* [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
@ 2015-12-16 23:29 H.J. Lu
2015-12-17 10:04 ` Uros Bizjak
0 siblings, 1 reply; 11+ messages in thread
From: H.J. Lu @ 2015-12-16 23:29 UTC (permalink / raw)
To: gcc-patches; +Cc: Uros Bizjak
Since sibcall never returns, we can only use call-clobbered register
as GOT base. Otherwise, callee-saved register used as GOT base won't
be properly restored.
Tested on x86-64 with -m32. OK for trunk?
H.J.
---
gcc/
PR target/68937
* config/i386/i386.c (ix86_function_ok_for_sibcall): Count
call via GOT slot as indirect call.
(ix86_expand_call): Mark PIC register used for sibcall as
call-clobbered.
* config/i386/i386.md (*sibcall_GOT_32): New pattern.
(*sibcall_value_GOT_32): Likewise.
gcc/testsuite/
PR target/68937
* gcc.target/i386/pr68937-1.c: New test.
* gcc.target/i386/pr68937-2.c: Likewise.
* gcc.target/i386/pr68937-3.c: Likewise.
* gcc.target/i386/pr68937-4.c: Likewise.
---
gcc/config/i386/i386.c | 15 ++++++++---
gcc/config/i386/i386.md | 45 +++++++++++++++++++++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-1.c | 13 +++++++++
gcc/testsuite/gcc.target/i386/pr68937-2.c | 13 +++++++++
gcc/testsuite/gcc.target/i386/pr68937-3.c | 13 +++++++++
gcc/testsuite/gcc.target/i386/pr68937-4.c | 13 +++++++++
6 files changed, 109 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-4.c
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index cecea24..ebc9d09 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6723,8 +6723,10 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
/* If this call is indirect, we'll need to be able to use a
call-clobbered register for the address of the target function.
Make sure that all such registers are not used for passing
- parameters. Note that DLLIMPORT functions are indirect. */
+ parameters. Note that DLLIMPORT functions and call via GOT
+ slot are indirect. */
if (!decl
+ || (flag_pic && !flag_plt)
|| (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
{
/* Check if regparm >= 3 since arg_reg_available is set to
@@ -27019,8 +27021,8 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
rtx callarg2,
rtx pop, bool sibcall)
{
- rtx vec[3];
- rtx use = NULL, call;
+ rtx vec[4];
+ rtx use = NULL, call, clobber = NULL;
unsigned int vec_len = 0;
if (pop == const0_rtx)
@@ -27075,6 +27077,10 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr),
UNSPEC_GOT);
fnaddr = gen_rtx_CONST (Pmode, fnaddr);
+ /* Since sibcall never returns, mark PIC register as
+ call-clobbered. */
+ if (sibcall)
+ clobber = pic_offset_table_rtx;
fnaddr = gen_rtx_PLUS (Pmode, pic_offset_table_rtx,
fnaddr);
}
@@ -27151,6 +27157,9 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
}
vec[vec_len++] = call;
+ if (clobber)
+ vec[vec_len++] = gen_rtx_CLOBBER (VOIDmode, clobber);
+
if (pop)
{
pop = gen_rtx_PLUS (Pmode, stack_pointer_rtx, pop);
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 49b2216..65c1534 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -11865,6 +11865,28 @@
"* return ix86_output_call_insn (insn, operands[0]);"
[(set_attr "type" "call")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_GOT_32"
+ [(call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 0 "register_operand" "U")
+ (const:SI
+ (unspec:SI [(match_operand:SI 1 "symbol_operand")]
+ UNSPEC_GOT)))))
+ (match_operand 2))
+ (clobber (match_dup 0))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, operands[1]),
+ UNSPEC_GOT);
+ fnaddr = gen_rtx_CONST (Pmode, fnaddr);
+ fnaddr = gen_rtx_PLUS (Pmode, operands[0], fnaddr);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "call")])
+
(define_insn "*sibcall"
[(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "UBsBz"))
(match_operand 1))]
@@ -12042,6 +12064,29 @@
"* return ix86_output_call_insn (insn, operands[1]);"
[(set_attr "type" "callv")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_value_GOT_32"
+ [(set (match_operand 0)
+ (call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 1 "register_operand" "U")
+ (const:SI
+ (unspec:SI [(match_operand:SI 2 "symbol_operand")]
+ UNSPEC_GOT)))))
+ (match_operand 3)))
+ (clobber (match_dup 1))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, operands[2]),
+ UNSPEC_GOT);
+ fnaddr = gen_rtx_CONST (Pmode, fnaddr);
+ fnaddr = gen_rtx_PLUS (Pmode, operands[1], fnaddr);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "callv")])
+
(define_insn "*sibcall_value"
[(set (match_operand 0)
(call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "UBsBz"))
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-1.c b/gcc/testsuite/gcc.target/i386/pr68937-1.c
new file mode 100644
index 0000000..166c309
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-1.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int);
+
+void
+foo (int b)
+{
+ bar (b);
+ bar (b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-2.c b/gcc/testsuite/gcc.target/i386/pr68937-2.c
new file mode 100644
index 0000000..9aa4f4d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-2.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int);
+
+void
+foo (int a, int b)
+{
+ bar (a, b);
+ bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" { target ia32 } } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-3.c b/gcc/testsuite/gcc.target/i386/pr68937-3.c
new file mode 100644
index 0000000..6d8e40f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-3.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int, int);
+
+void
+foo (int a, int b, int c)
+{
+ bar (a, b, c);
+ bar (a, b, c);
+}
+
+/* { dg-final { scan-assembler-not "jmp\[ \t\]*.bar@GOT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-4.c b/gcc/testsuite/gcc.target/i386/pr68937-4.c
new file mode 100644
index 0000000..fc5f2a6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-4.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern int bar (int, int);
+
+int
+foo (int a, int b)
+{
+ (void) bar (a, b);
+ return bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" { target ia32 } } } */
--
2.5.0
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-16 23:29 [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall H.J. Lu
@ 2015-12-17 10:04 ` Uros Bizjak
2015-12-17 13:00 ` H.J. Lu
0 siblings, 1 reply; 11+ messages in thread
From: Uros Bizjak @ 2015-12-17 10:04 UTC (permalink / raw)
To: H.J. Lu; +Cc: gcc-patches
On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> Since sibcall never returns, we can only use call-clobbered register
> as GOT base. Otherwise, callee-saved register used as GOT base won't
> be properly restored.
>
> Tested on x86-64 with -m32. OK for trunk?
You don't have to add explicit clobber for members of "CLOBBERED_REGS"
class, and register_no_elim_operand predicate should be used with "U"
constraint. Also, please introduce new predicate, similar to how
GOT_memory_operand is defined and handled.
Uros.
>
> H.J.
> ---
> gcc/
>
> PR target/68937
> * config/i386/i386.c (ix86_function_ok_for_sibcall): Count
> call via GOT slot as indirect call.
> (ix86_expand_call): Mark PIC register used for sibcall as
> call-clobbered.
> * config/i386/i386.md (*sibcall_GOT_32): New pattern.
> (*sibcall_value_GOT_32): Likewise.
>
> gcc/testsuite/
>
> PR target/68937
> * gcc.target/i386/pr68937-1.c: New test.
> * gcc.target/i386/pr68937-2.c: Likewise.
> * gcc.target/i386/pr68937-3.c: Likewise.
> * gcc.target/i386/pr68937-4.c: Likewise.
> ---
> gcc/config/i386/i386.c | 15 ++++++++---
> gcc/config/i386/i386.md | 45 +++++++++++++++++++++++++++++++
> gcc/testsuite/gcc.target/i386/pr68937-1.c | 13 +++++++++
> gcc/testsuite/gcc.target/i386/pr68937-2.c | 13 +++++++++
> gcc/testsuite/gcc.target/i386/pr68937-3.c | 13 +++++++++
> gcc/testsuite/gcc.target/i386/pr68937-4.c | 13 +++++++++
> 6 files changed, 109 insertions(+), 3 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-1.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-2.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-3.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-4.c
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index cecea24..ebc9d09 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -6723,8 +6723,10 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
> /* If this call is indirect, we'll need to be able to use a
> call-clobbered register for the address of the target function.
