Richard Henderson <r...@redhat.com> writes:
> On 02/04/2012 02:06 AM, Richard Sandiford wrote:
>>> > Actually I had that idea of a link-once function too, but it turned out
>>> > quite complicated to do without rewriting some generic parts of GCC as it
>>> > is currently not prepared to emit link-once functions outside C++
>>> > compilations. It's been a while and I did lots of other stuff meanwhile,
>>> > so please excuse me if I got anything wrong here.
>> Hmm, OK, I wouldn't have expected that. But if you've tried making
>> __mips16_rdhwr link-once and had a bad experience with it, then yeah,
>> let's go with the hidden libgcc function. It's just a shame that we're
>> having to force static linking of libgcc for this one case.
>
> The i386 target does it all the time for its __x86.get_pc_thunk.?x thingys.
Thanks for the pointer. Here's a patch that takes the same approach.
There's no problem relying on comdat groups here, since MIPS16 TLS
requires 2.22 gas and ld anyway.
Tested on mips64-linux-gnu, mips-sde-elf and various other mips*-elf targets.
Applied.
Richard
gcc/
* config/mips/mips.c (mips_need_mips16_rdhwr_p): New variable.
(mips_get_tp): Set it. Record that __mips16_rdhwr binds locally.
(mips_start_unique_function, mips_output_mips16_rdhwr)
(mips_code_end): New functions.
(TARGET_ASM_CODE_END): Define.
libgcc/
* config.host (mips64*-*-linux*, mipsisa64*-*-linux*)
(mips*-*-linux*): Remove t-slibgcc-libgcc.
* config/mips/t-mips16 (LIB1ASMFUNCS): Remove __mips16_rdhwr.
* config/mips/mips16.S (__mips16_rdhwr): Delete.
Index: gcc/config/mips/mips.c
===================================================================
--- gcc/config/mips/mips.c 2012-02-18 18:11:13.000000000 +0000
+++ gcc/config/mips/mips.c 2012-02-19 16:27:26.198924095 +0000
@@ -592,6 +592,9 @@ struct target_globals *mips16_globals;
and returned from mips_sched_reorder2. */
static int cached_can_issue_more;
+/* True if the output uses __mips16_rdhwr. */
+static bool mips_need_mips16_rdhwr_p;
+
/* Index R is the smallest register class that contains register R. */
const enum reg_class mips_regno_to_class[FIRST_PSEUDO_REGISTER] = {
LEA_REGS, LEA_REGS, M16_REGS, V1_REG,
@@ -2842,7 +2845,9 @@ mips_get_tp (void)
tp = gen_reg_rtx (Pmode);
if (TARGET_MIPS16)
{
+ mips_need_mips16_rdhwr_p = true;
fn = mips16_stub_function ("__mips16_rdhwr");
+ SYMBOL_REF_FLAGS (fn) |= SYMBOL_FLAG_LOCAL;
if (!call_insn_operand (fn, VOIDmode))
fn = force_reg (Pmode, fn);
emit_insn (PMODE_INSN (gen_tls_get_tp_mips16, (tp, fn)));
@@ -5827,6 +5832,33 @@ mips_gimplify_va_arg_expr (tree valist,
return addr;
}
+/* Declare a unique, locally-binding function called NAME, then start
+ its definition. */
+
+static void
+mips_start_unique_function (const char *name)
+{
+ tree decl;
+
+ decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL,
+ get_identifier (name),
+ build_function_type_list (void_type_node, NULL_TREE));
+ DECL_RESULT (decl) = build_decl (BUILTINS_LOCATION, RESULT_DECL,
+ NULL_TREE, void_type_node);
+ TREE_PUBLIC (decl) = 1;
+ TREE_STATIC (decl) = 1;
+
+ DECL_COMDAT_GROUP (decl) = DECL_ASSEMBLER_NAME (decl);
+
+ targetm.asm_out.unique_section (decl, 0);
+ switch_to_section (get_named_section (decl, NULL, 0));
+
+ targetm.asm_out.globalize_label (asm_out_file, name);
+ fputs ("\t.hidden\t", asm_out_file);
+ assemble_name (asm_out_file, name);
+ putc ('\n', asm_out_file);
+}
+
