+2004-11-23 Andreas Krebbel <krebbel1@de.ibm.com>
+
+ * config/s390/s390.c (s390_backchain_string): Removed.
+ (s390_return_addr_rtx, s390_back_chain_rtx, s390_frame_info)
+ (s390_emit_prologue, s390_va_start, s390_gimplify_va_arg):
+ Changed users of TARGET_BACKCHAIN, TARGET_NO_BACKCHAIN and
+ TARGET_KERNEL_BACKCHAIN to reflect the new options.
+ * config/s390/s390.h (MASK_BACKCHAIN, MASK_PACKED_STACK): New macros.
+ (TARGET_KERNEL_BACKCHAIN): Removed.
+ (TARGET_BACKCHAIN): Former triple state option change to a target flag.
+ (TARGET_PACKED_STACK): New macro.
+ (TARGET_SWITCHES): New switches added.
+ (TARGET_OPTIONS): "backchain", "no-backchain" and "kernel-backchain"
+ removed.
+ (DYNAMIC_CHAIN_ADDRESS): Use TARGET_PACKED_STACK.
+ * config/s390/s390.md ("allocate_stack", "restore_stack_block")
+ ("save_stack_nonlocal", "restore_stack_nonlocal"): Modified to reflect
+ the change in target switch semantics.
+ * config/s390/tpf.h (TARGET_DEFAULT_BACKCHAIN): Removed.
+ (TARGET_DEFAULT): MASK_BACKCHAIN added.
+ * doc/invoke.texi: Added documentation for the new/changed options.
+
2004-11-23 Uros Bizjak <uros@kss-loka.si>
PR rtl-optimization/18614
const char *s390_tune_string; /* for -mtune=<xxx> */
const char *s390_arch_string; /* for -march=<xxx> */
-/* String to specify backchain mode:
- "" no-backchain, "1" backchain, "2" kernel-backchain. */
-const char *s390_backchain_string = TARGET_DEFAULT_BACKCHAIN;
-
const char *s390_warn_framesize_string;
const char *s390_warn_dynamicstack_string;
const char *s390_stack_size_string;
/* Without backchain, we fail for all but the current frame. */
- if (!TARGET_BACKCHAIN && !TARGET_KERNEL_BACKCHAIN && count > 0)
+ if (!TARGET_BACKCHAIN && count > 0)
return NULL_RTX;
/* For the current frame, we need to make sure the initial
return gen_rtx_MEM (Pmode, return_address_pointer_rtx);
}
- if (TARGET_BACKCHAIN)
- offset = RETURN_REGNUM * UNITS_PER_WORD;
- else
+ if (TARGET_PACKED_STACK)
offset = -2 * UNITS_PER_WORD;
+ else
+ offset = RETURN_REGNUM * UNITS_PER_WORD;
addr = plus_constant (frame, offset);
addr = memory_address (Pmode, addr);
{
rtx chain;
- gcc_assert (TARGET_BACKCHAIN || TARGET_KERNEL_BACKCHAIN);
+ gcc_assert (TARGET_BACKCHAIN);
- if (TARGET_BACKCHAIN)
- chain = stack_pointer_rtx;
- else
+ if (TARGET_PACKED_STACK)
chain = plus_constant (stack_pointer_rtx,
STACK_POINTER_OFFSET - UNITS_PER_WORD);
+ else
+ chain = stack_pointer_rtx;
chain = gen_rtx_MEM (Pmode, chain);
return chain;
if (!TARGET_64BIT && cfun_frame_layout.frame_size > 0x7fff0000)
fatal_error ("Total size of local variables exceeds architecture limit.");
- cfun_frame_layout.save_backchain_p = (TARGET_BACKCHAIN
- || TARGET_KERNEL_BACKCHAIN);
+ cfun_frame_layout.save_backchain_p = TARGET_BACKCHAIN;