> Make sure that all such registers are not used for passing
> - parameters. Note that DLLIMPORT functions are indirect. */
> + parameters. Note that DLLIMPORT functions and call via GOT
> + slot are indirect. */
> if (!decl
> + || (flag_pic && !flag_plt)
> || (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
> {
> /* Check if regparm >= 3 since arg_reg_available is set to
> @@ -27019,8 +27021,8 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
> rtx callarg2,
> rtx pop, bool sibcall)
> {
> - rtx vec[3];
> - rtx use = NULL, call;
> + rtx vec[4];
> + rtx use = NULL, call, clobber = NULL;
> unsigned int vec_len = 0;
>
> if (pop == const0_rtx)
> @@ -27075,6 +27077,10 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
> fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr),
> UNSPEC_GOT);
> fnaddr = gen_rtx_CONST (Pmode, fnaddr);
> + /* Since sibcall never returns, mark PIC register as
> + call-clobbered. */
> + if (sibcall)
> + clobber = pic_offset_table_rtx;
> fnaddr = gen_rtx_PLUS (Pmode, pic_offset_table_rtx,
> fnaddr);
> }
> @@ -27151,6 +27157,9 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
> }
> vec[vec_len++] = call;
>
> + if (clobber)
> + vec[vec_len++] = gen_rtx_CLOBBER (VOIDmode, clobber);
> +
> if (pop)
> {
> pop = gen_rtx_PLUS (Pmode, stack_pointer_rtx, pop);
> diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> index 49b2216..65c1534 100644
> --- a/gcc/config/i386/i386.md
> +++ b/gcc/config/i386/i386.md
> @@ -11865,6 +11865,28 @@
> "* return ix86_output_call_insn (insn, operands[0]);"
> [(set_attr "type" "call")])
>
> +;; Since sibcall never returns, we can only use call-clobbered register
> +;; as GOT base.
> +(define_insn "*sibcall_GOT_32"
> + [(call (mem:QI
> + (mem:SI (plus:SI
> + (match_operand:SI 0 "register_operand" "U")
> + (const:SI
> + (unspec:SI [(match_operand:SI 1 "symbol_operand")]
> + UNSPEC_GOT)))))
> + (match_operand 2))
> + (clobber (match_dup 0))]
> + "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
> +{
> + rtx fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, operands[1]),
> + UNSPEC_GOT);
> + fnaddr = gen_rtx_CONST (Pmode, fnaddr);
> + fnaddr = gen_rtx_PLUS (Pmode, operands[0], fnaddr);
> + fnaddr = gen_const_mem (Pmode, fnaddr);
> + return ix86_output_call_insn (insn, fnaddr);
> +}
> + [(set_attr "type" "call")])
> +
> (define_insn "*sibcall"
> [(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "UBsBz"))
> (match_operand 1))]
> @@ -12042,6 +12064,29 @@
> "* return ix86_output_call_insn (insn, operands[1]);"
> [(set_attr "type" "callv")])
>
> +;; Since sibcall never returns, we can only use call-clobbered register
> +;; as GOT base.
> +(define_insn "*sibcall_value_GOT_32"
> + [(set (match_operand 0)
> + (call (mem:QI
> + (mem:SI (plus:SI
> + (match_operand:SI 1 "register_operand" "U")
> + (const:SI
> + (unspec:SI [(match_operand:SI 2 "symbol_operand")]
> + UNSPEC_GOT)))))
> + (match_operand 3)))
> + (clobber (match_dup 1))]
> + "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
> +{
> + rtx fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, operands[2]),
> + UNSPEC_GOT);
> + fnaddr = gen_rtx_CONST (Pmode, fnaddr);
> + fnaddr = gen_rtx_PLUS (Pmode, operands[1], fnaddr);
> + fnaddr = gen_const_mem (Pmode, fnaddr);
> + return ix86_output_call_insn (insn, fnaddr);
> +}
> + [(set_attr "type" "callv")])
> +
> (define_insn "*sibcall_value"
> [(set (match_operand 0)
> (call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "UBsBz"))
> diff --git a/gcc/testsuite/gcc.target/i386/pr68937-1.c b/gcc/testsuite/gcc.target/i386/pr68937-1.c
> new file mode 100644
> index 0000000..166c309
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr68937-1.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target { *-*-linux* && ia32 } } } */
> +/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
> +
> +extern void bar (int);
> +
> +void
> +foo (int b)
> +{
> + bar (b);
> + bar (b);
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" { target ia32 } } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr68937-2.c b/gcc/testsuite/gcc.target/i386/pr68937-2.c
> new file mode 100644
> index 0000000..9aa4f4d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr68937-2.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target { *-*-linux* && ia32 } } } */
> +/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
> +
> +extern void bar (int, int);
> +
> +void
> +foo (int a, int b)
> +{
> + bar (a, b);
> + bar (a, b);
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" { target ia32 } } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr68937-3.c b/gcc/testsuite/gcc.target/i386/pr68937-3.c
> new file mode 100644
> index 0000000..6d8e40f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr68937-3.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target { *-*-linux* && ia32 } } } */
> +/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
> +
> +extern void bar (int, int, int);
> +
> +void
> +foo (int a, int b, int c)
> +{
> + bar (a, b, c);
> + bar (a, b, c);
> +}
> +
> +/* { dg-final { scan-assembler-not "jmp\[ \t\]*.bar@GOT" } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr68937-4.c b/gcc/testsuite/gcc.target/i386/pr68937-4.c
> new file mode 100644
> index 0000000..fc5f2a6
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr68937-4.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target { *-*-linux* && ia32 } } } */
> +/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
> +
> +extern int bar (int, int);
> +
> +int
> +foo (int a, int b)
> +{
> + (void) bar (a, b);
> + return bar (a, b);
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" { target ia32 } } } */
> --
> 2.5.0
>
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-17 10:04 ` Uros Bizjak
@ 2015-12-17 13:00 ` H.J. Lu
2015-12-17 13:42 ` Uros Bizjak
0 siblings, 1 reply; 11+ messages in thread
From: H.J. Lu @ 2015-12-17 13:00 UTC (permalink / raw)
To: Uros Bizjak; +Cc: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 1137 bytes --]
On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>> Since sibcall never returns, we can only use call-clobbered register
>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>> be properly restored.
>>
>> Tested on x86-64 with -m32. OK for trunk?
>
> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
> class, and register_no_elim_operand predicate should be used with "U"
> constraint. Also, please introduce new predicate, similar to how
> GOT_memory_operand is defined and handled.
>
Here is the updated patch. There is a predicate already,
sibcall_memory_operand. It allows any registers to
be as GOT base, which is the root of our problem.
This patch removes GOT slot from it and handles
sibcall over GOT slot with *sibcall_GOT_32 and
*sibcall_value_GOT_32 patterns. Since I need to
expose constraints on GOT base register to RA,
I have to use 2 operands, GOT base and function
symbol, to describe sibcall over 32-bit GOT slot.
OK for master if there is no regression.
Thanks.
--
H.J.
[-- Attachment #2: 0001-Use-call-clobbered-register-for-sibcall-via-GOT.patch --]
[-- Type: text/x-patch, Size: 8201 bytes --]
From e055e1ea71353897aa7ce4b38a5186c8b64ddc7c Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 16 Dec 2015 12:34:57 -0800
Subject: [PATCH] Use call-clobbered register for sibcall via GOT
Since sibcall never returns, we can only use call-clobbered register
as GOT base. Otherwise, callee-saved register used as GOT base won't
be properly restored.
gcc/
PR target/68937
* config/i386/i386.c (ix86_function_ok_for_sibcall): Count
call via GOT slot as indirect call.
* config/i386/i386.md (*sibcall_GOT_32): New pattern.
(*sibcall_value_GOT_32): Likewise.
* config/i386/predicates.md (sibcall_memory_operand): Remove
GOT slot.
gcc/testsuite/
PR target/68937
* gcc.target/i386/pr68937-1.c: New test.
* gcc.target/i386/pr68937-2.c: Likewise.
* gcc.target/i386/pr68937-3.c: Likewise.
* gcc.target/i386/pr68937-4.c: Likewise.
* gcc.target/i386/pr68937-5.c: Likewise.
---
gcc/config/i386/i386.c | 4 ++-
gcc/config/i386/i386.md | 43 +++++++++++++++++++++++++++++++
gcc/config/i386/predicates.md | 10 +++----
gcc/testsuite/gcc.target/i386/pr68937-1.c | 13 ++++++++++
gcc/testsuite/gcc.target/i386/pr68937-2.c | 13 ++++++++++
gcc/testsuite/gcc.target/i386/pr68937-3.c | 13 ++++++++++
gcc/testsuite/gcc.target/i386/pr68937-4.c | 13 ++++++++++
gcc/testsuite/gcc.target/i386/pr68937-5.c | 9 +++++++
8 files changed, 111 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-5.c
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index cecea24..0e2bec3 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6723,8 +6723,10 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
/* If this call is indirect, we'll need to be able to use a
call-clobbered register for the address of the target function.
