73 lines
2.9 KiB
Diff
73 lines
2.9 KiB
Diff
From thiago.bauermann@linaro.org Fri Dec 27 21:47:56 2024
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From: thiago.bauermann@linaro.org (Thiago Jung Bauermann)
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Date: Fri, 27 Dec 2024 18:47:56 -0300
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Subject: [PATCH] gcc/configure: Fix check for assembler section merging
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support on Arm
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Message-ID: <20241227214756.1059146-1-thiago.bauermann@linaro.org>
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In 32-bit Arm assembly, the @ character is the start of a comment so
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the section type needs to use the % character instead.
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configure.ac attempts to account for this difference by doing a second
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try when checking the assembler for section merging support.
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Unfortunately there is a bug: because the gcc_GAS_CHECK_FEATURE macro
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has a call to AC_CACHE_CHECK, it will actually skip the second try
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because the gcc_cv_as_shf_merge variable has already been set:
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checking assembler for section merging support... no
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checking assembler for section merging support... (cached) no
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Fix by using a separate variable for the second try, as is done in the
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check for COMDAT group support.
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This problem was noticed because the recent binutils commit
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d5cbf916be4a ("gas/ELF: also reject merge entity size being zero") caused
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gas to be stricter about mergeable sections without an entity size:
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configure:27013: checking assembler for section merging support
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configure:27022: /path/to/as --fatal-warnings -o conftest.o conftest.s >&5
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conftest.s: Assembler messages:
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conftest.s:1: Warning: invalid merge / string entity size
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conftest.s: Error: 1 warning, treating warnings as errors
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configure:27025: $? = 1
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configure: failed program was
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.section .rodata.str, "aMS", @progbits, 1
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configure:27036: result: no
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In previous versions of gas the conftest.s program above was accepted
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and configure detected support for section merging.
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See also:
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https://linaro.atlassian.net/browse/GNU-1427
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https://sourceware.org/bugzilla/show_bug.cgi?id=32491
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Tested on armv8l-linux-gnueabihf.
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gcc/ChangeLog:
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* configure.ac: Fix check for HAVE_GAS_SHF_MERGE on Arm targets.
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* configure: Regenerate.
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---
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gcc/configure | 17 +++++++++--------
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gcc/configure.ac | 6 ++++--
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2 files changed, 13 insertions(+), 10 deletions(-)
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--- a/src/gcc/configure.ac
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+++ b/src/gcc/configure.ac
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@@ -3606,12 +3606,14 @@ gcc_GAS_CHECK_FEATURE(section merging su
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[--fatal-warnings],
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[.section .rodata.str, "aMS", @progbits, 1])
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if test $gcc_cv_as_shf_merge = no; then
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- gcc_GAS_CHECK_FEATURE(section merging support, gcc_cv_as_shf_merge,
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+ gcc_GAS_CHECK_FEATURE(section merging support (%progbits),
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+ gcc_cv_as_shf_merge_percent,
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[--fatal-warnings],
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[.section .rodata.str, "aMS", %progbits, 1])
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fi
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AC_DEFINE_UNQUOTED(HAVE_GAS_SHF_MERGE,
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- [`if test $gcc_cv_as_shf_merge = yes; then echo 1; else echo 0; fi`],
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+ [`if test $gcc_cv_as_shf_merge = yes \
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+ || test $gcc_cv_as_shf_merge_percent = yes; then echo 1; else echo 0; fi`],
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[Define 0/1 if your assembler supports marking sections with SHF_MERGE flag.])
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gcc_cv_ld_aligned_shf_merge=yes
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