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Prevent silly text-segment alignment on all platforms 

We set 'ld -z max-page-size' to 4KiB to prevent the linker from aligning
the text segment to any built-in default (e.g., 4MiB on x86_64 or 64KiB
on ARM). Otherwise, the padding bytes are wasted at the beginning of the
final binary.
This commit is contained in:
Christian Helmuth 2015-06-25 17:52:25 +02:00
parent 463c9bec17
commit 11c31c4432
2 changed files with 7 additions and 3 deletions
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8
repos/base/mk/global.mk
View File

@ -129,11 +129,15 @@ CC_CXX_OPT += $(CC_CXX_OPT_STD)
# Use '-gc-sections' by default but allow a platform to disable this feature by
# defining 'LD_GC_SECTIONS' empty. This is needed for older tool chains (gcc
# version 4.11 and binutils version 2.16), which happen to produce broken
# code when '-gc-sections' is enabled.
# code when '-gc-sections' is enabled. Also, set max-page-size to 4KiB to
# prevent the linker from aligning the text segment to any built-in default
# (e.g., 4MiB on x86_64 or 64KiB on ARM). Otherwise, the padding bytes are
# wasted at the beginning of the final binary.
#
LD_OPT_GC_SECTIONS ?= -gc-sections
LD_OPT_ALIGN_SANE = -z max-page-size=0x1000
LD_OPT_PREFIX := -Wl,
LD_OPT += $(LD_MARCH) $(LD_OPT_GC_SECTIONS)
LD_OPT += $(LD_MARCH) $(LD_OPT_GC_SECTIONS) $(LD_OPT_ALIGN_SANE)
CXX_LINK_OPT += $(addprefix $(LD_OPT_PREFIX),$(LD_OPT))
CXX_LINK_OPT += $(LD_OPT_NOSTDLIB)

2
repos/base/mk/spec-x86_64.mk
View File

@ -19,7 +19,7 @@ CC_MARCH ?= -m64
#
# See http://sourceware.org/ml/binutils/2009-04/msg00099.html
#
LD_MARCH ?= -melf_x86_64 -z max-page-size=0x1000
LD_MARCH ?= -melf_x86_64
include $(call select_from_repositories,mk/spec-64bit.mk)