Make sure that all such registers are not used for passing
- parameters. Note that DLLIMPORT functions are indirect. */
+ parameters. Note that DLLIMPORT functions and call via GOT
+ slot are indirect. */
if (!decl
+ || (flag_pic && !flag_plt)
|| (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
{
/* Check if regparm >= 3 since arg_reg_available is set to
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 49b2216..7c62586 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -11865,6 +11865,27 @@
"* return ix86_output_call_insn (insn, operands[0]);"
[(set_attr "type" "call")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_GOT_32"
+ [(call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 0 "register_no_elim_operand" "U")
+ (const:SI
+ (unspec:SI [(match_operand:SI 1 "symbol_operand")]
+ UNSPEC_GOT)))))
+ (match_operand 2))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, operands[1]),
+ UNSPEC_GOT);
+ fnaddr = gen_rtx_CONST (Pmode, fnaddr);
+ fnaddr = gen_rtx_PLUS (Pmode, operands[0], fnaddr);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "call")])
+
(define_insn "*sibcall"
[(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "UBsBz"))
(match_operand 1))]
@@ -12042,6 +12063,28 @@
"* return ix86_output_call_insn (insn, operands[1]);"
[(set_attr "type" "callv")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_value_GOT_32"
+ [(set (match_operand 0)
+ (call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 1 "register_no_elim_operand" "U")
+ (const:SI
+ (unspec:SI [(match_operand:SI 2 "symbol_operand")]
+ UNSPEC_GOT)))))
+ (match_operand 3)))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, operands[2]),
+ UNSPEC_GOT);
+ fnaddr = gen_rtx_CONST (Pmode, fnaddr);
+ fnaddr = gen_rtx_PLUS (Pmode, operands[1], fnaddr);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "callv")])
+
(define_insn "*sibcall_value"
[(set (match_operand 0)
(call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "UBsBz"))
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
index 8bdd5d8..006bb2c 100644
--- a/gcc/config/i386/predicates.md
+++ b/gcc/config/i386/predicates.md
@@ -597,14 +597,12 @@
(match_operand 0 "memory_operand"))))
;; Return true if OP is a memory operands that can be used in sibcalls.
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base. Don't allow GOT slot here. Handle sibcall over GOT
+;; slot with *sibcall_GOT_32 and *sibcall_value_GOT_32 patterns.
(define_predicate "sibcall_memory_operand"
(and (match_operand 0 "memory_operand")
- (match_test "CONSTANT_P (XEXP (op, 0))
- || (GET_CODE (XEXP (op, 0)) == PLUS
- && REG_P (XEXP (XEXP (op, 0), 0))
- && GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
- && GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
- && XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
+ (match_test "CONSTANT_P (XEXP (op, 0))")))
;; Test for a valid operand for a call instruction.
;; Allow constant call address operands in Pmode only.
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-1.c b/gcc/testsuite/gcc.target/i386/pr68937-1.c
new file mode 100644
index 0000000..897856b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-1.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int);
+
+void
+foo (int b)
+{
+ bar (b);
+ bar (b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-2.c b/gcc/testsuite/gcc.target/i386/pr68937-2.c
new file mode 100644
index 0000000..257f4e2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-2.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int);
+
+void
+foo (int a, int b)
+{
+ bar (a, b);
+ bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-3.c b/gcc/testsuite/gcc.target/i386/pr68937-3.c
new file mode 100644
index 0000000..6d8e40f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-3.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int, int);
+
+void
+foo (int a, int b, int c)
+{
+ bar (a, b, c);
+ bar (a, b, c);
+}
+
+/* { dg-final { scan-assembler-not "jmp\[ \t\]*.bar@GOT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-4.c b/gcc/testsuite/gcc.target/i386/pr68937-4.c
new file mode 100644
index 0000000..9c19956
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-4.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern int bar (int, int);
+
+int
+foo (int a, int b)
+{
+ (void) bar (a, b);
+ return bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-5.c b/gcc/testsuite/gcc.target/i386/pr68937-5.c
new file mode 100644
index 0000000..f7e3ec5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-5.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target { *-*-linux* } } } */
+/* { dg-options "-O2 -fpic -fno-plt -funroll-loops" } */
+
+extern void *f();
+void dmi_scan_machine(void) {
+ char *p = f(), *q;
+ for (q = p; q < p + 10; q++)
+ ;
+}
--
2.5.0
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-17 13:00 ` H.J. Lu
@ 2015-12-17 13:42 ` Uros Bizjak
2015-12-17 15:50 ` H.J. Lu
0 siblings, 1 reply; 11+ messages in thread
From: Uros Bizjak @ 2015-12-17 13:42 UTC (permalink / raw)
To: H.J. Lu; +Cc: gcc-patches
On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>> Since sibcall never returns, we can only use call-clobbered register
>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>> be properly restored.
>>>
>>> Tested on x86-64 with -m32. OK for trunk?
>>
>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>> class, and register_no_elim_operand predicate should be used with "U"
>> constraint. Also, please introduce new predicate, similar to how
>> GOT_memory_operand is defined and handled.
>>
>
> Here is the updated patch. There is a predicate already,
> sibcall_memory_operand. It allows any registers to
> be as GOT base, which is the root of our problem.
> This patch removes GOT slot from it and handles
> sibcall over GOT slot with *sibcall_GOT_32 and
> *sibcall_value_GOT_32 patterns. Since I need to
> expose constraints on GOT base register to RA,
> I have to use 2 operands, GOT base and function
> symbol, to describe sibcall over 32-bit GOT slot.
Please use
(mem:SI (plus:SI
(match_operand:SI 0 "register_no_elim_operand" "U")
(match_operand:SI 1 "GOT32_symbol_operand")))
...
to avoid manual rebuild of the operand.
Uros.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-17 13:42 ` Uros Bizjak
@ 2015-12-17 15:50 ` H.J. Lu
2015-12-17 16:12 ` H.J. Lu
0 siblings, 1 reply; 11+ messages in thread
From: H.J. Lu @ 2015-12-17 15:50 UTC (permalink / raw)
To: Uros Bizjak; +Cc: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 1531 bytes --]
On Thu, Dec 17, 2015 at 5:42 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>>> Since sibcall never returns, we can only use call-clobbered register
>>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>>> be properly restored.
>>>>
>>>> Tested on x86-64 with -m32. OK for trunk?
>>>
>>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>>> class, and register_no_elim_operand predicate should be used with "U"
>>> constraint. Also, please introduce new predicate, similar to how
>>> GOT_memory_operand is defined and handled.
>>>
>>
>> Here is the updated patch. There is a predicate already,
>> sibcall_memory_operand. It allows any registers to
>> be as GOT base, which is the root of our problem.
>> This patch removes GOT slot from it and handles
>> sibcall over GOT slot with *sibcall_GOT_32 and
>> *sibcall_value_GOT_32 patterns. Since I need to
>> expose constraints on GOT base register to RA,
>> I have to use 2 operands, GOT base and function
>> symbol, to describe sibcall over 32-bit GOT slot.
>
> Please use
>
> (mem:SI (plus:SI
> (match_operand:SI 0 "register_no_elim_operand" "U")
> (match_operand:SI 1 "GOT32_symbol_operand")))
> ...
>
> to avoid manual rebuild of the operand.
>
Is this OK?
Thanks.
--
H.J.
[-- Attachment #2: 0001-Use-call-clobbered-register-for-sibcall-via-GOT.patch --]
[-- Type: text/x-patch, Size: 8375 bytes --]
From 9a5818415f9de92454ee555e8d8c3bd675fe30dd Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 16 Dec 2015 12:34:57 -0800
Subject: [PATCH] Use call-clobbered register for sibcall via GOT
Since sibcall never returns, we can only use call-clobbered register
as GOT base. Otherwise, callee-saved register used as GOT base won't
be properly restored.
gcc/
PR target/68937
* config/i386/i386.c (ix86_function_ok_for_sibcall): Count
call via GOT slot as indirect call.
* config/i386/i386.md (*sibcall_GOT_32): New pattern.
(*sibcall_value_GOT_32): Likewise.
* config/i386/predicates.md (sibcall_memory_operand): Remove
GOT slot.
(GOT32_symbol_operand): New predicate.
gcc/testsuite/
PR target/68937
* gcc.target/i386/pr68937-1.c: New test.
* gcc.target/i386/pr68937-2.c: Likewise.
* gcc.target/i386/pr68937-3.c: Likewise.
* gcc.target/i386/pr68937-4.c: Likewise.
* gcc.target/i386/pr68937-5.c: Likewise.
---
gcc/config/i386/i386.c | 4 +++-
gcc/config/i386/i386.md | 33 +++++++++++++++++++++++++++++++
gcc/config/i386/predicates.md | 16 +++++++++------
gcc/testsuite/gcc.target/i386/pr68937-1.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-2.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-3.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-4.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-5.c | 9 +++++++++
8 files changed, 107 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-5.c
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index cecea24..0e2bec3 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6723,8 +6723,10 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
/* If this call is indirect, we'll need to be able to use a
call-clobbered register for the address of the target function.
