[gcc(refs/vendors/redhat/heads/gcc-8-branch)] aarch64: Fix bootstrap with old binutils [PR93053]

[gcc(refs/vendors/redhat/heads/gcc-8-branch)] aarch64: Fix bootstrap with old binutils [PR93053]

[Jakub Jelinek]

https://gcc.gnu.org/g:e33188b820cacb065d0ca2580d301e95e6ebf3d4

commit e33188b820cacb065d0ca2580d301e95e6ebf3d4
Author: Andre Vieira <andre.simoesdiasvieira@arm.com>
Date:   Thu Apr 16 10:16:18 2020 +0100

    aarch64: Fix bootstrap with old binutils [PR93053]
    
    As reported in the PR, GCC 10 (and also 9.3.1 but not 9.3.0) fails to build
    when using older binutils which lack LSE support, because those instructions
    are used in libgcc.
    Thanks to Kyrylo's hint, the following patches (hopefully) allow it to build
    even with older binutils by using .inst directive if LSE support isn't
    available in the assembler.
    
    2020-04-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
    
            Backport from mainline
            2020-04-15  Jakub Jelinek  <jakub@redhat.com>
    
            PR target/93053
            * configure.ac (LIBGCC_CHECK_AS_LSE): Add HAVE_AS_LSE checking.
            * config/aarch64/lse.S: Include auto-target.h, if HAVE_AS_LSE
            is not defined, use just .arch armv8-a.
            (B, M, N, OPN): Define.
            (COMMENT): New .macro.
            (CAS, CASP, SWP, LDOP): Use .inst directive if HAVE_AS_LSE is not
            defined.  Otherwise, move the operands right after the glue? and
            comment out operands where the macros are used.
            * configure: Regenerated.
            * config.in: Regenerated.

Diff:
---
 libgcc/ChangeLog            | 17 ++++++++++++++
 libgcc/config.in            |  3 +++
 libgcc/config/aarch64/lse.S | 57 ++++++++++++++++++++++++++++++++++++++-------
 libgcc/configure            | 40 +++++++++++++++++++++++++++++++
 libgcc/configure.ac         | 19 +++++++++++++++
 5 files changed, 128 insertions(+), 8 deletions(-)

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 9387872c3ca..9cea69a0b9b 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,20 @@
+2020-04-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
+
+	Backport from mainline
+	2020-04-15  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/93053
+	* configure.ac (LIBGCC_CHECK_AS_LSE): Add HAVE_AS_LSE checking.
+	* config/aarch64/lse.S: Include auto-target.h, if HAVE_AS_LSE
+	is not defined, use just .arch armv8-a.
+	(B, M, N, OPN): Define.
+	(COMMENT): New .macro.
+	(CAS, CASP, SWP, LDOP): Use .inst directive if HAVE_AS_LSE is not
+	defined.  Otherwise, move the operands right after the glue? and
+	comment out operands where the macros are used.
+	* configure: Regenerated.
+	* config.in: Regenerated.
+
 2020-04-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
 
 	Backport from mainline
diff --git a/libgcc/config.in b/libgcc/config.in
index 59a3d8daf52..5be5321d258 100644
--- a/libgcc/config.in
+++ b/libgcc/config.in
@@ -10,6 +10,9 @@
    */
 #undef HAVE_AS_CFI_SECTIONS
 
+/* Define to 1 if the assembler supports LSE. */
+#undef HAVE_AS_LSE
+
 /* Define to 1 if the target assembler supports thread-local storage. */
 #undef HAVE_CC_TLS
 
diff --git a/libgcc/config/aarch64/lse.S b/libgcc/config/aarch64/lse.S
index c7979382ad7..f7f1c19587b 100644
--- a/libgcc/config/aarch64/lse.S
+++ b/libgcc/config/aarch64/lse.S
@@ -48,8 +48,14 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  * separately to minimize code size.
  */
 
+#include "auto-target.h"
+
 /* Tell the assembler to accept LSE instructions.  */
+#ifdef HAVE_AS_LSE
 	.arch armv8-a+lse
+#else
+	.arch armv8-a
+#endif
 
 /* Declare the symbol gating the LSE implementations.  */
 	.hidden	__aarch64_have_lse_atomics
@@ -58,12 +64,19 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #if SIZE == 1
 # define S     b
 # define UXT   uxtb
+# define B     0x00000000
 #elif SIZE == 2
 # define S     h
 # define UXT   uxth
+# define B     0x40000000
 #elif SIZE == 4 || SIZE == 8 || SIZE == 16
 # define S
 # define UXT   mov
+# if SIZE == 4
+#  define B    0x80000000
+# elif SIZE == 8
+#  define B    0xc0000000
+# endif
 #else
 # error
 #endif
@@ -72,18 +85,26 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 # define SUFF  _relax
 # define A
 # define L
+# define M     0x000000
+# define N     0x000000
 #elif MODEL == 2
 # define SUFF  _acq
 # define A     a
 # define L
+# define M     0x400000
+# define N     0x800000
 #elif MODEL == 3
 # define SUFF  _rel
 # define A
 # define L     l
+# define M     0x008000
+# define N     0x400000
 #elif MODEL == 4
 # define SUFF  _acq_rel
 # define A     a
 # define L     l
+# define M     0x408000
+# define N     0xc00000
 #else
 # error
 #endif
@@ -144,9 +165,13 @@ STARTFN	NAME(cas)
 	JUMP_IF_NOT_LSE	8f
 
