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Re: [RS6000] ABI_V4 init of toc section
- From: Alan Modra <amodra at gmail dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: David Edelsohn <dje dot gcc at gmail dot com>
- Date: Mon, 1 Feb 2016 11:08:43 +1030
- Subject: Re: [RS6000] ABI_V4 init of toc section
- Authentication-results: sourceware.org; auth=none
- References: <20160129163824 dot GQ17028 at bubble dot grove dot modra dot org> <CAGWvny=L9cbE9kNRCUY=ioztvE2V4sH3WAPP8xJikNef8FFhwQ at mail dot gmail dot com> <20160130094408 dot GR17028 at bubble dot grove dot modra dot org>
This is the more comprehensive fix for PR68662, the one I'm a little
nervous about applying during stage4. OK for when stage1 opens?
Applying this patch makes
https://gcc.gnu.org/ml/gcc-patches/2016-01/msg02325.html redundant,
but I'm inclined to leave it in: Not initializing the toc symbol at
file start results in smaller assembly and object files when the TOC
is not used.
=================
For ABI_V4, -mrelocatable and -fPIC both generate position independent
code, with some extra "fixup" output for -mrelocatable. The
similarity of these two options has led to the situation where the
sysv4.h SUBTARGET_OVERRIDE_OPTIONS sets flag_pic on seeing
-mrelocatable, and sets TARGET_RELOCATABLE on seeing -fPIC. That
prevents LTO from properly optimizing position dependent executables,
because the mutual dependence of the flags and the fact that LTO
streaming records the state of rs6000_isa_flags, result in flag_pic
being set when it shouldn't be.
So, don't set TARGET_RELOCATABLE when -fPIC. Places that currently
test TARGET_RELOCATABLE can instead test
TARGET_RELOCATABLE || (DEFAULT_ABI == ABI_V4 && flag_pic > 1)
or since TARGET_RELOCATABLE can only be enabled when ABI_V4,
DEFAULT_ABI == ABI_V4 && (TARGET_RELOCATABLE || flag_pic > 1).
Also, since flag_pic is set by -mrelocatable, a number of places that
currently test TARGET_RELOCATABLE can be simplified. I also made
-mrelocatable set TARGET_NO_FP_IN_TOC, allowing TARGET_RELOCATABLE to
be removed from ASM_OUTPUT_SPECIAL_POOL_ENTRY_P. Reducing occurrences
of TARGET_RELOCATABLE is a good thing.
PR target/68662
* config/rs6000/sysv4.h (SUBTARGET_OVERRIDE_OPTIONS): Don't
set OPTION_MASK_RELOCATABLE when flag_pic == 2. Set
TARGET_NO_FP_IN_TOC for -mrelocatable.
(MINIMAL_TOC_SECTION_ASM_OP): Remove redundant
TARGET_RELOCATABLE test.
(ASM_OUTPUT_SPECIAL_POOL_ENTRY_P): Likewise.
(ASM_PREFERRED_EH_DATA_FORMAT): Likewise.
* config/rs6000/linux64.h (MINIMAL_TOC_SECTION_ASM_OP): Likewise.
(ASM_OUTPUT_SPECIAL_POOL_ENTRY_P): Likewise.
(ASM_PREFERRED_EH_DATA_FORMAT): Likewise.
* config/rs6000/freebsd64.h (MINIMAL_TOC_SECTION_ASM_OP): Likewise.
(ASM_OUTPUT_SPECIAL_POOL_ENTRY_P): Likewise.
(ASM_PREFERRED_EH_DATA_FORMAT): Likewise.
* config/rs6000/predicates.md (easy_fp_constant): Likewise.
* config/rs6000/rs6000.c (rs6000_elf_output_toc_section_asm_op):
Likewise.
(rs6000_assemble_integer): Update TARGET_RELOCATABLE test.
(rs6000_stack_info): Likewise.
(rs6000_elf_asm_out_constructor): Likewise.
(rs6000_elf_asm_out_destructor): Likewise.
(rs6000_elf_declare_function_name): Likewise.
* config/rs6000/rs6000.md (load_toc_aix_di): Likewise.