Make sure that all such registers are not used for passing
- parameters. Note that DLLIMPORT functions are indirect. */
+ parameters. Note that DLLIMPORT functions and call via GOT
+ slot are indirect. */
if (!decl
+ || (flag_pic && !flag_plt)
|| (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
{
/* Check if regparm >= 3 since arg_reg_available is set to
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 49b2216..6ab8eaa 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -11865,6 +11865,22 @@
"* return ix86_output_call_insn (insn, operands[0]);"
[(set_attr "type" "call")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_GOT_32"
+ [(call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 0 "register_no_elim_operand" "U")
+ (match_operand:SI 1 "GOT32_symbol_operand"))))
+ (match_operand 2))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_PLUS (Pmode, operands[0], operands[1]);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "call")])
+
(define_insn "*sibcall"
[(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "UBsBz"))
(match_operand 1))]
@@ -12042,6 +12058,23 @@
"* return ix86_output_call_insn (insn, operands[1]);"
[(set_attr "type" "callv")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_value_GOT_32"
+ [(set (match_operand 0)
+ (call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 1 "register_no_elim_operand" "U")
+ (match_operand:SI 2 "GOT32_symbol_operand"))))
+ (match_operand 3)))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_PLUS (Pmode, operands[1], operands[2]);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "callv")])
+
(define_insn "*sibcall_value"
[(set (match_operand 0)
(call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "UBsBz"))
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
index 8bdd5d8..e750e96 100644
--- a/gcc/config/i386/predicates.md
+++ b/gcc/config/i386/predicates.md
@@ -597,14 +597,12 @@
(match_operand 0 "memory_operand"))))
;; Return true if OP is a memory operands that can be used in sibcalls.
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base. Don't allow GOT slot here. Handle sibcall over GOT
+;; slot with *sibcall_GOT_32 and *sibcall_value_GOT_32 patterns.
(define_predicate "sibcall_memory_operand"
(and (match_operand 0 "memory_operand")
- (match_test "CONSTANT_P (XEXP (op, 0))
- || (GET_CODE (XEXP (op, 0)) == PLUS
- && REG_P (XEXP (XEXP (op, 0), 0))
- && GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
- && GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
- && XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
+ (match_test "CONSTANT_P (XEXP (op, 0))")))
;; Test for a valid operand for a call instruction.
;; Allow constant call address operands in Pmode only.
@@ -633,6 +631,12 @@
&& XINT (XEXP (op, 0), 1) == UNSPEC_GOTPCREL);
})
+;; Return true if OP is a 32-bit GOT symbol operand.
+(define_predicate "GOT32_symbol_operand"
+ (match_test "GET_CODE (op) == CONST
+ && GET_CODE (XEXP (op, 0)) == UNSPEC
+ && XINT (XEXP (op, 0), 1) == UNSPEC_GOT"))
+
;; Match exactly zero.
(define_predicate "const0_operand"
(match_code "const_int,const_wide_int,const_double,const_vector")
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-1.c b/gcc/testsuite/gcc.target/i386/pr68937-1.c
new file mode 100644
index 0000000..897856b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-1.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int);
+
+void
+foo (int b)
+{
+ bar (b);
+ bar (b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-2.c b/gcc/testsuite/gcc.target/i386/pr68937-2.c
new file mode 100644
index 0000000..257f4e2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-2.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int);
+
+void
+foo (int a, int b)
+{
+ bar (a, b);
+ bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-3.c b/gcc/testsuite/gcc.target/i386/pr68937-3.c
new file mode 100644
index 0000000..6d8e40f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-3.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int, int);
+
+void
+foo (int a, int b, int c)
+{
+ bar (a, b, c);
+ bar (a, b, c);
+}
+
+/* { dg-final { scan-assembler-not "jmp\[ \t\]*.bar@GOT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-4.c b/gcc/testsuite/gcc.target/i386/pr68937-4.c
new file mode 100644
index 0000000..9c19956
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-4.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern int bar (int, int);
+
+int
+foo (int a, int b)
+{
+ (void) bar (a, b);
+ return bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-5.c b/gcc/testsuite/gcc.target/i386/pr68937-5.c
new file mode 100644
index 0000000..f7e3ec5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-5.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target { *-*-linux* } } } */
+/* { dg-options "-O2 -fpic -fno-plt -funroll-loops" } */
+
+extern void *f();
+void dmi_scan_machine(void) {
+ char *p = f(), *q;
+ for (q = p; q < p + 10; q++)
+ ;
+}
--
2.5.0
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-17 15:50 ` H.J. Lu
@ 2015-12-17 16:12 ` H.J. Lu
2015-12-17 18:09 ` H.J. Lu
0 siblings, 1 reply; 11+ messages in thread
From: H.J. Lu @ 2015-12-17 16:12 UTC (permalink / raw)
To: Uros Bizjak; +Cc: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 1753 bytes --]
On Thu, Dec 17, 2015 at 7:50 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 5:42 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>>>> Since sibcall never returns, we can only use call-clobbered register
>>>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>>>> be properly restored.
>>>>>
>>>>> Tested on x86-64 with -m32. OK for trunk?
>>>>
>>>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>>>> class, and register_no_elim_operand predicate should be used with "U"
>>>> constraint. Also, please introduce new predicate, similar to how
>>>> GOT_memory_operand is defined and handled.
>>>>
>>>
>>> Here is the updated patch. There is a predicate already,
>>> sibcall_memory_operand. It allows any registers to
>>> be as GOT base, which is the root of our problem.
>>> This patch removes GOT slot from it and handles
>>> sibcall over GOT slot with *sibcall_GOT_32 and
>>> *sibcall_value_GOT_32 patterns. Since I need to
>>> expose constraints on GOT base register to RA,
>>> I have to use 2 operands, GOT base and function
>>> symbol, to describe sibcall over 32-bit GOT slot.
>>
>> Please use
>>
>> (mem:SI (plus:SI
>> (match_operand:SI 0 "register_no_elim_operand" "U")
>> (match_operand:SI 1 "GOT32_symbol_operand")))
>> ...
>>
>> to avoid manual rebuild of the operand.
>>
>
> Is this OK?
>
An updated patch to allow sibcall_memory_operand for RTL
expansion. OK for trunk if there is no regression?
Thanks.
--
H.J.
[-- Attachment #2: 0001-Use-call-clobbered-register-for-sibcall-via-GOT.patch --]
[-- Type: text/x-patch, Size: 8666 bytes --]
From dffd3a70b9788174f9b279ff27bf72dbc2384659 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 16 Dec 2015 12:34:57 -0800
Subject: [PATCH] Use call-clobbered register for sibcall via GOT
Since sibcall never returns, we can only use call-clobbered register as
GOT base. Otherwise, callee-saved register used as GOT base won't be
properly restored. sibcall_memory_operand is changed to allow 32-bit
GOT slot only with pseudo register as GOT base for RTL expansion. 2
new patterns, *sibcall_GOT_32 and *sibcall_value_GOT_32, are added to
expose GOT base register to register allocator so that call-clobbered
register will be used for GOT base.
gcc/
PR target/68937
* config/i386/i386.c (ix86_function_ok_for_sibcall): Count
call via GOT slot as indirect call.
* config/i386/i386.md (*sibcall_GOT_32): New pattern.
(*sibcall_value_GOT_32): Likewise.
* config/i386/predicates.md (sibcall_memory_operand): Allow
32-bit GOT slot only with pseudo register as GOT base.
(GOT32_symbol_operand): New predicate.
gcc/testsuite/
PR target/68937
* gcc.target/i386/pr68937-1.c: New test.
* gcc.target/i386/pr68937-2.c: Likewise.
* gcc.target/i386/pr68937-3.c: Likewise.
* gcc.target/i386/pr68937-4.c: Likewise.
* gcc.target/i386/pr68937-5.c: Likewise.
---
gcc/config/i386/i386.c | 4 +++-
gcc/config/i386/i386.md | 33 +++++++++++++++++++++++++++++++
gcc/config/i386/predicates.md | 12 +++++++++++
gcc/testsuite/gcc.target/i386/pr68937-1.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-2.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-3.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-4.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-5.c | 9 +++++++++
8 files changed, 109 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-5.c
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index cecea24..0e2bec3 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6723,8 +6723,10 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
/* If this call is indirect, we'll need to be able to use a
call-clobbered register for the address of the target function.
