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Fix PR target/20446
- From: Eric Botcazou <ebotcazou at libertysurf dot fr>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 4 Apr 2005 17:19:04 +0200
- Subject: Fix PR target/20446
The compiler produces broken assembly code at -O0 -fPIC -gstabs+ on a big C++
testcase involving virtual inheritance, a regression from 3.4 branch:
as: "sugarconverter.s", line 873: error: can't compute difference between
symbols in different segments
The problem comes from the mix of thunks and -fPIC in the SPARC back-end: both
generate assembly directly and don't play nice with each other at -O0 because
thunks go through the GOT instead of using a sibcall (-fdelayed-branch is
disabled at -O0).
Fixed by deferring the special PIC helper when a thunk is the first function
that goes through the GOT. Bootstrapped/regtested on SPARC/Solaris 2.5, 2.6,
7, 8 and 9 and tested with crosses to sparc-linux and sparc64-linux.
Applied to mainline and 4.0 branch.
2005-04-04 Eric Botcazou <ebotcazou@libertysurf.fr>
PR target/20446
* config/sparc/sparc.h (NEED_INDICATE_EXEC_STACK): Define to 0.
* config/sparc/linux.h (TARGET_ASM_FILE_END): Delete.
(NEED_INDICATE_EXEC_STACK): Define to 1.
* config/sparc/linux64.h (TARGET_ASM_FILE_END): Delete.
(NEED_INDICATE_EXEC_STACK): Define to 1.
* config/sparc/sparc.c (TARGET_ASM_FILE_END): Set to sparc_file_end.
(add_pc_to_pic_symbol): Rename into pic_helper_symbol.
(add_pc_to_pic_symbol_name): Rename into pic_helper_symbol_name.
(pic_helper_emitted_p): New global.
(emit_pic_helper): New function extracted from...
(load_pic_register): ...here. Add 'delay_pic_helper' parameter.
Do not call emit_pic_helper if delay_pic_helper is true.
(sparc_expand_prologue): Pass 'false' to load_pic_register.
(sparc_output_mi_thunk): Pass 'true' to load_pic_register.
(sparc_file_end): New function.
--
Eric Botcazou
Index: config/sparc/linux.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/sparc/linux.h,v
retrieving revision 1.68
diff -u -p -r1.68 linux.h
--- config/sparc/linux.h 20 Jan 2005 20:39:42 -0000 1.68
+++ config/sparc/linux.h 29 Mar 2005 16:24:28 -0000
@@ -209,8 +209,6 @@ do { \
#undef CTORS_SECTION_ASM_OP
#undef DTORS_SECTION_ASM_OP
-#define TARGET_ASM_FILE_END file_end_indicate_exec_stack
-
/* Determine whether the the entire c99 runtime is present in the
runtime library. */
#define TARGET_C99_FUNCTIONS 1
@@ -233,3 +231,6 @@ do { \
change their minds. */
#undef SPARC_RELAXED_ORDERING
#define SPARC_RELAXED_ORDERING true
+
+#undef NEED_INDICATE_EXEC_STACK
+#define NEED_INDICATE_EXEC_STACK 1
Index: config/sparc/linux64.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/sparc/linux64.h,v
retrieving revision 1.91
diff -u -p -r1.91 linux64.h
--- config/sparc/linux64.h 21 Jan 2005 10:15:56 -0000 1.91
+++ config/sparc/linux64.h 29 Mar 2005 16:24:29 -0000
@@ -343,8 +343,6 @@ do { \
#undef CTORS_SECTION_ASM_OP
#undef DTORS_SECTION_ASM_OP
-#define TARGET_ASM_FILE_END file_end_indicate_exec_stack
-
/* Determine whether the the entire c99 runtime is present in the
runtime library. */
#define TARGET_C99_FUNCTIONS 1
@@ -367,3 +365,6 @@ do { \
change their minds. */
#undef SPARC_RELAXED_ORDERING
