2;
+ }
return 0;
}
#endif
@@ -33380,14 +33389,17 @@ rs6000_elf_declare_function_name (FILE *
return;
}
+ int uses_toc;
if (DEFAULT_ABI == ABI_V4
&& (TARGET_RELOCATABLE || flag_pic > 1)
&& !TARGET_SECURE_PLT
&& (!constant_pool_empty_p () || crtl->profile)
- && uses_TOC ())
+ && (uses_toc = uses_TOC ()))
{
char buf[256];
+ if (uses_toc == 2)
+ switch_to_other_text_partition ();
(*targetm.asm_out.internal_label) (file, "LCL", rs6000_pic_labelno);
fprintf (file, "\t.long ");
@@ -33397,6 +33409,8 @@ rs6000_elf_declare_function_name (FILE *
ASM_GENERATE_INTERNAL_LABEL (buf, "LCF", rs6000_pic_labelno);
assemble_name (file, buf);
putc ('\n', file);
+ if (uses_toc == 2)
+ switch_to_other_text_partition ();
}
ASM_OUTPUT_TYPE_DIRECTIVE (file, name, "function");
--- gcc/testsuite/gcc.dg/pr81979.c.jj 2017-09-07 11:31:15.893566211 +0200
+++ gcc/testsuite/gcc.dg/pr81979.c 2017-09-07 11:31:15.893566211 +0200
@@ -0,0 +1,32 @@
+/* PR target/81979 */
+/* { dg-do link } */
+/* { dg-options "-O2 -w" } */
+/* { dg-additional-options "-fPIC" { target fpic } } */
+/* { dg-additional-options "-freorder-blocks-and-partition" { target freorder
} } */
+
+int d;
+
+__attribute__((noinline, noclone)) void
+foo (int x)
+{
+ int c;
+ while (c < 1)
+ {
+ int o;
+ for (o = 0; o < 4; ++o)
+ c /= (x != 0) ? 2 : x;
+ }
+
+ d = 1;
+ for (;;)
+ ;
+}
+
+int
+main ()
+{
+ asm volatile ("" : : "r" (&d) : "memory");
+ foo (d);
+ asm volatile ("" : : "r" (&d) : "memory");
+ return 0;
+}
Jakub