Make sure that all such registers are not used for passing
- parameters. Note that DLLIMPORT functions are indirect. */
+ parameters. Note that DLLIMPORT functions and call via GOT
+ slot are indirect. */
if (!decl
+ || (flag_pic && !flag_plt)
|| (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
{
/* Check if regparm >= 3 since arg_reg_available is set to
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 49b2216..6ab8eaa 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -11865,6 +11865,22 @@
"* return ix86_output_call_insn (insn, operands[0]);"
[(set_attr "type" "call")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_GOT_32"
+ [(call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 0 "register_no_elim_operand" "U")
+ (match_operand:SI 1 "GOT32_symbol_operand"))))
+ (match_operand 2))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_PLUS (Pmode, operands[0], operands[1]);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "call")])
+
(define_insn "*sibcall"
[(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "UBsBz"))
(match_operand 1))]
@@ -12042,6 +12058,23 @@
"* return ix86_output_call_insn (insn, operands[1]);"
[(set_attr "type" "callv")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_value_GOT_32"
+ [(set (match_operand 0)
+ (call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 1 "register_no_elim_operand" "U")
+ (match_operand:SI 2 "GOT32_symbol_operand"))))
+ (match_operand 3)))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_PLUS (Pmode, operands[1], operands[2]);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "callv")])
+
(define_insn "*sibcall_value"
[(set (match_operand 0)
(call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "UBsBz"))
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
index 8bdd5d8..f33a53a 100644
--- a/gcc/config/i386/predicates.md
+++ b/gcc/config/i386/predicates.md
@@ -597,11 +597,17 @@
(match_operand 0 "memory_operand"))))
;; Return true if OP is a memory operands that can be used in sibcalls.
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base. Allow GOT slot here only with pseudo register as GOT
+;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
+;; and *sibcall_value_GOT_32 patterns.
(define_predicate "sibcall_memory_operand"
(and (match_operand 0 "memory_operand")
(match_test "CONSTANT_P (XEXP (op, 0))
|| (GET_CODE (XEXP (op, 0)) == PLUS
&& REG_P (XEXP (XEXP (op, 0), 0))
+ && (REGNO (XEXP (XEXP (op, 0), 0))
+ >= FIRST_PSEUDO_REGISTER)
&& GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
&& GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
&& XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
@@ -633,6 +639,12 @@
&& XINT (XEXP (op, 0), 1) == UNSPEC_GOTPCREL);
})
+;; Return true if OP is a 32-bit GOT symbol operand.
+(define_predicate "GOT32_symbol_operand"
+ (match_test "GET_CODE (op) == CONST
+ && GET_CODE (XEXP (op, 0)) == UNSPEC
+ && XINT (XEXP (op, 0), 1) == UNSPEC_GOT"))
+
;; Match exactly zero.
(define_predicate "const0_operand"
(match_code "const_int,const_wide_int,const_double,const_vector")
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-1.c b/gcc/testsuite/gcc.target/i386/pr68937-1.c
new file mode 100644
index 0000000..897856b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-1.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int);
+
+void
+foo (int b)
+{
+ bar (b);
+ bar (b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-2.c b/gcc/testsuite/gcc.target/i386/pr68937-2.c
new file mode 100644
index 0000000..257f4e2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-2.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int);
+
+void
+foo (int a, int b)
+{
+ bar (a, b);
+ bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-3.c b/gcc/testsuite/gcc.target/i386/pr68937-3.c
new file mode 100644
index 0000000..6d8e40f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-3.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int, int);
+
+void
+foo (int a, int b, int c)
+{
+ bar (a, b, c);
+ bar (a, b, c);
+}
+
+/* { dg-final { scan-assembler-not "jmp\[ \t\]*.bar@GOT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-4.c b/gcc/testsuite/gcc.target/i386/pr68937-4.c
new file mode 100644
index 0000000..9c19956
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-4.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern int bar (int, int);
+
+int
+foo (int a, int b)
+{
+ (void) bar (a, b);
+ return bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-5.c b/gcc/testsuite/gcc.target/i386/pr68937-5.c
new file mode 100644
index 0000000..f7e3ec5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-5.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target { *-*-linux* } } } */
+/* { dg-options "-O2 -fpic -fno-plt -funroll-loops" } */
+
+extern void *f();
+void dmi_scan_machine(void) {
+ char *p = f(), *q;
+ for (q = p; q < p + 10; q++)
+ ;
+}
--
2.5.0
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-17 16:12 ` H.J. Lu
@ 2015-12-17 18:09 ` H.J. Lu
2015-12-17 21:21 ` Uros Bizjak
0 siblings, 1 reply; 11+ messages in thread
From: H.J. Lu @ 2015-12-17 18:09 UTC (permalink / raw)
To: Uros Bizjak; +Cc: gcc-patches
On Thu, Dec 17, 2015 at 8:11 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 7:50 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 5:42 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>> On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>>>>> Since sibcall never returns, we can only use call-clobbered register
>>>>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>>>>> be properly restored.
>>>>>>
>>>>>> Tested on x86-64 with -m32. OK for trunk?
>>>>>
>>>>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>>>>> class, and register_no_elim_operand predicate should be used with "U"
>>>>> constraint. Also, please introduce new predicate, similar to how
>>>>> GOT_memory_operand is defined and handled.
>>>>>
>>>>
>>>> Here is the updated patch. There is a predicate already,
>>>> sibcall_memory_operand. It allows any registers to
>>>> be as GOT base, which is the root of our problem.
>>>> This patch removes GOT slot from it and handles
>>>> sibcall over GOT slot with *sibcall_GOT_32 and
>>>> *sibcall_value_GOT_32 patterns. Since I need to
>>>> expose constraints on GOT base register to RA,
>>>> I have to use 2 operands, GOT base and function
>>>> symbol, to describe sibcall over 32-bit GOT slot.
>>>
>>> Please use
>>>
>>> (mem:SI (plus:SI
>>> (match_operand:SI 0 "register_no_elim_operand" "U")
>>> (match_operand:SI 1 "GOT32_symbol_operand")))
>>> ...
>>>
>>> to avoid manual rebuild of the operand.
>>>
>>
>> Is this OK?
>>
>
> An updated patch to allow sibcall_memory_operand for RTL
> expansion. OK for trunk if there is no regression?
>
There is no regressions on x86-64 with -m32. OK for trunk?
--
H.J.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-17 18:09 ` H.J. Lu
@ 2015-12-17 21:21 ` Uros Bizjak
2015-12-17 21:59 ` H.J. Lu
0 siblings, 1 reply; 11+ messages in thread
From: Uros Bizjak @ 2015-12-17 21:21 UTC (permalink / raw)
To: H.J. Lu; +Cc: gcc-patches
On Thu, Dec 17, 2015 at 7:09 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 8:11 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 7:50 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, Dec 17, 2015 at 5:42 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>> On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>>>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>>>>>> Since sibcall never returns, we can only use call-clobbered register
>>>>>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>>>>>> be properly restored.
>>>>>>>
>>>>>>> Tested on x86-64 with -m32. OK for trunk?
>>>>>>
>>>>>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>>>>>> class, and register_no_elim_operand predicate should be used with "U"
>>>>>> constraint. Also, please introduce new predicate, similar to how
>>>>>> GOT_memory_operand is defined and handled.
>>>>>>
>>>>>
>>>>> Here is the updated patch. There is a predicate already,
>>>>> sibcall_memory_operand. It allows any registers to
>>>>> be as GOT base, which is the root of our problem.
>>>>> This patch removes GOT slot from it and handles
>>>>> sibcall over GOT slot with *sibcall_GOT_32 and
>>>>> *sibcall_value_GOT_32 patterns. Since I need to
>>>>> expose constraints on GOT base register to RA,
>>>>> I have to use 2 operands, GOT base and function
>>>>> symbol, to describe sibcall over 32-bit GOT slot.
>>>>
>>>> Please use
>>>>
>>>> (mem:SI (plus:SI
>>>> (match_operand:SI 0 "register_no_elim_operand" "U")
>>>> (match_operand:SI 1 "GOT32_symbol_operand")))
>>>> ...
>>>>
>>>> to avoid manual rebuild of the operand.
>>>>
>>>
>>> Is this OK?
>>>
>>
>> An updated patch to allow sibcall_memory_operand for RTL
>> expansion. OK for trunk if there is no regression?
>>
>
> There is no regressions on x86-64 with -m32. OK for trunk?
OK for mainline, with a following change:
@@ -597,11 +597,17 @@
(match_operand 0 "memory_operand"))))
;; Return true if OP is a memory operands that can be used in sibcalls.
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base. Allow GOT slot here only with pseudo register as GOT
+;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
+;; and *sibcall_value_GOT_32 patterns.
(define_predicate "sibcall_memory_operand"
(and (match_operand 0 "memory_operand")
(match_test "CONSTANT_P (XEXP (op, 0))
|| (GET_CODE (XEXP (op, 0)) == PLUS
&& REG_P (XEXP (XEXP (op, 0), 0))
+ && (REGNO (XEXP (XEXP (op, 0), 0))
+ >= FIRST_PSEUDO_REGISTER)
&& GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
&& GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
&& XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
You can use (!HARD_REGISTER_NUM_P (...) || call_used_regs[...]) here.
Call-used hard regs are still allowed here.
Can you please also rewrite this horrible match_test as a block of C
code using GOT32_symbol_operand predicate?