- if (TARGET_BACKCHAIN)
+ if (!TARGET_PACKED_STACK)
{
cfun_frame_layout.backchain_offset = 0;
cfun_frame_layout.f0_offset = 16 * UNITS_PER_WORD;
cfun_frame_layout.gprs_offset = (cfun_frame_layout.first_save_gpr
* UNITS_PER_WORD);
}
- else if (TARGET_KERNEL_BACKCHAIN)
+ else if (TARGET_BACKCHAIN) /* kernel stack layout */
{
cfun_frame_layout.backchain_offset = (STACK_POINTER_OFFSET
- UNITS_PER_WORD);
&& !current_function_stdarg)
return;
- if (TARGET_BACKCHAIN)
+ if (!TARGET_PACKED_STACK)
cfun_frame_layout.frame_size += (STARTING_FRAME_OFFSET
+ cfun_frame_layout.high_fprs * 8);
else
save_fpr (stack_pointer_rtx, offset, i + 16);
offset += 8;
}
- else if (TARGET_BACKCHAIN)
+ else if (!TARGET_PACKED_STACK)
offset += 8;
}
if (!call_really_used_regs[i + 16])
RTX_FRAME_RELATED_P (insn) = 1;
}
- else if (TARGET_BACKCHAIN)
+ else if (!TARGET_PACKED_STACK)
offset += 8;
}
- if (!TARGET_BACKCHAIN
+ if (TARGET_PACKED_STACK
&& cfun_save_high_fprs_p
&& cfun_frame_layout.f8_offset + cfun_frame_layout.high_fprs * 8 > 0)
{
next_fpr = i + 16;
}
- if (TARGET_BACKCHAIN)
+ if (!TARGET_PACKED_STACK)
next_fpr = cfun_save_high_fprs_p ? 31 : 0;
/* Decrement stack pointer. */
offset + next_offset, i);
next_offset += 8;
}
- else if (TARGET_BACKCHAIN)
+ else if (!TARGET_PACKED_STACK)
next_offset += 8;
}
/* Find the register save area. */
t = make_tree (TREE_TYPE (sav), return_address_pointer_rtx);
- if (TARGET_KERNEL_BACKCHAIN)
+ if (TARGET_BACKCHAIN && TARGET_PACKED_STACK) /* kernel stack layout */
t = build (PLUS_EXPR, TREE_TYPE (sav), t,
build_int_cst (NULL_TREE,
-(RETURN_REGNUM - 2) * UNITS_PER_WORD
reg = gpr;
n_reg = 1;
- /* TARGET_KERNEL_BACKCHAIN on 31 bit: It is assumed here that no padding
+ /* kernel stack layout on 31 bit: It is assumed here that no padding
will be added by s390_frame_info because for va_args always an even
number of gprs has to be saved r15-r2 = 14 regs. */
- sav_ofs = (TARGET_KERNEL_BACKCHAIN
- ? (TARGET_64BIT ? 4 : 2) * 8 : 2 * UNITS_PER_WORD);
+ sav_ofs = ((TARGET_BACKCHAIN && TARGET_PACKED_STACK) ?
+ (TARGET_64BIT ? 4 : 2) * 8 : 2 * UNITS_PER_WORD);
sav_scale = UNITS_PER_WORD;
size = UNITS_PER_WORD;
max_reg = 4;
indirect_p = 0;
reg = fpr;
n_reg = 1;
- sav_ofs = TARGET_KERNEL_BACKCHAIN ? 0 : 16 * UNITS_PER_WORD;
+ sav_ofs = ((TARGET_BACKCHAIN && TARGET_PACKED_STACK) ?
+ 0 : 16 * UNITS_PER_WORD);
sav_scale = 8;
/* TARGET_64BIT has up to 4 parameter in fprs */
max_reg = TARGET_64BIT ? 3 : 1;
reg = gpr;
n_reg = (size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
- /* TARGET_KERNEL_BACKCHAIN on 31 bit: It is assumed here that no padding
- will be added by s390_frame_info because for va_args always an even
- number of gprs has to be saved r15-r2 = 14 regs. */
- sav_ofs = TARGET_KERNEL_BACKCHAIN ?
