diff mbox

[RS6000] TARGET_RELOCATABLE

Message ID 20160504045118.GT18915@bubble.grove.modra.org
State New
Headers show

Commit Message

Alan Modra May 4, 2016, 4:51 a.m. UTC
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.

Bootstrapped and regression tested powerpc64-linux.  OK?

	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.

Comments

Segher Boessenkool May 4, 2016, 4:55 p.m. UTC | #1
On Wed, May 04, 2016 at 02:21:18PM +0930, Alan Modra wrote:
> 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).

That last one is even readable!  :-)

> 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.

Does this TARGET_NO_FP_IN_TOC setting need documenting somewhere?

> Bootstrapped and regression tested powerpc64-linux.  OK?

Okay for trunk, one nit...

> @@ -23868,7 +23869,9 @@ 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))

Superfluous parens on that last line.


Segher
Alan Modra May 4, 2016, 10:57 p.m. UTC | #2
On Wed, May 04, 2016 at 11:55:31AM -0500, Segher Boessenkool wrote:
> On Wed, May 04, 2016 at 02:21:18PM +0930, Alan Modra wrote:
> > 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.
> 
> Does this TARGET_NO_FP_IN_TOC setting need documenting somewhere?

It's not actually a change in behaviour.  We didn't put fp in toc
with -mrelocatable before this patch.
diff mbox

Patch

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 4bc7007..4a2aa00 100644
--- a/gcc/config/rs6000/predicates.md
+++ b/gcc/config/rs6000/predicates.md
@@ -539,13 +539,6 @@ 
   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 b443564..6fa8a0c 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -20677,7 +20677,8 @@  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)
@@ -23868,7 +23869,9 @@  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->lr_save_p = 1;
@@ -31322,8 +31325,7 @@  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)
+      && TARGET_MINIMAL_TOC)
     {
       if (!toc_initialized)
 	{
@@ -31344,8 +31346,7 @@  rs6000_elf_output_toc_section_asm_op (const void *data ATTRIBUTE_UNUSED)
       else
 	fprintf (asm_out_file, "%s\n", MINIMAL_TOC_SECTION_ASM_OP);
     }
-  else if ((DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_ELFv2)
-	   && !TARGET_RELOCATABLE)
+  else if (DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_ELFv2)
     {
       fprintf (asm_out_file, "%s\n", TOC_SECTION_ASM_OP);
       if (!toc_initialized)
@@ -31936,7 +31937,8 @@  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);
@@ -31966,7 +31968,8 @@  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);
@@ -32008,7 +32011,8 @@  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 12fa727..230ca43 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -636,18 +636,10 @@  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 576d26d..a6f219c 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -9499,12 +9499,8 @@ 
   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"