On Fri, Mar 12, 2021 at 8:37 AM Uros Bizjak <ubiz...@gmail.com> wrote:
>
> On Fri, Mar 12, 2021 at 2:20 PM H.J. Lu <hjl.to...@gmail.com> wrote:
> >
> > On Thu, Mar 11, 2021 at 11:21 PM Uros Bizjak <ubiz...@gmail.com> wrote:
> > >
> > > On Thu, Mar 11, 2021 at 11:22 PM H.J. Lu <hjl.to...@gmail.com> wrote:
> > > >
> > > > 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_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.
> > > > ---
> > > > gcc/config/i386/i386.c | 33 +++++++++++++++++++++--
> > > > gcc/testsuite/gcc.target/i386/pr99530-1.c | 11 ++++++++
> > > > gcc/testsuite/gcc.target/i386/pr99530-2.c | 11 ++++++++
> > > > gcc/testsuite/gcc.target/i386/pr99530-3.c | 11 ++++++++
> > > > gcc/testsuite/gcc.target/i386/pr99530-4.c | 11 ++++++++
> > > > gcc/testsuite/gcc.target/i386/pr99530-5.c | 11 ++++++++
> > > > gcc/testsuite/gcc.target/i386/pr99530-6.c | 11 ++++++++
> > > > 7 files changed, 97 insertions(+), 2 deletions(-)
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-1.c
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-2.c
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-3.c
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-4.c
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-5.c
> > > > create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-6.c
> > > >
> > > > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> > > > index 2603333f87b..8733fcecf65 100644
> > > > --- a/gcc/config/i386/i386.c
> > > > +++ b/gcc/config/i386/i386.c
> > > > @@ -12701,7 +12701,8 @@ 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 +13446,35 @@ ix86_print_operand (FILE *file, rtx x, int
> > > > code)
> > > > x = const0_rtx;
> > > > }
> > > >
> > > > - if (code != 'P' && code != 'p')
> > > > + if (code == 'P')
> > > > + {
> > > > + if (current_output_insn == NULL_RTX
> > > > + && (TARGET_64BIT || (!flag_pic && HAVE_AS_IX86_GOT32X))
> > > > + && !TARGET_PECOFF
> > > > + && !TARGET_MACHO
> > > > + && ix86_cmodel != CM_LARGE
> > > > + && ix86_cmodel != CM_LARGE_PIC
> > > > + && GET_CODE (x) == SYMBOL_REF
> > > > + && SYMBOL_REF_FUNCTION_P (x)
> > > > + && (!flag_plt
> > > > + || (SYMBOL_REF_DECL (x)
> > > > + && lookup_attribute ("noplt",
> > > > + DECL_ATTRIBUTES
> > > > (SYMBOL_REF_DECL (x)))))
> > > > + && !SYMBOL_REF_LOCAL_P (x))
> > > > + {
> > > > + /* For inline assembly statement, load function address
> > > > + from GOT with 'P' operand modifier to avoid PLT.
> > > > + NB: This works only with call or jmp. */
> > > > + const char *xasm;
> > > > + if (TARGET_64BIT)
> > > > + xasm = "{*%p0@GOTPCREL(%%rip)|[QWORD PTR
> > > > %p0@GOTPCREL[rip]]}";
> > > > + else
> > > > + xasm = "{*%p0@GOT|[DWORD PTR %p0@GOT]}";
> > > > + output_asm_insn (xasm, &x);
> > > > + return;
> > >
> > > This should be handled in output_pic_addr_const.
> > >
> >
> > call/jmp are special and are handled by ix86_output_call_insn,
> > not output_pic_addr_const.
>
> I see, the call_insn is output using output_asm_insn, which I think is
> not appropriate in ix86_print_operand. Probably you should introduce a
> new helper function and output a GOTPCREL reloc there. Something like
> x86_print_operand with 'A' code, calling output_addr_const and
> appending @GOTPCREL. Perhaps some parts of ix86_print_opreands can be
> used instead.
Done. Here is the updated patch. Tested on Linux/x86-64. OK for master?
Thanks.
--
H.J.
From 0dc17859846944d9e4aef31e70821415002a7801 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.to...@gmail.com>
Date: Thu, 11 Mar 2021 06:48:24 -0800
Subject: [PATCH v3] x86: Update 'P' operand modifier for -fno-plt
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.
---
gcc/config/i386/i386.c | 32 +++++++++++++++++++----
gcc/testsuite/gcc.target/i386/pr99530-1.c | 11 ++++++++
gcc/testsuite/gcc.target/i386/pr99530-2.c | 11 ++++++++
gcc/testsuite/gcc.target/i386/pr99530-3.c | 11 ++++++++
gcc/testsuite/gcc.target/i386/pr99530-4.c | 11 ++++++++
gcc/testsuite/gcc.target/i386/pr99530-5.c | 11 ++++++++
gcc/testsuite/gcc.target/i386/pr99530-6.c | 11 ++++++++
7 files changed, 93 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-5.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr99530-6.c
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 2603333f87b..247ad1b150d 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -10265,15 +10265,19 @@ 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: For inline assembly statement, allow PIC/non-PIC in 64-bit mode
+ and in 32-bit mode, only non-PIC is allowed since we don't have
+ PIC register at call site. Otherwise, only PIC is allowed. */
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 || current_output_insn == NULL_RTX)
&& ix86_cmodel != CM_LARGE
+ && ix86_cmodel != CM_LARGE_PIC
&& GET_CODE (x) == SYMBOL_REF
&& SYMBOL_REF_FUNCTION_P (x)
&& (!flag_plt
@@ -12701,7 +12705,8 @@ 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 +13450,24 @@ 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.
+ NB: This works only with call or jmp. */
+ 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))
{
diff --git a/gcc/testsuite/gcc.target/i386/pr99530-1.c b/gcc/testsuite/gcc.target/i386/pr99530-1.c
new file mode 100644
index 00000000000..080d7cc9399
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr99530-1.c
@@ -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));
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr99530-2.c b/gcc/testsuite/gcc.target/i386/pr99530-2.c
new file mode 100644
index 00000000000..9808957d624
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr99530-2.c
@@ -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));
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr99530-3.c b/gcc/testsuite/gcc.target/i386/pr99530-3.c
new file mode 100644
index 00000000000..22fe81b25f2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr99530-3.c
@@ -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));
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr99530-4.c b/gcc/testsuite/gcc.target/i386/pr99530-4.c
new file mode 100644
index 00000000000..aba0b5d7892
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr99530-4.c
@@ -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));
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr99530-5.c b/gcc/testsuite/gcc.target/i386/pr99530-5.c
new file mode 100644
index 00000000000..02c5799d273
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr99530-5.c
@@ -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));
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr99530-6.c b/gcc/testsuite/gcc.target/i386/pr99530-6.c
new file mode 100644
index 00000000000..0dfdd3752f7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr99530-6.c
@@ -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));
+}
--
2.30.2