- (TARGET_64BIT ? 4 : 2) * 8 : 2*UNITS_PER_WORD;
+ /* kernel stack layout on 31 bit: It is assumed here that no padding
+ will be added by s390_frame_info because for va_args always an even
+ number of gprs has to be saved r15-r2 = 14 regs. */
+ sav_ofs = ((TARGET_BACKCHAIN && TARGET_PACKED_STACK) ?
+ (TARGET_64BIT ? 4 : 2) * 8 : 2 * UNITS_PER_WORD);
if (size < UNITS_PER_WORD)
sav_ofs += UNITS_PER_WORD - size;
extern enum processor_flags s390_arch_flags;
extern const char *s390_arch_string;
-extern const char *s390_backchain_string;
-
extern const char *s390_warn_framesize_string;
extern const char *s390_warn_dynamicstack_string;
extern const char *s390_stack_size_string;
#define MASK_MVCLE 0x40
#define MASK_TPF_PROFILING 0x80
#define MASK_NO_FUSED_MADD 0x100
+#define MASK_BACKCHAIN 0x200
+#define MASK_PACKED_STACK 0x400
#define TARGET_HARD_FLOAT (target_flags & MASK_HARD_FLOAT)
#define TARGET_SOFT_FLOAT (!(target_flags & MASK_HARD_FLOAT))
#define TARGET_TPF_PROFILING (target_flags & MASK_TPF_PROFILING)
#define TARGET_NO_FUSED_MADD (target_flags & MASK_NO_FUSED_MADD)
#define TARGET_FUSED_MADD (! TARGET_NO_FUSED_MADD)
-
-#define TARGET_BACKCHAIN (s390_backchain_string[0] == '1')
-#define TARGET_KERNEL_BACKCHAIN (s390_backchain_string[0] == '2')
+#define TARGET_BACKCHAIN (target_flags & MASK_BACKCHAIN)
+#define TARGET_PACKED_STACK (target_flags & MASK_PACKED_STACK)
/* ??? Once this actually works, it could be made a runtime option. */
#define TARGET_IBM_FLOAT 0
#define TARGET_DEFAULT MASK_HARD_FLOAT
#endif
-#define TARGET_DEFAULT_BACKCHAIN ""
-
-#define TARGET_SWITCHES \
-{ { "hard-float", 1, N_("Use hardware fp")}, \
- { "soft-float", -1, N_("Don't use hardware fp")}, \
- { "small-exec", 4, N_("Use bras for executable < 64k")}, \
- { "no-small-exec", -4, N_("Don't use bras")}, \
- { "debug", 8, N_("Additional debug prints")}, \
- { "no-debug", -8, N_("Don't print additional debug prints")}, \
- { "64", 16, N_("64 bit ABI")}, \
- { "31", -16, N_("31 bit ABI")}, \
- { "zarch", 32, N_("z/Architecture")}, \
- { "esa", -32, N_("ESA/390 architecture")}, \
- { "mvcle", 64, N_("mvcle use")}, \
- { "no-mvcle", -64, N_("mvc&ex")}, \
- { "tpf-trace", 128, N_("enable tpf OS tracing code")}, \
- { "no-tpf-trace", -128, N_("disable tpf OS tracing code")}, \
- { "no-fused-madd", 256, N_("disable fused multiply/add instructions")},\
- { "fused-madd", -256, N_("enable fused multiply/add instructions")}, \
+#define TARGET_SWITCHES \
+{ { "hard-float", 1, N_("Use hardware fp")}, \
+ { "soft-float", -1, N_("Don't use hardware fp")}, \
+ { "small-exec", 4, N_("Use bras for executable < 64k")}, \
+ { "no-small-exec", -4, N_("Don't use bras")}, \
+ { "debug", 8, N_("Additional debug prints")}, \
+ { "no-debug", -8, N_("Don't print additional debug prints")}, \
+ { "64", 16, N_("64 bit ABI")}, \
+ { "31", -16, N_("31 bit ABI")}, \
+ { "zarch", 32, N_("z/Architecture")}, \
+ { "esa", -32, N_("ESA/390 architecture")}, \
+ { "mvcle", 64, N_("mvcle use")}, \
+ { "no-mvcle", -64, N_("mvc&ex")}, \
+ { "tpf-trace", 128, N_("Enable tpf OS tracing code")}, \
+ { "no-tpf-trace", -128, N_("Disable tpf OS tracing code")}, \
+ { "no-fused-madd", 256, N_("Disable fused multiply/add instructions")},\
+ { "fused-madd", -256, N_("Enable fused multiply/add instructions")}, \
+ { "backchain", 512, N_("Maintain backchain pointer")}, \