Thanks,
Uros.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-17 21:21 ` Uros Bizjak
@ 2015-12-17 21:59 ` H.J. Lu
2015-12-18 0:55 ` H.J. Lu
0 siblings, 1 reply; 11+ messages in thread
From: H.J. Lu @ 2015-12-17 21:59 UTC (permalink / raw)
To: Uros Bizjak; +Cc: gcc-patches
On Thu, Dec 17, 2015 at 1:21 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 7:09 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 8:11 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, Dec 17, 2015 at 7:50 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>> On Thu, Dec 17, 2015 at 5:42 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>>> On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>>>>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>>>>>>> Since sibcall never returns, we can only use call-clobbered register
>>>>>>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>>>>>>> be properly restored.
>>>>>>>>
>>>>>>>> Tested on x86-64 with -m32. OK for trunk?
>>>>>>>
>>>>>>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>>>>>>> class, and register_no_elim_operand predicate should be used with "U"
>>>>>>> constraint. Also, please introduce new predicate, similar to how
>>>>>>> GOT_memory_operand is defined and handled.
>>>>>>>
>>>>>>
>>>>>> Here is the updated patch. There is a predicate already,
>>>>>> sibcall_memory_operand. It allows any registers to
>>>>>> be as GOT base, which is the root of our problem.
>>>>>> This patch removes GOT slot from it and handles
>>>>>> sibcall over GOT slot with *sibcall_GOT_32 and
>>>>>> *sibcall_value_GOT_32 patterns. Since I need to
>>>>>> expose constraints on GOT base register to RA,
>>>>>> I have to use 2 operands, GOT base and function
>>>>>> symbol, to describe sibcall over 32-bit GOT slot.
>>>>>
>>>>> Please use
>>>>>
>>>>> (mem:SI (plus:SI
>>>>> (match_operand:SI 0 "register_no_elim_operand" "U")
>>>>> (match_operand:SI 1 "GOT32_symbol_operand")))
>>>>> ...
>>>>>
>>>>> to avoid manual rebuild of the operand.
>>>>>
>>>>
>>>> Is this OK?
>>>>
>>>
>>> An updated patch to allow sibcall_memory_operand for RTL
>>> expansion. OK for trunk if there is no regression?
>>>
>>
>> There is no regressions on x86-64 with -m32. OK for trunk?
>
> OK for mainline, with a following change:
>
> @@ -597,11 +597,17 @@
> (match_operand 0 "memory_operand"))))
>
> ;; Return true if OP is a memory operands that can be used in sibcalls.
> +;; Since sibcall never returns, we can only use call-clobbered register
> +;; as GOT base. Allow GOT slot here only with pseudo register as GOT
> +;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
> +;; and *sibcall_value_GOT_32 patterns.
> (define_predicate "sibcall_memory_operand"
> (and (match_operand 0 "memory_operand")
> (match_test "CONSTANT_P (XEXP (op, 0))
> || (GET_CODE (XEXP (op, 0)) == PLUS
> && REG_P (XEXP (XEXP (op, 0), 0))
> + && (REGNO (XEXP (XEXP (op, 0), 0))
> + >= FIRST_PSEUDO_REGISTER)
> && GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
> && GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
> && XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
>
> You can use (!HARD_REGISTER_NUM_P (...) || call_used_regs[...]) here.
> Call-used hard regs are still allowed here.
>
> Can you please also rewrite this horrible match_test as a block of C
> code using GOT32_symbol_operand predicate?
>
I am retesting the patch with
;; Return true if OP is a memory operands that can be used in sibcalls.
;; Since sibcall never returns, we can only use call-clobbered register
;; as GOT base. Allow GOT slot here only with pseudo register as GOT
;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
;; and *sibcall_value_GOT_32 patterns.
(define_predicate "sibcall_memory_operand"
(match_operand 0 "memory_operand")
{
op = XEXP (op, 0);
if (CONSTANT_P (op))
return true;
if (GET_CODE (op) == PLUS && REG_P (XEXP (op, 0)))
{
int regno = REGNO (XEXP (op, 0));
if (!HARD_REGISTER_NUM_P (regno) || call_used_regs[regno])
{
op = XEXP (op, 1);
if (GOT32_symbol_operand (op, VOIDmode))
return true;
}
}
return false;
})
I will check it in if there is no regression.
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-17 21:59 ` H.J. Lu
@ 2015-12-18 0:55 ` H.J. Lu
2015-12-19 16:19 ` Uros Bizjak
0 siblings, 1 reply; 11+ messages in thread
From: H.J. Lu @ 2015-12-18 0:55 UTC (permalink / raw)
To: Uros Bizjak; +Cc: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 5984 bytes --]
On Thu, Dec 17, 2015 at 1:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 1:21 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 7:09 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, Dec 17, 2015 at 8:11 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>> On Thu, Dec 17, 2015 at 7:50 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>> On Thu, Dec 17, 2015 at 5:42 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>>>> On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>>> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>>>>>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>>>>>>>> Since sibcall never returns, we can only use call-clobbered register
>>>>>>>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>>>>>>>> be properly restored.
>>>>>>>>>
>>>>>>>>> Tested on x86-64 with -m32. OK for trunk?
>>>>>>>>
>>>>>>>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>>>>>>>> class, and register_no_elim_operand predicate should be used with "U"
>>>>>>>> constraint. Also, please introduce new predicate, similar to how
>>>>>>>> GOT_memory_operand is defined and handled.
>>>>>>>>
>>>>>>>
>>>>>>> Here is the updated patch. There is a predicate already,
>>>>>>> sibcall_memory_operand. It allows any registers to
>>>>>>> be as GOT base, which is the root of our problem.
>>>>>>> This patch removes GOT slot from it and handles
>>>>>>> sibcall over GOT slot with *sibcall_GOT_32 and
>>>>>>> *sibcall_value_GOT_32 patterns. Since I need to
>>>>>>> expose constraints on GOT base register to RA,
>>>>>>> I have to use 2 operands, GOT base and function
>>>>>>> symbol, to describe sibcall over 32-bit GOT slot.
>>>>>>
>>>>>> Please use
>>>>>>
>>>>>> (mem:SI (plus:SI
>>>>>> (match_operand:SI 0 "register_no_elim_operand" "U")
>>>>>> (match_operand:SI 1 "GOT32_symbol_operand")))
>>>>>> ...
>>>>>>
>>>>>> to avoid manual rebuild of the operand.
>>>>>>
>>>>>
>>>>> Is this OK?
>>>>>
>>>>
>>>> An updated patch to allow sibcall_memory_operand for RTL
>>>> expansion. OK for trunk if there is no regression?
>>>>
>>>
>>> There is no regressions on x86-64 with -m32. OK for trunk?
>>
>> OK for mainline, with a following change:
>>
>> @@ -597,11 +597,17 @@
>> (match_operand 0 "memory_operand"))))
>>
>> ;; Return true if OP is a memory operands that can be used in sibcalls.
>> +;; Since sibcall never returns, we can only use call-clobbered register
>> +;; as GOT base. Allow GOT slot here only with pseudo register as GOT
>> +;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
>> +;; and *sibcall_value_GOT_32 patterns.
>> (define_predicate "sibcall_memory_operand"
>> (and (match_operand 0 "memory_operand")
>> (match_test "CONSTANT_P (XEXP (op, 0))
>> || (GET_CODE (XEXP (op, 0)) == PLUS
>> && REG_P (XEXP (XEXP (op, 0), 0))
>> + && (REGNO (XEXP (XEXP (op, 0), 0))
>> + >= FIRST_PSEUDO_REGISTER)
>> && GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
>> && GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
>> && XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
>>
>> You can use (!HARD_REGISTER_NUM_P (...) || call_used_regs[...]) here.
>> Call-used hard regs are still allowed here.
>>
>> Can you please also rewrite this horrible match_test as a block of C
>> code using GOT32_symbol_operand predicate?
>>
>
> I am retesting the patch with
>
> ;; Return true if OP is a memory operands that can be used in sibcalls.
> ;; Since sibcall never returns, we can only use call-clobbered register
> ;; as GOT base. Allow GOT slot here only with pseudo register as GOT
> ;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
> ;; and *sibcall_value_GOT_32 patterns.
> (define_predicate "sibcall_memory_operand"
> (match_operand 0 "memory_operand")
> {
> op = XEXP (op, 0);
> if (CONSTANT_P (op))
> return true;
> if (GET_CODE (op) == PLUS && REG_P (XEXP (op, 0)))
> {
> int regno = REGNO (XEXP (op, 0));
> if (!HARD_REGISTER_NUM_P (regno) || call_used_regs[regno])
> {
> op = XEXP (op, 1);
> if (GOT32_symbol_operand (op, VOIDmode))
> return true;
> }
> }
> return false;
> })
>
>
> I will check it in if there is no regression.
