mips.h (MASK_UNUSED1): Remove.

	* config/mips/mips.h (MASK_UNUSED1): Remove.
	(MASK_XGOT, TARGET_XGOT): Define.
	(TARGET_SWITCHES): Add an entry for -mxgot.
	(ASM_SPEC): Map -mxgot to -xgot.
	* config/mips/mips.c (mips_symbol_insns): Use TARGET_XGOT to decide
	whether we're using a big-GOT sequences.
	(mips_legitimize_const_move, mips_expand_call): Likewise.
	(override_options): Revert 2003-01-09 change.
	* doc/invoke.texi: Document -mxgot.

From-SVN: r71018

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4079acc..bbefe0b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2003-09-03  Richard Sandiford  <rsandifo@redhat.com>
+
+       * config/mips/mips.h (MASK_UNUSED1): Remove.
+       (MASK_XGOT, TARGET_XGOT): Define.
+       (TARGET_SWITCHES): Add an entry for -mxgot.
+       (ASM_SPEC): Map -mxgot to -xgot.
+       * config/mips/mips.c (mips_symbol_insns): Use TARGET_XGOT to decide
+       whether we're using a big-GOT sequences.
+       (mips_legitimize_const_move, mips_expand_call): Likewise.
+       (override_options): Revert 2003-01-09 change.
+       * doc/invoke.texi: Document -mxgot.
+
 2003-09-02  Jason Merrill  <jason@redhat.com>
 
        * config/sol2.h (NO_IMPLICIT_EXTERN_C): Define here.

diff --git a/gcc/config/mips/mips.c b/gcc/config/mips/mips.c
index 37fd534..7453924 100644 (file)
--- a/gcc/config/mips/mips.c
+++ b/gcc/config/mips/mips.c
@@ -1081,7 +1081,7 @@ mips_symbol_insns (enum mips_symbol_type type)
              daddu   $at,$at,$gp
 
         and the final address is $at + %got_lo(symbol).  */
-      return (flag_pic == 1 ? 1 : 3);
+      return (TARGET_XGOT ? 3 : 1);
 
     case SYMBOL_GOT_LOCAL:
       /* For o32 and o64, the sequence is:
@@ -1881,10 +1881,10 @@ mips_legitimize_const_move (enum machine_mode mode, rtx dest, rtx src)
       && GET_CODE (src) == SYMBOL_REF
       && mips_classify_symbol (src) == SYMBOL_GOT_GLOBAL)
     {
-      if (flag_pic == 1)
-       src = mips_load_got16 (src, RELOC_GOT_DISP);
-      else
+      if (TARGET_XGOT)
        src = mips_load_got32 (temp, src, RELOC_GOT_HI, RELOC_GOT_LO);
+      else
+       src = mips_load_got16 (src, RELOC_GOT_DISP);
       emit_insn (gen_rtx_SET (VOIDmode, dest, src));
       return;
     }
@@ -3213,10 +3213,10 @@ mips_expand_call (rtx result, rtx addr, rtx args_size, rtx aux, int sibcall_p)
          && GET_CODE (addr) == SYMBOL_REF
          && mips_classify_symbol (addr) == SYMBOL_GOT_GLOBAL)
        {
-         if (flag_pic == 1)
-           addr = mips_load_got16 (addr, RELOC_CALL16);
-         else
+         if (TARGET_XGOT)
            addr = mips_load_got32 (0, addr, RELOC_CALL_HI, RELOC_CALL_LO);
+         else
+           addr = mips_load_got16 (addr, RELOC_CALL16);
        }
       addr = force_reg (Pmode, addr);
     }
@@ -4632,8 +4632,7 @@ override_options (void)
      implemented.  */
   if (TARGET_ABICALLS)
     {
-      if (flag_pic == 0)
-       flag_pic = 1;
+      flag_pic = 1;
       if (mips_section_threshold > 0)
        warning ("-G is incompatible with PIC code which is the default");
     }