+ { "no-backchain", -512, N_("Don't maintain backchain pointer")}, \
+ { "packed-stack", 1024, N_("Use packed stack layout")}, \
+ { "no-packed-stack", -1024, N_("Don't use packed stack layout")}, \
{ "", TARGET_DEFAULT, 0 } }
#define TARGET_OPTIONS \
N_("Schedule code for given CPU"), 0}, \
{ "arch=", &s390_arch_string, \
N_("Generate code for given CPU"), 0}, \
- { "backchain", &s390_backchain_string, \
- N_("Set backchain"), "1"}, \
- { "no-backchain", &s390_backchain_string, \
- N_("Do not set backchain"), ""}, \
- { "kernel-backchain", &s390_backchain_string, \
- N_("Set backchain appropriate for the linux kernel"), "2"}, \
{ "warn-framesize=", &s390_warn_framesize_string, \
N_("Warn if a single function's framesize exceeds the given framesize"), \
0}, \
the corresponding RETURN_REGNUM register was saved. */
#define DYNAMIC_CHAIN_ADDRESS(FRAME) \
- (TARGET_BACKCHAIN ? \
- ((FRAME) != hard_frame_pointer_rtx ? (FRAME) : \
- plus_constant (arg_pointer_rtx, -STACK_POINTER_OFFSET)) : \
+ (TARGET_PACKED_STACK ? \
((FRAME) != hard_frame_pointer_rtx ? \
plus_constant ((FRAME), STACK_POINTER_OFFSET - UNITS_PER_WORD) : \
- plus_constant (arg_pointer_rtx, -UNITS_PER_WORD)))
+ plus_constant (arg_pointer_rtx, -UNITS_PER_WORD)) : \
+ ((FRAME) != hard_frame_pointer_rtx ? (FRAME) : \
+ plus_constant (arg_pointer_rtx, -STACK_POINTER_OFFSET)))
#define RETURN_ADDR_RTX(COUNT, FRAME) \
s390_return_addr_rtx ((COUNT), DYNAMIC_CHAIN_ADDRESS ((FRAME)))
(define_expand "allocate_stack"
[(match_operand 0 "general_operand" "")
(match_operand 1 "general_operand" "")]
- "TARGET_BACKCHAIN || TARGET_KERNEL_BACKCHAIN"
+ "TARGET_BACKCHAIN"
{
rtx temp = gen_reg_rtx (Pmode);
(define_expand "restore_stack_block"
[(match_operand 0 "register_operand" "")
(match_operand 1 "register_operand" "")]
- "TARGET_BACKCHAIN || TARGET_KERNEL_BACKCHAIN"
+ "TARGET_BACKCHAIN"
{
rtx temp = gen_reg_rtx (Pmode);
/* Copy the backchain to the first word, sp to the second and the
literal pool base to the third. */
- if (TARGET_BACKCHAIN || TARGET_KERNEL_BACKCHAIN)
+ if (TARGET_BACKCHAIN)
{
rtx temp = force_reg (Pmode, s390_back_chain_rtx ());
emit_move_insn (operand_subword (operands[0], 0, 0, mode), temp);
/* Restore the backchain from the first word, sp from the second and the
literal pool base from the third. */
- if (TARGET_BACKCHAIN || TARGET_KERNEL_BACKCHAIN)
+ if (TARGET_BACKCHAIN)
temp = force_reg (Pmode, operand_subword (operands[1], 0, 0, mode));
emit_move_insn (base, operand_subword (operands[1], 2, 0, mode));
Also, enable TPF profiling support and the standard backchain by default. */
#undef TARGET_DEFAULT
#define TARGET_DEFAULT (MASK_64BIT | MASK_ZARCH | MASK_HARD_FLOAT \
- | MASK_TPF_PROFILING)
-#undef TARGET_DEFAULT_BACKCHAIN
-#define TARGET_DEFAULT_BACKCHAIN "1"
-
+ | MASK_TPF_PROFILING | MASK_BACKCHAIN)
/* Exception handling. */
/* Select a format to encode pointers in exception handling data. */
@emph{S/390 and zSeries Options}
@gccoptlist{-mtune=@var{cpu-type} -march=@var{cpu-type} @gol
--mhard-float -msoft-float -mbackchain -mno-backchain -mkernel-backchain @gol
+-mhard-float -msoft-float -mbackchain -mno-backchain @gol
+-mpacked-stack -mno-packed-stack @gol
-msmall-exec -mno-small-exec -mmvcle -mno-mvcle @gol
-m64 -m31 -mdebug -mno-debug -mesa -mzarch @gol
-mtpf-trace -mno-tpf-trace -mfused-madd -mno-fused-madd @gol
@item -mbackchain