/* Start a definition of function NAME. MIPS16_P indicates whether the
function contains MIPS16 code. */
@@ -5865,6 +5897,26 @@ mips_end_function_definition (const char
}
}
+/* Output a definition of the __mips16_rdhwr function. */
+
+static void
+mips_output_mips16_rdhwr (void)
+{
+ const char *name;
+
+ name = "__mips16_rdhwr";
+ mips_start_unique_function (name);
+ mips_start_function_definition (name, false);
+ fprintf (asm_out_file,
+ "\t.set\tpush\n"
+ "\t.set\tmips32r2\n"
+ "\t.set\tnoreorder\n"
+ "\trdhwr\t$3,$29\n"
+ "\t.set\tpop\n"
+ "\tj\t$31\n");
+ mips_end_function_definition (name);
+}
+
/* Return true if calls to X can use R_MIPS_CALL* relocations. */
static bool
@@ -8467,6 +8519,15 @@ mips_file_start (void)
ASM_COMMENT_START,
mips_small_data_threshold, mips_arch_info->name, mips_isa);
}
+
+/* Implement TARGET_ASM_CODE_END. */
+
+static void
+mips_code_end (void)
+{
+ if (mips_need_mips16_rdhwr_p)
+ mips_output_mips16_rdhwr ();
+}
/* Make the last instruction frame-related and note that it performs
the operation described by FRAME_PATTERN. */
@@ -17357,6 +17418,8 @@ #define TARGET_PREFERRED_RELOAD_CLASS mi
#define TARGET_ASM_FILE_START mips_file_start
#undef TARGET_ASM_FILE_START_FILE_DIRECTIVE
#define TARGET_ASM_FILE_START_FILE_DIRECTIVE true
+#undef TARGET_ASM_CODE_END
+#define TARGET_ASM_CODE_END mips_code_end
#undef TARGET_INIT_LIBFUNCS
#define TARGET_INIT_LIBFUNCS mips_init_libfuncs
Index: libgcc/config.host
===================================================================
--- libgcc/config.host 2012-02-18 18:10:21.000000000 +0000
+++ libgcc/config.host 2012-02-19 07:58:16.415998843 +0000
@@ -746,12 +746,12 @@ mips*-*-netbsd*) # NetBSD/mips, either
;;
mips64*-*-linux* | mipsisa64*-*-linux*)
extra_parts="$extra_parts crtfastmath.o"
- tmake_file="${tmake_file} t-crtfm mips/t-mips16 mips/t-tpbit
t-slibgcc-libgcc"
+ tmake_file="${tmake_file} t-crtfm mips/t-mips16 mips/t-tpbit"
md_unwind_header=mips/linux-unwind.h
;;
mips*-*-linux*) # Linux MIPS, either endian.
extra_parts="$extra_parts crtfastmath.o"
- tmake_file="${tmake_file} t-crtfm mips/t-mips16 t-slibgcc-libgcc"
+ tmake_file="${tmake_file} t-crtfm mips/t-mips16"
md_unwind_header=mips/linux-unwind.h
;;
mips*-*-openbsd*)
Index: libgcc/config/mips/t-mips16
===================================================================
--- libgcc/config/mips/t-mips16 2012-02-18 18:10:21.000000000 +0000
+++ libgcc/config/mips/t-mips16 2012-02-19 07:58:16.455998841 +0000
@@ -36,8 +36,7 @@ LIB1ASMFUNCS = _m16addsf3 _m16subsf3 _m1
_m16stubsc0 _m16stubsc1 _m16stubsc2 _m16stubsc5 _m16stubsc6 \
_m16stubsc9 _m16stubsc10 \
_m16stubdc0 _m16stubdc1 _m16stubdc2 _m16stubdc5 _m16stubdc6 \
- _m16stubdc9 _m16stubdc10 \
- _m16rdhwr
+ _m16stubdc9 _m16stubdc10
SYNC = yes
SYNC_CFLAGS = -mno-mips16
Index: libgcc/config/mips/mips16.S
===================================================================
--- libgcc/config/mips/mips16.S 2012-02-18 18:10:40.000000000 +0000
+++ libgcc/config/mips/mips16.S 2012-02-19 08:00:15.012998552 +0000
@@ -718,17 +718,4 @@ CALL_STUB_RET (__mips16_call_stub_dc_10,
#endif
#endif /* !__mips_single_float */
-#ifdef L_m16rdhwr
-STARTFN (__mips16_rdhwr)
- /* Forced always hidden, because the PLT resolver function would
- not preserve all necessary registers. */
- .hidden __mips16_rdhwr
- .set push
- .set mips32r2
- .set noreorder
- rdhwr $3,$29
- .set pop
- j $31
- ENDFN (__mips16_rdhwr)
-#endif
#endif
