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[PATCH 4/6] conf/i386-cygwin-img-ld: Do not discard .data and .edata sec
From: |
Daniel Kiper |
Subject: |
[PATCH 4/6] conf/i386-cygwin-img-ld: Do not discard .data and .edata sections |
Date: |
Fri, 11 Mar 2022 00:35:58 +0100 |
$ ./configure --target=i686-w64-mingw32 --with-platform=efi
--host=i686-w64-mingw32
[...]
checking if __bss_start is defined by the compiler... no
checking if edata is defined by the compiler... no
checking if _edata is defined by the compiler... no
configure: error: none of __bss_start, edata or _edata is defined
This happens on machines with quite recent ld due to an error:
`edata' referenced in section `.text' of /tmp/cc72w9E4.o: defined in
discarded section `.data' of conftest.exe
collect2: error: ld returned 1 exit status
So, we have to tell linker to not discard .data and .edata sections.
The trick comes from ld documentation:
3.6.7 Output Section Discarding
The linker will not normally create output sections with no contents.
This is for convenience when referring to input sections that may or may
not be present in any of the input files. For example:
.foo : { *(.foo) }
will only create a ‘.foo’ section in the output file if there is a
‘.foo’ section in at least one input file, and if the input sections are
not all empty. Other link script directives that allocate space in an
output section will also create the output section. So too will
assignments to dot even if the assignment does not create space, except
for ‘. = 0’, ‘. = . + 0’, ‘. = sym’, ‘. = . + sym’ and ‘. = ALIGN (. !=
0, expr, 1)’ when ‘sym’ is an absolute symbol of value 0 defined in the
script. This allows you to force output of an empty section with ‘. = .’.
This change does not impact generated binaries because the
conf/i386-cygwin-img-ld.sc linker script is used only when
you run configure.
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
---
conf/i386-cygwin-img-ld.sc | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/conf/i386-cygwin-img-ld.sc b/conf/i386-cygwin-img-ld.sc
index 3ac26fcce..578da91b0 100644
--- a/conf/i386-cygwin-img-ld.sc
+++ b/conf/i386-cygwin-img-ld.sc
@@ -14,6 +14,8 @@ SECTIONS
{
__data_start__ = . ;
*(.data)
+ /* Do not discard this section. */
+ . = . ;
__data_end__ = . ;
__rdata_start__ = . ;
*(.rdata)
@@ -34,6 +36,8 @@ SECTIONS
.edata :
{
*(.edata)
+ /* Do not discard this section. */
+ . = . ;
end = . ;
_end = . ;
__end = . ;
--
2.11.0