>
There is no regression. But I missed sibcall to local function
with -O2 -fPIC -m32 -fno-plt -mregparm=3:
extern void bar (int, int, int) __attribute__((visibility("hidden")));
void
foo (int a, int b, int c)
{
bar (a, b, c);
bar (a, b, c);
}
It doesn't need GOT. This patch fixes it.
iff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 0e2bec3..691915f9 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6657,6 +6657,7 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
{
tree type, decl_or_type;
rtx a, b;
+ bool bind_global = decl && !targetm.binds_local_p (decl);
/* If we are generating position-independent code, we cannot sibcall
optimize direct calls to global functions, as the PLT requires
@@ -6665,7 +6666,7 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
&& !TARGET_64BIT
&& flag_pic
&& flag_plt
- && decl && !targetm.binds_local_p (decl))
+ && bind_global)
return false;
/* If we need to align the outgoing stack, then sibcalling would
@@ -6726,7 +6727,7 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
parameters. Note that DLLIMPORT functions and call via GOT
slot are indirect. */
if (!decl
- || (flag_pic && !flag_plt)
+ || (bind_global && flag_pic && !flag_plt)
|| (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
{
/* Check if regparm >= 3 since arg_reg_available is set to
Here is the complete patch with a testcase. OK for trunk?
Thanks.
--
H.J.
[-- Attachment #2: 0001-Use-call-clobbered-register-for-sibcall-via-GOT.patch --]
[-- Type: text/x-patch, Size: 10583 bytes --]
From e4a7e066a8cdbb638fc5e1312c01f1043a2679fc Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 16 Dec 2015 12:34:57 -0800
Subject: [PATCH] Use call-clobbered register for sibcall via GOT
Since sibcall never returns, we can only use call-clobbered register as
GOT base. Otherwise, callee-saved register used as GOT base won't be
properly restored. sibcall_memory_operand is changed to allow 32-bit
GOT slot only with pseudo register as GOT base for RTL expansion. 2
new patterns, *sibcall_GOT_32 and *sibcall_value_GOT_32, are added to
expose GOT base register to register allocator so that call-clobbered
register will be used for GOT base.
gcc/
PR target/68937
* config/i386/i386.c (ix86_function_ok_for_sibcall): Count
call to global function via GOT slot as indirect call.
* config/i386/i386.md (*sibcall_GOT_32): New pattern.
(*sibcall_value_GOT_32): Likewise.
* config/i386/predicates.md (sibcall_memory_operand): Rewrite.
Allow 32-bit GOT slot only with pseudo register as GOT base.
(GOT32_symbol_operand): New predicate.
gcc/testsuite/
PR target/68937
* gcc.target/i386/pr68937-1.c: New test.
* gcc.target/i386/pr68937-2.c: Likewise.
* gcc.target/i386/pr68937-3.c: Likewise.
* gcc.target/i386/pr68937-4.c: Likewise.
* gcc.target/i386/pr68937-5.c: Likewise.
* gcc.target/i386/pr68937-6.c: Likewise.
---
gcc/config/i386/i386.c | 7 +++++--
gcc/config/i386/i386.md | 33 ++++++++++++++++++++++++++++++
gcc/config/i386/predicates.md | 34 ++++++++++++++++++++++++-------
gcc/testsuite/gcc.target/i386/pr68937-1.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-2.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-3.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-4.c | 13 ++++++++++++
gcc/testsuite/gcc.target/i386/pr68937-5.c | 9 ++++++++
gcc/testsuite/gcc.target/i386/pr68937-6.c | 16 +++++++++++++++
9 files changed, 142 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-5.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr68937-6.c
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index cecea24..f5d23d9 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6657,6 +6657,7 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
{
tree type, decl_or_type;
rtx a, b;
+ bool bind_global = decl && !targetm.binds_local_p (decl);
/* If we are generating position-independent code, we cannot sibcall
optimize direct calls to global functions, as the PLT requires
@@ -6665,7 +6666,7 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
&& !TARGET_64BIT
&& flag_pic
&& flag_plt
- && decl && !targetm.binds_local_p (decl))
+ && bind_global)
return false;
/* If we need to align the outgoing stack, then sibcalling would
@@ -6723,8 +6724,10 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
/* If this call is indirect, we'll need to be able to use a
call-clobbered register for the address of the target function.
Make sure that all such registers are not used for passing
- parameters. Note that DLLIMPORT functions are indirect. */
+ parameters. Note that DLLIMPORT functions and call to global
+ function via GOT slot are indirect. */
if (!decl
+ || (bind_global && flag_pic && !flag_plt)
|| (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
{
/* Check if regparm >= 3 since arg_reg_available is set to
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 49b2216..6ab8eaa 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -11865,6 +11865,22 @@
"* return ix86_output_call_insn (insn, operands[0]);"
[(set_attr "type" "call")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_GOT_32"
+ [(call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 0 "register_no_elim_operand" "U")
+ (match_operand:SI 1 "GOT32_symbol_operand"))))
+ (match_operand 2))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_PLUS (Pmode, operands[0], operands[1]);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "call")])
+
(define_insn "*sibcall"
[(call (mem:QI (match_operand:W 0 "sibcall_insn_operand" "UBsBz"))
(match_operand 1))]
@@ -12042,6 +12058,23 @@
"* return ix86_output_call_insn (insn, operands[1]);"
[(set_attr "type" "callv")])
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base.
+(define_insn "*sibcall_value_GOT_32"
+ [(set (match_operand 0)
+ (call (mem:QI
+ (mem:SI (plus:SI
+ (match_operand:SI 1 "register_no_elim_operand" "U")
+ (match_operand:SI 2 "GOT32_symbol_operand"))))
+ (match_operand 3)))]
+ "!TARGET_MACHO && !TARGET_64BIT && SIBLING_CALL_P (insn)"
+{
+ rtx fnaddr = gen_rtx_PLUS (Pmode, operands[1], operands[2]);
+ fnaddr = gen_const_mem (Pmode, fnaddr);
+ return ix86_output_call_insn (insn, fnaddr);
+}
+ [(set_attr "type" "callv")])
+
(define_insn "*sibcall_value"
[(set (match_operand 0)
(call (mem:QI (match_operand:W 1 "sibcall_insn_operand" "UBsBz"))
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
index 8bdd5d8..96d946c 100644
--- a/gcc/config/i386/predicates.md
+++ b/gcc/config/i386/predicates.md
@@ -597,14 +597,28 @@
(match_operand 0 "memory_operand"))))
;; Return true if OP is a memory operands that can be used in sibcalls.
+;; Since sibcall never returns, we can only use call-clobbered register
+;; as GOT base. Allow GOT slot here only with pseudo register as GOT
+;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
+;; and *sibcall_value_GOT_32 patterns.
(define_predicate "sibcall_memory_operand"
- (and (match_operand 0 "memory_operand")
- (match_test "CONSTANT_P (XEXP (op, 0))
- || (GET_CODE (XEXP (op, 0)) == PLUS
- && REG_P (XEXP (XEXP (op, 0), 0))
- && GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
- && GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
- && XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
+ (match_operand 0 "memory_operand")
+{
+ op = XEXP (op, 0);
+ if (CONSTANT_P (op))
+ return true;
+ if (GET_CODE (op) == PLUS && REG_P (XEXP (op, 0)))
+ {
+ int regno = REGNO (XEXP (op, 0));
+ if (!HARD_REGISTER_NUM_P (regno) || call_used_regs[regno])
+ {
+ op = XEXP (op, 1);
+ if (GOT32_symbol_operand (op, VOIDmode))
+ return true;
+ }
+ }
+ return false;
+})
;; Test for a valid operand for a call instruction.
;; Allow constant call address operands in Pmode only.
@@ -633,6 +647,12 @@
&& XINT (XEXP (op, 0), 1) == UNSPEC_GOTPCREL);
})
+;; Return true if OP is a 32-bit GOT symbol operand.
+(define_predicate "GOT32_symbol_operand"
+ (match_test "GET_CODE (op) == CONST
+ && GET_CODE (XEXP (op, 0)) == UNSPEC
+ && XINT (XEXP (op, 0), 1) == UNSPEC_GOT"))
+
;; Match exactly zero.
