[PATCH] Makeconfig: Set pie-ccflag to -fPIE by default [BZ# 29514]

[Richard Henderson]

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.

---

For 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.

For s390x, I would expect changes similar to c64a10e54441, and
an eventual similar bug report if this were left unchanged.

For x86, ppc64 and riscv64, -fpie & -fPIE are identical.

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