* config/rs6000/rs6000.h (MASK_RELOCATABLE, MASK_MINIMAL_TOC):
Don't define.
diff --git a/gcc/config/rs6000/freebsd64.h b/gcc/config/rs6000/freebsd64.h
index 899b858..3038c43 100644
--- a/gcc/config/rs6000/freebsd64.h
+++ b/gcc/config/rs6000/freebsd64.h
@@ -349,7 +349,7 @@ extern int dot_symbols;
true if the symbol may be affected by dynamic relocations. */
#undef ASM_PREFERRED_EH_DATA_FORMAT
#define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
- ((TARGET_64BIT || flag_pic || TARGET_RELOCATABLE) \
+ (TARGET_64BIT || flag_pic \
? (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel \
| (TARGET_64BIT ? DW_EH_PE_udata8 : DW_EH_PE_sdata4)) \
: DW_EH_PE_absptr)
@@ -384,7 +384,7 @@ extern int dot_symbols;
#define MINIMAL_TOC_SECTION_ASM_OP \
(TARGET_64BIT \
? "\t.section\t\".toc1\",\"aw\"" \
- : ((TARGET_RELOCATABLE || flag_pic) \
+ : (flag_pic \
? "\t.section\t\".got2\",\"aw\"" \
: "\t.section\t\".got1\",\"aw\""))
@@ -422,7 +422,6 @@ extern int dot_symbols;
&& ! TARGET_NO_FP_IN_TOC))) \
|| (!TARGET_64BIT \
&& !TARGET_NO_FP_IN_TOC \
- && !TARGET_RELOCATABLE \
&& SCALAR_FLOAT_MODE_P (GET_MODE (X)) \
&& BITS_PER_WORD == HOST_BITS_PER_INT)))))
diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index fefa0c4..e86b5d5 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -489,7 +489,7 @@ extern int dot_symbols;
#define MINIMAL_TOC_SECTION_ASM_OP \
(TARGET_64BIT \
? "\t.section\t\".toc1\",\"aw\"" \
- : ((TARGET_RELOCATABLE || flag_pic) \
+ : (flag_pic \
? "\t.section\t\".got2\",\"aw\"" \
: "\t.section\t\".got1\",\"aw\""))
@@ -585,7 +585,6 @@ extern int dot_symbols;
&& ! TARGET_NO_FP_IN_TOC))) \
|| (!TARGET_64BIT \
&& !TARGET_NO_FP_IN_TOC \
- && !TARGET_RELOCATABLE \
&& SCALAR_FLOAT_MODE_P (GET_MODE (X)) \
&& BITS_PER_WORD == HOST_BITS_PER_INT)))))
@@ -594,7 +593,7 @@ extern int dot_symbols;
true if the symbol may be affected by dynamic relocations. */
#undef ASM_PREFERRED_EH_DATA_FORMAT
#define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
- ((TARGET_64BIT || flag_pic || TARGET_RELOCATABLE) \
+ (TARGET_64BIT || flag_pic \
? (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel \
| (TARGET_64BIT ? DW_EH_PE_udata8 : DW_EH_PE_sdata4)) \
: DW_EH_PE_absptr)
diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md
index 302303c..ef104d5 100644
--- a/gcc/config/rs6000/predicates.md
+++ b/gcc/config/rs6000/predicates.md
@@ -538,13 +538,6 @@
if (flag_pic && DEFAULT_ABI == ABI_V4)
return 0;
-#ifdef TARGET_RELOCATABLE
- /* Similarly if we are using -mrelocatable, consider all constants
- to be hard. */
- if (TARGET_RELOCATABLE)
- return 0;
-#endif
-
/* If we have real FPRs, consider floating point constants hard (other than
0.0 under VSX), so that the constant gets pushed to memory during the
early RTL phases. This has the advantage that double precision constants
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 4ea4efb..1befd58 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -20404,7 +20404,8 @@ rs6000_assemble_integer (rtx x, unsigned int size, int aligned_p)
don't need to mark it here. We used to skip the text section, but it
should never be valid for relocated addresses to be placed in the text
section. */
- if (TARGET_RELOCATABLE
+ if (DEFAULT_ABI == ABI_V4
+ && (TARGET_RELOCATABLE || flag_pic > 1)
&& in_section != toc_section
&& !recurse
&& !CONST_SCALAR_INT_P (x)
@@ -23599,7 +23600,9 @@ rs6000_stack_info (void)
&& !TARGET_PROFILE_KERNEL)
