From: Richard Henderson <richard.henderson@linaro.org>
To: libc-alpha@sourceware.org
Cc: carlos@redhat.com, fweimer@redhat.com
Subject: [RESEND PATCH] Makeconfig: Set pie-ccflag to -fPIE by default
Date: Thu, 25 Aug 2022 14:01:03 -0700 [thread overview]
Message-ID: <20220825210103.2259134-1-richard.henderson@linaro.org> (raw)
[ I never saw this arrive in the list archives.
Trying again with my linaro address subscribed. ]
We should default to the larger code model, in order to support
larger applications built with -static -pie. This should be
consistent with pic-ccflag, which defaults to -fPIC.
Remove the now redundant override from sysdeps/sparc/Makefile.
Note that -fno-pie and -fno-PIE have the same effect.
---
In the case of AArch64, the code changes are small but significant:
0000000000000000 <__libc_init_first>:
0: a9bd7bfd stp x29, x30, [sp, #-48]!
- 4: 90000003 adrp x3, 0 <_GLOBAL_OFFSET_TABLE_>
- 4: R_AARCH64_ADR_PREL_PG_HI21 _GLOBAL_OFFSET_TABLE_
+ 4: 90000003 adrp x3, 0 <__environ>
+ 4: R_AARCH64_ADR_GOT_PAGE __environ
8: 90000004 adrp x4, 0 <__libc_init_first>
8: R_AARCH64_ADR_PREL_PG_HI21 .bss
c: 910003fd mov x29, sp
10: f9400063 ldr x3, [x3]
- 10: R_AARCH64_LD64_GOTPAGE_LO15 __environ
+ 10: R_AARCH64_LD64_GOT_LO12_NC __environ
In the small model, we are constrained to 15 bits of GOT, with a
single shared base, _GLOBAL_OFFSET_TABLE_. In the large model,
each symbol has a page + offset pair. For small functions like
this, where there are no other variable references to share the
common GOT pointer, there is no actual code change.
r~
---
Makeconfig | 2 +-
sysdeps/sparc/Makefile | 3 ---
2 files changed, 1 insertion(+), 4 deletions(-)
diff --git a/Makeconfig b/Makeconfig
index e78cf220af..f8164a0025 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -1052,7 +1052,7 @@ pic-ccflag = -fPIC
PIC-ccflag = -fPIC
endif
# This can be changed by a sysdep makefile
-pie-ccflag = -fpie
+pie-ccflag = -fPIE
no-pie-ccflag = -fno-pie
# This one should always stay like this unless there is a very good reason.
PIE-ccflag = -fPIE
diff --git a/sysdeps/sparc/Makefile b/sysdeps/sparc/Makefile
index 12c2c1b085..26b4a84606 100644
--- a/sysdeps/sparc/Makefile
+++ b/sysdeps/sparc/Makefile
@@ -1,9 +1,6 @@
# The Sparc `long double' is a distinct type we support.
long-double-fcts = yes
-pie-ccflag = -fPIE
-no-pie-ccflag = -fno-PIE
-
ifeq ($(subdir),gmon)
sysdep_routines += sparc-mcount
endif
--
2.34.1
next reply other threads:[~2022-08-25 21:01 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-25 21:01 Richard Henderson [this message]
2022-08-26 12:32 ` Adhemerval Zanella Netto
2022-08-26 17:29 ` Richard Henderson
2022-08-26 18:39 Wilco Dijkstra
2022-08-26 19:02 ` H.J. Lu
2022-08-26 19:45 ` Richard Henderson
2022-08-26 20:11 ` H.J. Lu
2022-08-29 11:49 ` Wilco Dijkstra
2022-08-29 13:10 ` Florian Weimer
2022-08-29 15:27 ` Wilco Dijkstra
2022-08-29 15:27 ` Wilco Dijkstra
2022-08-29 19:43 ` H.J. Lu
2022-08-29 19:57 ` Fangrui Song
2022-09-05 8:58 ` Wilco Dijkstra
2022-09-15 21:45 ` Fangrui Song
2022-09-20 13:59 ` Wilco Dijkstra
2022-09-20 14:12 ` Florian Weimer
2022-09-20 16:00 ` Wilco Dijkstra
2022-09-20 22:02 ` Fangrui Song
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