#define SPARC_RELAXED_ORDERING true
+
+#undef NEED_INDICATE_EXEC_STACK
+#define NEED_INDICATE_EXEC_STACK 1
Index: config/sparc/sparc.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/sparc/sparc.c,v
retrieving revision 1.355
diff -u -p -r1.355 sparc.c
--- config/sparc/sparc.c 13 Mar 2005 22:11:46 -0000 1.355
+++ config/sparc/sparc.c 29 Mar 2005 16:24:49 -0000
@@ -314,7 +314,8 @@ static rtx sparc_builtin_saveregs (void)
static int epilogue_renumber (rtx *, int);
static bool sparc_assemble_integer (rtx, unsigned int, int);
static int set_extends (rtx);
-static void load_pic_register (void);
+static void emit_pic_helper (void);
+static void load_pic_register (bool);
static int save_or_restore_regs (int, int, rtx, int, int);
static void emit_save_regs (void);
static void emit_restore_regs (void);
@@ -362,6 +363,7 @@ static bool sparc_pass_by_reference (CUM
static int sparc_arg_partial_bytes (CUMULATIVE_ARGS *,
enum machine_mode, tree, bool);
static void sparc_dwarf_handle_frame_unspec (const char *, rtx, int);
+static void sparc_file_end (void);
#ifdef SUBTARGET_ATTRIBUTE_TABLE
const struct attribute_spec sparc_attribute_table[];
#endif
@@ -504,6 +506,8 @@ enum processor_type sparc_cpu;
#undef TARGET_RELAXED_ORDERING
#define TARGET_RELAXED_ORDERING SPARC_RELAXED_ORDERING
+#define TARGET_ASM_FILE_END sparc_file_end
+
struct gcc_target targetm = TARGET_INITIALIZER;
/* Validate and override various options, and do some machine dependent
@@ -3355,13 +3359,12 @@ sparc_cannot_force_const_mem (rtx x)
}
}
-/* The table we use to reference PIC data. */
+/* PIC support. */
+static GTY(()) char pic_helper_symbol_name[256];
+static GTY(()) rtx pic_helper_symbol;
+static GTY(()) bool pic_helper_emitted_p = false;
static GTY(()) rtx global_offset_table;
-/* The function we use to get at it. */
-static GTY(()) rtx add_pc_to_pic_symbol;
-static GTY(()) char add_pc_to_pic_symbol_name[256];
-
/* Ensure that we are not using patterns that are not OK with PIC. */
int
@@ -3951,46 +3954,57 @@ legitimize_address (rtx x, rtx oldx ATTR
return x;
}
-/* Emit the special PIC prologue. */
+/* Emit the special PIC helper function. */
+
+static void
+emit_pic_helper (void)
+{
+ const char *pic_name = reg_names[REGNO (pic_offset_table_rtx)];
+ int align;
+
+ text_section ();
+
+ align = floor_log2 (FUNCTION_BOUNDARY / BITS_PER_UNIT);
+ if (align > 0)
+ ASM_OUTPUT_ALIGN (asm_out_file, align);
+ ASM_OUTPUT_LABEL (asm_out_file, pic_helper_symbol_name);
+ if (flag_delayed_branch)
+ fprintf (asm_out_file, "\tjmp\t%%o7+8\n\t add\t%%o7, %s, %s\n",
+ pic_name, pic_name);
+ else
+ fprintf (asm_out_file, "\tadd\t%%o7, %s, %s\n\tjmp\t%%o7+8\n\t nop\n",
+ pic_name, pic_name);
+
+ pic_helper_emitted_p = true;
+}
+
+/* Emit code to load the PIC register. */
static void
-load_pic_register (void)
+load_pic_register (bool delay_pic_helper)
{
int orig_flag_pic = flag_pic;
- /* If we haven't emitted the special helper function, do so now. */
- if (add_pc_to_pic_symbol_name[0] == 0)
+ /* If we haven't initialized the special PIC symbols, do so now. */
+ if (!pic_helper_symbol_name[0])
{
- const char *pic_name = reg_names[REGNO (pic_offset_table_rtx)];
- int align;
-
- ASM_GENERATE_INTERNAL_LABEL (add_pc_to_pic_symbol_name, "LADDPC", 0);
