Guard declarations of 'sve_{vq,vl}_from_{vl,vq}' macros on Aarch64 (and unbreak build)

Commit 122394f1476b1c925a281b15399119500c8231c1 ("Function for reading
the Aarch64 SVE vector length") has added macros to manipulate SVE
vector sizes based on Linux kernel sources, but did not guard them
with #ifndef's, which breaks the build when the system headers already
have these macros:

    CXX    aarch64-linux-nat.o
  In file included from ../../gdb/aarch64-tdep.h:25,
                   from ../../gdb/aarch64-linux-nat.c:30:
  ../../gdb/arch/aarch64.h:79: error: "sve_vq_from_vl" redefined [-Werror]
   #define sve_vq_from_vl(vl) ((vl) / 0x10)

  In file included from /usr/include/bits/sigcontext.h:30,
                   from /usr/include/signal.h:291,
                   from build-gnulib/import/signal.h:52,
                   from ../../gdb/linux-nat.h:23,
                   from ../../gdb/aarch64-linux-nat.c:26:
  /usr/include/asm/sigcontext.h:154: note: this is the location of the previous definition
   #define sve_vq_from_vl(vl) ((vl) / SVE_VQ_BYTES)

  In file included from ../../gdb/aarch64-tdep.h:25,
                   from ../../gdb/aarch64-linux-nat.c:30:
  ../../gdb/arch/aarch64.h:80: error: "sve_vl_from_vq" redefined [-Werror]
   #define sve_vl_from_vq(vq) ((vq) * 0x10)

  In file included from /usr/include/bits/sigcontext.h:30,
                   from /usr/include/signal.h:291,
                   from build-gnulib/import/signal.h:52,
                   from ../../gdb/linux-nat.h:23,
                   from ../../gdb/aarch64-linux-nat.c:26:
  /usr/include/asm/sigcontext.h:155: note: this is the location of the previous definition
   #define sve_vl_from_vq(vq) ((vq) * SVE_VQ_BYTES)

In order to fix this breakage, this commit guards the declaration of
the macros using #ifndef's.

gdb/ChangeLog:
2018-06-06  Sergio Durigan Junior  <sergiodj@redhat.com>

	* arch/aarch64.h (sve_vg_from_vl): Guard with #ifndef.
	(sve_vl_from_vg): Likewise.
	(sve_vq_from_vl): Likewise.
	(sve_vl_from_vq): Likewise.
	(sve_vq_from_vg): Likewise.
	(sve_vg_from_vq): Likewise.

diff --git a/gdb/arch/aarch64.h b/gdb/arch/aarch64.h
index 9040d8d4c868cb77fec5176ada1e4d6586795b29..e344a367707be48f47f162a1433083c05bf49ae6 100644 (file)
--- a/gdb/arch/aarch64.h
+++ b/gdb/arch/aarch64.h
@@ -76,8 +76,12 @@ enum aarch64_regnum
 
 #define sve_vg_from_vl(vl)     ((vl) / 8)
 #define sve_vl_from_vg(vg)     ((vg) * 8)
+#ifndef sve_vq_from_vl
 #define sve_vq_from_vl(vl)     ((vl) / 0x10)
+#endif
+#ifndef sve_vl_from_vq
 #define sve_vl_from_vq(vq)     ((vq) * 0x10)
+#endif
 #define sve_vq_from_vg(vg)     (sve_vq_from_vl (sve_vl_from_vg (vg)))
 #define sve_vg_from_vq(vq)     (sve_vg_from_vl (sve_vl_from_vq (vq)))