@itemx -mno-backchain
-@itemx -mkernel-backchain
@opindex mbackchain
@opindex mno-backchain
-@opindex mkernel-backchain
-In order to provide a backchain the address of the caller's frame
-is stored within the callee's stack frame.
+Store (do not store) the address of the caller's frame as backchain pointer
+into the callee's stack frame.
A backchain may be needed to allow debugging using tools that do not understand
DWARF-2 call frame information.
-For @option{-mno-backchain} no backchain is maintained at all which is the
-default.
-If one of the other options is present the backchain pointer is placed either
-on top of the stack frame (@option{-mkernel-backchain}) or on
-the bottom (@option{-mbackchain}).
-Beside the different backchain location @option{-mkernel-backchain}
-also changes stack frame layout breaking the ABI@. This option
-is intended to be used for code which internally needs a backchain but has
-to get by with a limited stack size e.g.@: the linux kernel.
-Internal unwinding code not using DWARF-2 info has to be able to locate the
-return address of a function. That will be eased be the fact that
-the return address of a function is placed two words below the backchain
-pointer.
+When @option{-mno-packed-stack} is in effect, the backchain pointer is stored
+at the bottom of the stack frame; when @option{-mpacked-stack} is in effect,
+the backchain is placed into the topmost word of the 96/160 byte register
+save area.
+
+In general, code compiled with @option{-mbackchain} is call-compatible with
+code compiled with @option{-mmo-backchain}; however, use of the backchain
+for debugging purposes usually requires that the whole binary is built with
+@option{-mbackchain}. Note that the combination of @option{-mbackchain} and
+@option{-mpacked-stack} generates code that is not ABI-compatible.
+
+The default is to not maintain the backchain.
+
+@item -mpacked-stack
+@item -mno-packed-stack
+@opindex mpacked-stack
+@opindex mno-packed-stack
+Use (do not use) the packed stack layout. When @option{-mno-packed-stack} is
+specified, the compiler uses the all fields of the 96/160 byte register save
+area only for their default purpose; unused fields still take up stack space.
+When @option{-mpacked-stack} is specified, register save slots are densely
+packed at the top of the register save area; unused space is reused for other
+purposes, allowing for more efficient use of the available stack space.
+However, when @option{-mbackchain} is also in effect, the topmost word of
+the save area is always used to store the backchain, and the return address
+register is always saved two words below the backchain.
+
+As long as the stack frame backchain is not used, code generated with
+@option{-mpacked-stack} is call-compatible with code generated with
+@option{-mno-packed-stack}. Note that some non-FSF releases of GCC 2.95 for
+S/390 or zSeries generated code that uses the stack frame backchain at run
+time, not just for debugging purposes. Such code is not call-compatible
+with code compiled with @option{-mpacked-stack}. Also, note that the
+combination of @option{-mbackchain} and @option{-mpacked-stack} generates code
+that is not ABI-compatible.
+
+The default is to not use the packed stack layout.
@item -msmall-exec
@itemx -mno-small-exec
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