(define_predicate "const0_operand"
(match_code "const_int,const_wide_int,const_double,const_vector")
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-1.c b/gcc/testsuite/gcc.target/i386/pr68937-1.c
new file mode 100644
index 0000000..897856b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-1.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int);
+
+void
+foo (int b)
+{
+ bar (b);
+ bar (b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-2.c b/gcc/testsuite/gcc.target/i386/pr68937-2.c
new file mode 100644
index 0000000..257f4e2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-2.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int);
+
+void
+foo (int a, int b)
+{
+ bar (a, b);
+ bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-3.c b/gcc/testsuite/gcc.target/i386/pr68937-3.c
new file mode 100644
index 0000000..6d8e40f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-3.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void bar (int, int, int);
+
+void
+foo (int a, int b, int c)
+{
+ bar (a, b, c);
+ bar (a, b, c);
+}
+
+/* { dg-final { scan-assembler-not "jmp\[ \t\]*.bar@GOT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-4.c b/gcc/testsuite/gcc.target/i386/pr68937-4.c
new file mode 100644
index 0000000..9c19956
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-4.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern int bar (int, int);
+
+int
+foo (int a, int b)
+{
+ (void) bar (a, b);
+ return bar (a, b);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*.bar@GOT\\(%e(a|c|d)x\\)" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-5.c b/gcc/testsuite/gcc.target/i386/pr68937-5.c
new file mode 100644
index 0000000..f7e3ec5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-5.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target { *-*-linux* } } } */
+/* { dg-options "-O2 -fpic -fno-plt -funroll-loops" } */
+
+extern void *f();
+void dmi_scan_machine(void) {
+ char *p = f(), *q;
+ for (q = p; q < p + 10; q++)
+ ;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr68937-6.c b/gcc/testsuite/gcc.target/i386/pr68937-6.c
new file mode 100644
index 0000000..406ce28
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68937-6.c
@@ -0,0 +1,16 @@
+/* { dg-do compile { target { *-*-linux* && ia32 } } } */
+/* { dg-options "-O2 -fpic -fno-plt -mregparm=3" } */
+
+extern void foo (int, int, int);
+extern void bar (int, int, int) __attribute__((visibility("hidden")));
+
+void
+foo (int a, int b, int c)
+{
+ foo (a, b, c);
+ bar (a, b, c);
+ foo (a, b, c);
+ bar (a, b, c);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]bar" } } */
--
2.5.0
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall
2015-12-18 0:55 ` H.J. Lu
@ 2015-12-19 16:19 ` Uros Bizjak
0 siblings, 0 replies; 11+ messages in thread
From: Uros Bizjak @ 2015-12-19 16:19 UTC (permalink / raw)
To: H.J. Lu; +Cc: gcc-patches, Jakub Jelinek
On Fri, Dec 18, 2015 at 1:55 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 1:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 1:21 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>> On Thu, Dec 17, 2015 at 7:09 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>> On Thu, Dec 17, 2015 at 8:11 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>> On Thu, Dec 17, 2015 at 7:50 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>> On Thu, Dec 17, 2015 at 5:42 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>>>>> On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>>>> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
>>>>>>>>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>>>>>>>>> Since sibcall never returns, we can only use call-clobbered register
>>>>>>>>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>>>>>>>>> be properly restored.
>>>>>>>>>>
>>>>>>>>>> Tested on x86-64 with -m32. OK for trunk?
>>>>>>>>>
>>>>>>>>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>>>>>>>>> class, and register_no_elim_operand predicate should be used with "U"
>>>>>>>>> constraint. Also, please introduce new predicate, similar to how
>>>>>>>>> GOT_memory_operand is defined and handled.
>>>>>>>>>
>>>>>>>>
>>>>>>>> Here is the updated patch. There is a predicate already,
>>>>>>>> sibcall_memory_operand. It allows any registers to
>>>>>>>> be as GOT base, which is the root of our problem.
>>>>>>>> This patch removes GOT slot from it and handles
>>>>>>>> sibcall over GOT slot with *sibcall_GOT_32 and
>>>>>>>> *sibcall_value_GOT_32 patterns. Since I need to
>>>>>>>> expose constraints on GOT base register to RA,
>>>>>>>> I have to use 2 operands, GOT base and function
>>>>>>>> symbol, to describe sibcall over 32-bit GOT slot.
>>>>>>>
>>>>>>> Please use
>>>>>>>
>>>>>>> (mem:SI (plus:SI
>>>>>>> (match_operand:SI 0 "register_no_elim_operand" "U")
>>>>>>> (match_operand:SI 1 "GOT32_symbol_operand")))
>>>>>>> ...
>>>>>>>
>>>>>>> to avoid manual rebuild of the operand.
>>>>>>>
>>>>>>
>>>>>> Is this OK?
>>>>>>
>>>>>
>>>>> An updated patch to allow sibcall_memory_operand for RTL
>>>>> expansion. OK for trunk if there is no regression?
>>>>>
>>>>
>>>> There is no regressions on x86-64 with -m32. OK for trunk?
>>>
>>> OK for mainline, with a following change:
>>>
>>> @@ -597,11 +597,17 @@
>>> (match_operand 0 "memory_operand"))))
>>>
>>> ;; Return true if OP is a memory operands that can be used in sibcalls.
>>> +;; Since sibcall never returns, we can only use call-clobbered register
>>> +;; as GOT base. Allow GOT slot here only with pseudo register as GOT
>>> +;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
>>> +;; and *sibcall_value_GOT_32 patterns.
>>> (define_predicate "sibcall_memory_operand"
>>> (and (match_operand 0 "memory_operand")
>>> (match_test "CONSTANT_P (XEXP (op, 0))
>>> || (GET_CODE (XEXP (op, 0)) == PLUS
>>> && REG_P (XEXP (XEXP (op, 0), 0))
>>> + && (REGNO (XEXP (XEXP (op, 0), 0))
>>> + >= FIRST_PSEUDO_REGISTER)
>>> && GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
>>> && GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
>>> && XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
>>>
>>> You can use (!HARD_REGISTER_NUM_P (...) || call_used_regs[...]) here.
>>> Call-used hard regs are still allowed here.
>>>
>>> Can you please also rewrite this horrible match_test as a block of C
>>> code using GOT32_symbol_operand predicate?
>>>
>>
>> I am retesting the patch with
>>
>> ;; Return true if OP is a memory operands that can be used in sibcalls.
>> ;; Since sibcall never returns, we can only use call-clobbered register
>> ;; as GOT base. Allow GOT slot here only with pseudo register as GOT
>> ;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
>> ;; and *sibcall_value_GOT_32 patterns.
>> (define_predicate "sibcall_memory_operand"
>> (match_operand 0 "memory_operand")
>> {
>> op = XEXP (op, 0);
>> if (CONSTANT_P (op))
>> return true;
>> if (GET_CODE (op) == PLUS && REG_P (XEXP (op, 0)))
>> {
>> int regno = REGNO (XEXP (op, 0));
>> if (!HARD_REGISTER_NUM_P (regno) || call_used_regs[regno])
>> {
>> op = XEXP (op, 1);
>> if (GOT32_symbol_operand (op, VOIDmode))
>> return true;
>> }
>> }
>> return false;
>> })
>>
>>
>> I will check it in if there is no regression.
>>
>
> There is no regression. But I missed sibcall to local function
> with -O2 -fPIC -m32 -fno-plt -mregparm=3:
>
> extern void bar (int, int, int) __attribute__((visibility("hidden")));
>
> void
> foo (int a, int b, int c)
> {
> bar (a, b, c);
> bar (a, b, c);
> }
>
> It doesn't need GOT. This patch fixes it.
>
> iff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 0e2bec3..691915f9 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -6657,6 +6657,7 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
> {
> tree type, decl_or_type;
> rtx a, b;
> + bool bind_global = decl && !targetm.binds_local_p (decl);
>
> /* If we are generating position-independent code, we cannot sibcall
> optimize direct calls to global functions, as the PLT requires
> @@ -6665,7 +6666,7 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
> && !TARGET_64BIT
> && flag_pic
> && flag_plt
> - && decl && !targetm.binds_local_p (decl))
> + && bind_global)
> return false;
>
> /* If we need to align the outgoing stack, then sibcalling would
> @@ -6726,7 +6727,7 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
> parameters. Note that DLLIMPORT functions and call via GOT
> slot are indirect. */
> if (!decl
> - || (flag_pic && !flag_plt)
> + || (bind_global && flag_pic && !flag_plt)
> || (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
> {
> /* Check if regparm >= 3 since arg_reg_available is set to
>
> Here is the complete patch with a testcase. OK for trunk?
LGTM, but please allow Jakub (CC'd) a couple of days for his eventual objection.
Otherwise, OK for mainline after this period.
Uros.
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2015-12-19 16:19 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-12-16 23:29 [PATCH] PR target/68937: i686: -fno-plt produces wrong code (maybe only with tailcall H.J. Lu
2015-12-17 10:04 ` Uros Bizjak
2015-12-17 13:00 ` H.J. Lu
2015-12-17 13:42 ` Uros Bizjak
2015-12-17 15:50 ` H.J. Lu
2015-12-17 16:12 ` H.J. Lu
2015-12-17 18:09 ` H.J. Lu
2015-12-17 21:21 ` Uros Bizjak
2015-12-17 21:59 ` H.J. Lu
2015-12-18 0:55 ` H.J. Lu
2015-12-19 16:19 ` Uros Bizjak
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