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x86: Update 'P' operand modifier for -fno-plt

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Update 'P' operand modifier for -fno-plt to support inline assembly
statements.  In 64-bit, we can always load function address with
@GOTPCREL.  In 32-bit, we load function address with @GOT only for
non-PIC since PIC register may not be available at call site.

gcc/

	PR target/99504
	* config/i386/i386.c (ix86_force_load_from_GOT_p): Support
	inline assembly statements.
	(ix86_print_operand): Update 'P' handling for -fno-plt.

gcc/testsuite/

	PR target/99504
	* gcc.target/i386/pr99530-1.c: New test.
	* gcc.target/i386/pr99530-2.c: Likewise.
	* gcc.target/i386/pr99530-3.c: Likewise.
	* gcc.target/i386/pr99530-4.c: Likewise.
	* gcc.target/i386/pr99530-5.c: Likewise.
	* gcc.target/i386/pr99530-6.c: Likewise.
This commit is contained in:
H.J. Lu 2021-03-11 06:48:24 -08:00
parent 39916ceab4
commit adf14bdbc1
7 changed files with 93 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
gcc/config/i386/i386.c
View file

@ -10265,15 +10265,20 @@ darwin_local_data_pic (rtx disp)
&& XINT (disp, 1) == UNSPEC_MACHOPIC_OFFSET);
}
/* True if operand X should be loaded from GOT. */
/* True if the function symbol operand X should be loaded from GOT.
NB: In 32-bit mode, only non-PIC is allowed in inline assembly
statements, since a PIC register could not be available at the
call site. */
bool
ix86_force_load_from_GOT_p (rtx x)
{
return ((TARGET_64BIT || HAVE_AS_IX86_GOT32X)
return ((TARGET_64BIT || (!flag_pic && HAVE_AS_IX86_GOT32X))
&& !TARGET_PECOFF && !TARGET_MACHO
&& !flag_pic
&& (!flag_pic || this_is_asm_operands)
&& ix86_cmodel != CM_LARGE
&& ix86_cmodel != CM_LARGE_PIC
&& GET_CODE (x) == SYMBOL_REF
&& SYMBOL_REF_FUNCTION_P (x)
&& (!flag_plt
@ -12701,7 +12706,8 @@ print_reg (rtx x, int code, FILE *file)
y -- print "st(0)" instead of "st" as a register.
d -- print duplicated register operand for AVX instruction.
D -- print condition for SSE cmp instruction.
P -- if PIC, print an @PLT suffix.
P -- if PIC, print an @PLT suffix. For -fno-plt, load function
address from GOT.
p -- print raw symbol name.
X -- don't print any sort of PIC '@' suffix for a symbol.
& -- print some in-use local-dynamic symbol name.
@ -13445,7 +13451,23 @@ ix86_print_operand (FILE *file, rtx x, int code)
x = const0_rtx;
}
if (code != 'P' && code != 'p')
if (code == 'P')
{
if (ix86_force_load_from_GOT_p (x))
{
/* For inline assembly statement, load function address
from GOT with 'P' operand modifier to avoid PLT. */
x = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, x),
(TARGET_64BIT
? UNSPEC_GOTPCREL
: UNSPEC_GOT));
x = gen_rtx_CONST (Pmode, x);
x = gen_const_mem (Pmode, x);
ix86_print_operand (file, x, 'A');
return;
}
}
else if (code != 'p')
{
if (CONST_INT_P (x))
{

11
gcc/testsuite/gcc.target/i386/pr99530-1.c Normal file
View file

@ -0,0 +1,11 @@
/* { dg-do compile { target { i?86-*-linux* x86_64-*-linux* } } } */
/* { dg-require-effective-target lp64 } */
/* { dg-options "-O2 -fpic -mcmodel=large -fno-plt" } */
/* { dg-final { scan-assembler-not "foo@GOTPCREL" } } */
extern void foo (void);
void
bar (void)
{
asm ("call %P0" : : "X" (foo));
}

11
gcc/testsuite/gcc.target/i386/pr99530-2.c Normal file
View file

@ -0,0 +1,11 @@
/* { dg-do compile { target { i?86-*-linux* x86_64-*-linux* } } } */
/* { dg-require-effective-target lp64 } */
/* { dg-options "-O2 -fno-pic -mcmodel=large -fno-plt" } */
/* { dg-final { scan-assembler-not "foo@GOTPCREL" } } */
extern void foo (void);
void
bar (void)
{
asm ("call %P0" : : "X" (foo));
}

11
gcc/testsuite/gcc.target/i386/pr99530-3.c Normal file
View file

@ -0,0 +1,11 @@
/* { dg-do compile { target { i?86-*-linux* x86_64-*-linux* } } } */
/* { dg-options "-O2 -fno-pic -fno-plt" } */
/* { dg-final { scan-assembler "call\[ \t\]+\[*\]foo@GOTPCREL" { target { ! ia32 } } } } */
/* { dg-final { scan-assembler "call\[ \t\]+\[*\]foo@GOT" { target { ia32 && got32x_reloc } } } } */
extern void foo (void);
void
bar (void)
{
asm ("call %P0" : : "X" (foo));
}

11
gcc/testsuite/gcc.target/i386/pr99530-4.c Normal file
View file

@ -0,0 +1,11 @@
/* { dg-do compile { target { i?86-*-linux* x86_64-*-linux* } } } */
/* { dg-options "-O2 -fpic -fno-plt" } */
/* { dg-final { scan-assembler "call\[ \t\]+\[*\]foo@GOTPCREL" { target { ! ia32 } } } } */
/* { dg-final { scan-assembler-not "foo@GOT" { target { ia32 } } } } */
extern void foo (void);
void
bar (void)
{
asm ("call %P0" : : "X" (foo));
}

11
gcc/testsuite/gcc.target/i386/pr99530-5.c Normal file
View file

@ -0,0 +1,11 @@
/* { dg-do compile { target { i?86-*-linux* x86_64-*-linux* } } } */
/* { dg-options "-O2 -fno-pic" } */
/* { dg-final { scan-assembler "call\[ \t\]+\[*\]foo@GOTPCREL" { target { ! ia32 } } } } */
/* { dg-final { scan-assembler "call\[ \t\]+\[*\]foo@GOT" { target { ia32 && got32x_reloc } } } } */
extern void foo (void) __attribute__ ((noplt));
void
bar (void)
{
asm ("call %P0" : : "X" (foo));
}

11
gcc/testsuite/gcc.target/i386/pr99530-6.c Normal file
View file

@ -0,0 +1,11 @@
/* { dg-do compile { target { i?86-*-linux* x86_64-*-linux* } } } */
/* { dg-options "-O2 -fpic" } */
/* { dg-final { scan-assembler "call\[ \t\]+\[*\]foo@GOTPCREL" { target { ! ia32 } } } } */
/* { dg-final { scan-assembler-not "foo@GOT" { target { ia32 } } } } */
extern void foo (void) __attribute__ ((noplt));
void
bar (void)
{
asm ("call %P0" : : "X" (foo));
}