- text_section ();
+ ASM_GENERATE_INTERNAL_LABEL (pic_helper_symbol_name, "LADDPC", 0);
+ pic_helper_symbol = gen_rtx_SYMBOL_REF (Pmode, pic_helper_symbol_name);
+ global_offset_table = gen_rtx_SYMBOL_REF (Pmode, "_GLOBAL_OFFSET_TABLE_");
+ }
- align = floor_log2 (FUNCTION_BOUNDARY / BITS_PER_UNIT);
- if (align > 0)
- ASM_OUTPUT_ALIGN (asm_out_file, align);
- ASM_OUTPUT_LABEL (asm_out_file, add_pc_to_pic_symbol_name);
- if (flag_delayed_branch)
- fprintf (asm_out_file, "\tjmp %%o7+8\n\t add\t%%o7, %s, %s\n",
- pic_name, pic_name);
- else
- fprintf (asm_out_file, "\tadd\t%%o7, %s, %s\n\tjmp %%o7+8\n\t nop\n",
- pic_name, pic_name);
- }
-
- /* Initialize every time through, since we can't easily
- know this to be permanent. */
- global_offset_table = gen_rtx_SYMBOL_REF (Pmode, "_GLOBAL_OFFSET_TABLE_");
- add_pc_to_pic_symbol = gen_rtx_SYMBOL_REF (Pmode, add_pc_to_pic_symbol_name);
+ /* If we haven't emitted the special PIC helper function, do so now unless
+ we are requested to delay it. */
+ if (!delay_pic_helper && !pic_helper_emitted_p)
+ emit_pic_helper ();
flag_pic = 0;
if (TARGET_ARCH64)
emit_insn (gen_load_pcrel_symdi (pic_offset_table_rtx, global_offset_table,
- add_pc_to_pic_symbol));
+ pic_helper_symbol));
else
emit_insn (gen_load_pcrel_symsi (pic_offset_table_rtx, global_offset_table,
- add_pc_to_pic_symbol));
+ pic_helper_symbol));
flag_pic = orig_flag_pic;
/* Need to emit this whether or not we obey regdecls,
@@ -4639,7 +4653,7 @@ sparc_expand_prologue (void)
/* Load the PIC register if needed. */
if (flag_pic && current_function_uses_pic_offset_table)
- load_pic_register ();
+ load_pic_register (false);
}
/* This function generates the assembly code for function entry, which boils
@@ -9061,7 +9075,9 @@ sparc_output_mi_thunk (FILE *file, tree
{
spill_reg = gen_rtx_REG (word_mode, 15); /* %o7 */
start_sequence ();
- load_pic_register (); /* clobbers %o7 */
+ /* Delay emitting the PIC helper function because it needs to
+ change the section and we are emitting assembly code. */
+ load_pic_register (true); /* clobbers %o7 */
scratch = legitimize_pic_address (funexp, Pmode, scratch);
seq = get_insns ();
end_sequence ();
@@ -9212,4 +9228,15 @@ sparc_output_dwarf_dtprel (FILE *file, i
fputs (")", file);
}
+static
+void sparc_file_end (void)
+{
+ /* If we haven't emitted the special PIC helper function, do so now. */
+ if (pic_helper_symbol_name[0] && !pic_helper_emitted_p)
+ emit_pic_helper ();
+
+ if (NEED_INDICATE_EXEC_STACK)
+ file_end_indicate_exec_stack ();
+}
+
#include "gt-sparc.h"
Index: config/sparc/sparc.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/sparc/sparc.h,v
retrieving revision 1.273
diff -u -p -r1.273 sparc.h
--- config/sparc/sparc.h 21 Jan 2005 10:15:56 -0000 1.273
+++ config/sparc/sparc.h 29 Mar 2005 16:24:58 -0000
@@ -214,6 +214,9 @@ extern enum cmodel sparc_cmodel;
total memory ordering (TMO). */
#define SPARC_RELAXED_ORDERING false
+/* Do not use the .note.GNU-stack convention by default. */
+#define NEED_INDICATE_EXEC_STACK 0
+
/* This is call-clobbered in the normal ABI, but is reserved in the
home grown (aka upward compatible) embedded ABI. */
#define EMBMEDANY_BASE_REG "%g4"