|| (DEFAULT_ABI == ABI_V4 && cfun->calls_alloca)
#ifdef TARGET_RELOCATABLE
- || (TARGET_RELOCATABLE && (get_pool_size () != 0))
+ || (DEFAULT_ABI == ABI_V4
+ && (TARGET_RELOCATABLE || flag_pic > 1)
+ && (get_pool_size () != 0))
#endif
|| rs6000_ra_ever_killed ())
info_ptr->lr_save_p = 1;
@@ -31067,30 +31070,30 @@ rs6000_ms_bitfield_layout_p (const_tree record_type)
static void
rs6000_elf_output_toc_section_asm_op (const void *data ATTRIBUTE_UNUSED)
{
- if ((DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_ELFv2)
- && TARGET_MINIMAL_TOC
- && !TARGET_RELOCATABLE)
+ if (DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_ELFv2)
{
- if (!toc_initialized)
+ if (TARGET_MINIMAL_TOC)
{
- toc_initialized = 1;
- fprintf (asm_out_file, "%s\n", TOC_SECTION_ASM_OP);
- (*targetm.asm_out.internal_label) (asm_out_file, "LCTOC", 0);
- fprintf (asm_out_file, "\t.tc ");
- ASM_OUTPUT_INTERNAL_LABEL_PREFIX (asm_out_file, "LCTOC1[TC],");
- ASM_OUTPUT_INTERNAL_LABEL_PREFIX (asm_out_file, "LCTOC1");
- fprintf (asm_out_file, "\n");
-
- fprintf (asm_out_file, "%s\n", MINIMAL_TOC_SECTION_ASM_OP);
- ASM_OUTPUT_INTERNAL_LABEL_PREFIX (asm_out_file, "LCTOC1");
- fprintf (asm_out_file, " = .+32768\n");
+ if (!toc_initialized)
+ {
+ toc_initialized = 1;
+ fprintf (asm_out_file, "%s\n", TOC_SECTION_ASM_OP);
+ (*targetm.asm_out.internal_label) (asm_out_file, "LCTOC", 0);
+ fprintf (asm_out_file, "\t.tc ");
+ ASM_OUTPUT_INTERNAL_LABEL_PREFIX (asm_out_file, "LCTOC1[TC],");
+ ASM_OUTPUT_INTERNAL_LABEL_PREFIX (asm_out_file, "LCTOC1");
+ fprintf (asm_out_file, "\n");
+
+ fprintf (asm_out_file, "%s\n", MINIMAL_TOC_SECTION_ASM_OP);
+ ASM_OUTPUT_INTERNAL_LABEL_PREFIX (asm_out_file, "LCTOC1");
+ fprintf (asm_out_file, " = .+32768\n");
+ }
+ else
+ fprintf (asm_out_file, "%s\n", MINIMAL_TOC_SECTION_ASM_OP);
}
else
- fprintf (asm_out_file, "%s\n", MINIMAL_TOC_SECTION_ASM_OP);
+ fprintf (asm_out_file, "%s\n", TOC_SECTION_ASM_OP);
}
- else if ((DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_ELFv2)
- && !TARGET_RELOCATABLE)
- fprintf (asm_out_file, "%s\n", TOC_SECTION_ASM_OP);
else
{
fprintf (asm_out_file, "%s\n", MINIMAL_TOC_SECTION_ASM_OP);
@@ -31672,7 +31675,8 @@ rs6000_elf_asm_out_constructor (rtx symbol, int priority)
switch_to_section (get_section (section, SECTION_WRITE, NULL));
assemble_align (POINTER_SIZE);
- if (TARGET_RELOCATABLE)
+ if (DEFAULT_ABI == ABI_V4
+ && (TARGET_RELOCATABLE || flag_pic > 1))
{
fputs ("\t.long (", asm_out_file);
output_addr_const (asm_out_file, symbol);
@@ -31702,7 +31706,8 @@ rs6000_elf_asm_out_destructor (rtx symbol, int priority)
switch_to_section (get_section (section, SECTION_WRITE, NULL));
assemble_align (POINTER_SIZE);
- if (TARGET_RELOCATABLE)
+ if (DEFAULT_ABI == ABI_V4
+ && (TARGET_RELOCATABLE || flag_pic > 1))
{
fputs ("\t.long (", asm_out_file);
output_addr_const (asm_out_file, symbol);
@@ -31744,7 +31749,8 @@ rs6000_elf_declare_function_name (FILE *file, const char *name, tree decl)
return;
}
- if (TARGET_RELOCATABLE
+ if (DEFAULT_ABI == ABI_V4
+ && (TARGET_RELOCATABLE || flag_pic > 1)
&& !TARGET_SECURE_PLT
&& (get_pool_size () != 0 || crtl->profile)
&& uses_TOC ())
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index 8c6bd07..94606aa 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -635,18 +635,10 @@ extern int rs6000_vector_align[];
#define MASK_64BIT OPTION_MASK_64BIT
#endif
-#ifdef TARGET_RELOCATABLE