diff --git a/gcc/config/mips/mips.h b/gcc/config/mips/mips.h
index 949fc74..716c277 100644 (file)
--- a/gcc/config/mips/mips.h
+++ b/gcc/config/mips/mips.h
@@ -153,7 +153,7 @@ extern const struct mips_cpu_info *mips_tune_info;
 #define MASK_SOFT_FLOAT           0x00000100   /* software floating point */
 #define MASK_FLOAT64      0x00000200   /* fp registers are 64 bits */
 #define MASK_ABICALLS     0x00000400   /* emit .abicalls/.cprestore/.cpload */
-#define MASK_UNUSED1      0x00000800   /* Unused Mask.  */
+#define MASK_XGOT         0x00000800   /* emit big-got PIC */
 #define MASK_LONG_CALLS           0x00001000   /* Always call through a register */
 #define MASK_64BIT        0x00002000   /* Use 64 bit GP registers and insns */
 #define MASK_EMBEDDED_PIC  0x00004000  /* Generate embedded PIC code */
@@ -218,6 +218,7 @@ extern const struct mips_cpu_info *mips_tune_info;
 
                                        /* .abicalls, etc from Pyramid V.4 */
 #define TARGET_ABICALLS                (target_flags & MASK_ABICALLS)
+#define TARGET_XGOT            (target_flags & MASK_XGOT)
 
                                        /* software floating point */
 #define TARGET_SOFT_FLOAT      (target_flags & MASK_SOFT_FLOAT)
@@ -602,6 +603,10 @@ extern const struct mips_cpu_info *mips_tune_info;
      N_("Generate mips16 code") },                                     \
   {"no-mips16",                 -MASK_MIPS16,                                  \
      N_("Generate normal-mode code") },                                        \
+  {"xgot",               MASK_XGOT,                                    \
+     N_("Lift restrictions on GOT size") },                            \
+  {"no-xgot",           -MASK_XGOT,                                    \
+     N_("Do not lift restrictions on GOT size") },                     \
   {"debug",              MASK_DEBUG,                                   \
      NULL},                                                            \
   {"debuga",             MASK_DEBUG_A,                                 \
@@ -1082,7 +1087,7 @@ extern const struct mips_cpu_info *mips_tune_info;
 %{membedded-pic} \
 %{mabi=32:-32}%{mabi=n32:-n32}%{mabi=64:-64}%{mabi=n64:-64} \
 %{mabi=eabi} %{mabi=o64} %{!mabi*: %(asm_abi_default_spec)} \
-%{mgp32} %{mgp64} %{march=*} \
+%{mgp32} %{mgp64} %{march=*} %{mxgot:-xgot} \
 %(target_asm_spec) \
 %(subtarget_asm_spec)"
 

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index d68eb0e..fb4cf78 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -471,7 +471,7 @@ in the following sections.
 -mgas  -mgp32  -mgp64  -mhard-float  -mint64  -mips1 @gol
 -mips2  -mips3  -mips4  -mips32  -mips32r2  -mips64 @gol
 -mlong64  -mlong32  -mlong-calls  -mmemcpy @gol
--mmips-as  -mmips-tfile  -mno-abicalls @gol
+-mmips-as  -mmips-tfile  -mno-abicalls  -mxgot @gol
 -mno-embedded-data  -mno-uninit-const-in-rodata @gol
 -mno-embedded-pic  -mno-long-calls @gol
 -mno-memcpy  -mno-mips-tfile  -mno-rnames @gol
@@ -8067,6 +8067,35 @@ Emit (or do not emit) the pseudo operations @samp{.abicalls},
 @samp{.cpload}, and @samp{.cprestore} that some System V.4 ports use for
 position independent code.
 
+@item -mxgot
+@itemx -mno-xgot
+@opindex mxgot
+@opindex mno-xgot
+Lift (or do not lift) the usual restrictions on the size of the global
+offset table.
+
+GCC normally uses a single instruction to load values from the GOT.
+While this is relatively efficient, it will only work if the GOT
+is smaller than about 64k.  Anything larger will cause the linker
+to report an error such as:
+
+@cindex relocation truncated to fit (MIPS)
+@smallexample
+relocation truncated to fit: R_MIPS_GOT16 foobar
+@end smallexample
+
+If this happens, you should recompile your code with @option{-mxgot}.
+It should then work with very large GOTs, although it will also be
+less efficient, since it will take three instructions to fetch the
+value of a global symbol.
+
+Note that some linkers can create multiple GOTs.  If you have such a
+linker, you should only need to use @option{-mxgot} when a single object
+file accesses more than 64k's worth of GOT entries.  Very few do.
+
+These options have no effect unless GCC is generating position
+independent code.
+
 @item -mlong-calls
 @itemx -mno-long-calls
 @opindex mlong-calls