 #if SIZE < 16
-#define CAS	glue4(cas, A, L, S)
+#ifdef HAVE_AS_LSE
+# define CAS	glue4(cas, A, L, S)	s(0), s(1), [x2]
+#else
+# define CAS	.inst 0x08a07c41 + B + M
+#endif
 
-	CAS		s(0), s(1), [x2]
+	CAS		/* s(0), s(1), [x2] */
 	ret
 
 8:	UXT		s(tmp0), s(0)
@@ -160,9 +185,13 @@ STARTFN	NAME(cas)
 #else
 #define LDXP	glue3(ld, A, xp)
 #define STXP	glue3(st, L, xp)
-#define CASP	glue3(casp, A, L)
+#ifdef HAVE_AS_LSE
+# define CASP	glue3(casp, A, L)	x0, x1, x2, x3, [x4]
+#else
+# define CASP	.inst 0x48207c82 + M
+#endif
 
-	CASP		x0, x1, x2, x3, [x4]
+	CASP		/* x0, x1, x2, x3, [x4] */
 	ret
 
 8:	mov		x(tmp0), x0
@@ -181,12 +210,16 @@ ENDFN	NAME(cas)
 #endif
 
 #ifdef L_swp
-#define SWP	glue4(swp, A, L, S)
+#ifdef HAVE_AS_LSE
+# define SWP	glue4(swp, A, L, S)	s(0), s(0), [x1]
+#else
+# define SWP	.inst 0x38208020 + B + N
+#endif
 
 STARTFN	NAME(swp)
 	JUMP_IF_NOT_LSE	8f
 
-	SWP		s(0), s(0), [x1]
+	SWP		/* s(0), s(0), [x1] */
 	ret
 
 8:	mov		s(tmp0), s(0)
@@ -204,24 +237,32 @@ ENDFN	NAME(swp)
 #ifdef L_ldadd
 #define LDNM	ldadd
 #define OP	add
+#define OPN	0x0000
 #elif defined(L_ldclr)
 #define LDNM	ldclr
 #define OP	bic
+#define OPN	0x1000
 #elif defined(L_ldeor)
 #define LDNM	ldeor
 #define OP	eor
+#define OPN	0x2000
 #elif defined(L_ldset)
 #define LDNM	ldset
 #define OP	orr
+#define OPN	0x3000
 #else
 #error
 #endif
-#define LDOP	glue4(LDNM, A, L, S)
+#ifdef HAVE_AS_LSE
+# define LDOP	glue4(LDNM, A, L, S)	s(0), s(0), [x1]
+#else
+# define LDOP	.inst 0x38200020 + OPN + B + N
+#endif
 
 STARTFN	NAME(LDNM)
 	JUMP_IF_NOT_LSE	8f
 
-	LDOP		s(0), s(0), [x1]
+	LDOP		/* s(0), s(0), [x1] */
 	ret
 
 8:	mov		s(tmp0), s(0)
diff --git a/libgcc/configure b/libgcc/configure
index 7962cd9b87e..aac5e5fb6a7 100755
--- a/libgcc/configure
+++ b/libgcc/configure
@@ -5385,6 +5385,46 @@ $as_echo "#define HAVE_AS_AVX 1" >>confdefs.h
   ;;
 esac
 
+
+
+case "${target}" in
+aarch64*-*-*)
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if the assembler supports LSE" >&5
+$as_echo_n "checking if the assembler supports LSE... " >&6; }
+if ${libgcc_cv_as_lse+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+			asm(".arch armv8-a+lse\n\tcas w0, w1, [x2]");
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  libgcc_cv_as_lse=yes
+else
+  libgcc_cv_as_lse=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libgcc_cv_as_lse" >&5
+$as_echo "$libgcc_cv_as_lse" >&6; }
+  if test x$libgcc_cv_as_lse = xyes; then
+
+$as_echo "#define HAVE_AS_LSE 1" >>confdefs.h
+
+  fi
+  ;;
+esac
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for init priority support" >&5
 $as_echo_n "checking for init priority support... " >&6; }
 if test "${libgcc_cv_init_priority+set}" = set; then :
diff --git a/libgcc/configure.ac b/libgcc/configure.ac
index b18519171c7..5f0a63ce2f0 100644
--- a/libgcc/configure.ac
+++ b/libgcc/configure.ac
@@ -543,6 +543,25 @@ i[[34567]]86-*-* | x86_64-*-*)
 esac])
 LIBGCC_CHECK_AS_AVX
 
+dnl Check if as supports LSE instructions.
+AC_DEFUN([LIBGCC_CHECK_AS_LSE], [
+case "${target}" in
+aarch64*-*-*)
+  AC_CACHE_CHECK([if the assembler supports LSE], libgcc_cv_as_lse, [
+    AC_TRY_COMPILE([],
+changequote(,)dnl
+			asm(".arch armv8-a+lse\n\tcas w0, w1, [x2]");
+changequote([,])dnl
+		       ,
+		   [libgcc_cv_as_lse=yes], [libgcc_cv_as_lse=no])
+  ])
+  if test x$libgcc_cv_as_lse = xyes; then
+    AC_DEFINE(HAVE_AS_LSE, 1, [Define to 1 if the assembler supports LSE.])
+  fi
+  ;;
+esac])
+LIBGCC_CHECK_AS_LSE
+
 dnl Check if as supports RTM instructions.
 AC_CACHE_CHECK(for init priority support, libgcc_cv_init_priority, [
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,