-#define MASK_RELOCATABLE OPTION_MASK_RELOCATABLE
-#endif
-
#ifdef TARGET_LITTLE_ENDIAN
#define MASK_LITTLE_ENDIAN OPTION_MASK_LITTLE_ENDIAN
#endif
-#ifdef TARGET_MINIMAL_TOC
-#define MASK_MINIMAL_TOC OPTION_MASK_MINIMAL_TOC
-#endif
-
#ifdef TARGET_REGNAMES
#define MASK_REGNAMES OPTION_MASK_REGNAMES
#endif
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index fe19853..563d92c 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -9496,12 +9496,8 @@
char buf[30];
extern int need_toc_init;
need_toc_init = 1;
-#ifdef TARGET_RELOCATABLE
ASM_GENERATE_INTERNAL_LABEL (buf, \"LCTOC\",
- !TARGET_MINIMAL_TOC || TARGET_RELOCATABLE);
-#else
- ASM_GENERATE_INTERNAL_LABEL (buf, \"LCTOC\", 1);
-#endif
+ !TARGET_ELF || !TARGET_MINIMAL_TOC);
if (TARGET_ELF)
strcat (buf, \"@toc\");
operands[1] = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (buf));
diff --git a/gcc/config/rs6000/sysv4.h b/gcc/config/rs6000/sysv4.h
index cbf9097..a4009c3 100644
--- a/gcc/config/rs6000/sysv4.h
+++ b/gcc/config/rs6000/sysv4.h
@@ -192,16 +192,25 @@ do { \
error ("-msecure-plt not supported by your assembler"); \
} \
\
- /* Treat -fPIC the same as -mrelocatable. */ \
if (flag_pic > 1 && DEFAULT_ABI == ABI_V4) \
{ \
- rs6000_isa_flags |= OPTION_MASK_RELOCATABLE | OPTION_MASK_MINIMAL_TOC; \
+ /* Note: flag_pic should not change any option flags that would \
+ be invalid with or pessimise -fno-PIC code. LTO turns off \
+ flag_pic when linking/recompiling a fixed position executable. \
+ However, if the objects were originally compiled with -fPIC, \
+ then other target options forced on here by -fPIC are restored \
+ when recompiling those objects without -fPIC. In particular \
+ TARGET_RELOCATABLE must not be enabled here by flag_pic. */ \
+ rs6000_isa_flags |= OPTION_MASK_MINIMAL_TOC; \
TARGET_NO_FP_IN_TOC = 1; \
} \
\
- else if (TARGET_RELOCATABLE) \
- if (!flag_pic) \
- flag_pic = 2; \
+ if (TARGET_RELOCATABLE) \
+ { \
+ if (!flag_pic) \
+ flag_pic = 2; \
+ TARGET_NO_FP_IN_TOC = 1; \
+ } \
} while (0)
#ifndef RS6000_BI_ARCH
@@ -317,8 +326,7 @@ do { \
/* Put PC relative got entries in .got2. */
#define MINIMAL_TOC_SECTION_ASM_OP \
- (TARGET_RELOCATABLE || (flag_pic && DEFAULT_ABI == ABI_V4) \
- ? "\t.section\t\".got2\",\"aw\"" : "\t.section\t\".got1\",\"aw\"")
+ (flag_pic ? "\t.section\t\".got2\",\"aw\"" : "\t.section\t\".got1\",\"aw\"")
#define SDATA_SECTION_ASM_OP "\t.section\t\".sdata\",\"aw\""
#define SDATA2_SECTION_ASM_OP "\t.section\t\".sdata2\",\"a\""
@@ -352,7 +360,6 @@ do { \
|| (GET_CODE (X) == CONST_INT \
&& GET_MODE_BITSIZE (MODE) <= GET_MODE_BITSIZE (Pmode)) \
|| (!TARGET_NO_FP_IN_TOC \
- && !TARGET_RELOCATABLE \
&& GET_CODE (X) == CONST_DOUBLE \
&& SCALAR_FLOAT_MODE_P (GET_MODE (X)) \
&& BITS_PER_WORD == HOST_BITS_PER_INT)))
@@ -941,9 +948,10 @@ ncrtn.o%s"
/* Select a format to encode pointers in exception handling data. CODE
is 0 for data, 1 for code labels, 2 for function pointers. GLOBAL is
true if the symbol may be affected by dynamic relocations. */
-#define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL) \
- ((flag_pic || TARGET_RELOCATABLE) \
- ? (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4) \
+#define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
+ (flag_pic \
+ ? (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel \
+ | DW_EH_PE_sdata4) \
: DW_EH_PE_absptr)
#define DOUBLE_INT_ASM_OP "\t.quad\t"
--
Alan Modra
Australia Development Lab, IBM