[Buildroot] [PATCH v3] toolchain-external: Fix EABIhf check

* [Buildroot] [PATCH v3] toolchain-external: Fix EABIhf check
@ 2014-05-06 11:25 Thomas De Schampheleire
  2014-05-08 22:35 ` Arnout Vandecappelle
  0 siblings, 1 reply; 4+ messages in thread
From: Thomas De Schampheleire @ 2014-05-06 11:25 UTC (permalink / raw)
  To: buildroot

From: Stefan S?rensen <stefan.sorensen@spectralink.com>

Currently the check for EABI/EABIhf toolchains looks for the
Tag_ABI_VFP_args attribute in the crt1.o file which gcc adds in an
EABIhf toolchain.
In uClibc, however, crt1.o is not compiled from c but assembly, so the
Tag_ABI_VFP_args attribute is not added in the object file. This causes
the EABIhf check in the external toolchain logic to fail for
uClibc-based toolchains.

Fix by compiling a dummy .c file and trying to link the object against the
C library. Since it is impossible to mix EABI and EABIhf code, a mismatch
between the buildroot and toolchain ABI settings will be detected during
this link step.

Fixes bug #6842: https://bugs.busybox.net/show_bug.cgi?id=6842

Signed-off-by: Stefan S?rensen <stefan.sorensen@spectralink.com>
[ThomasDS: do full link iso readelf test, update commit message]
Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>

---
v3: (ThomasDS)
  - v2 properly recognized a uClibc EABIhf toolchain, but failed to detect a
    mismatch with buildroot settings (detected by ThomasP). Fix by
    performing an actual link step to detect any incompatibility.
v2: (ThomasDS)
  - avoid creating a temporary source file
  - update commit message

 toolchain/helpers.mk |  18 ++++++------------
 1 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/toolchain/helpers.mk b/toolchain/helpers.mk
--- a/toolchain/helpers.mk
+++ b/toolchain/helpers.mk
@@ -297,20 +297,14 @@ check_arm_abi = \
 		echo "External toolchain uses the unsuported OABI" ; \
 		exit 1 ; \
 	fi ; \
-	EXT_TOOLCHAIN_CRT1=`LANG=C $${__CROSS_CC} -print-file-name=crt1.o` ; \
-	if $${__CROSS_READELF} -A $${EXT_TOOLCHAIN_CRT1} | grep -q "Tag_ABI_VFP_args:" ; then \
-		EXT_TOOLCHAIN_ABI="eabihf" ; \
-	else \
-		EXT_TOOLCHAIN_ABI="eabi" ; \
-	fi ; \
-	if [ "$(BR2_ARM_EABI)" = "y" -a "$${EXT_TOOLCHAIN_ABI}" = "eabihf" ] ; then \
-		echo "Incorrect ABI setting: EABI selected, but toolchain uses EABIhf" ; \
+	TEMP_OBJ_FILE=`mktemp --tmpdir --suffix=.o`; \
+	if ! echo 'int main(void) {}' | $${__CROSS_CC} -x c -o $${TEMP_OBJ_FILE} /dev/null - 2>/dev/null; then \
+		abistr_$(BR2_ARM_EABI)='EABI'; \
+		abistr_$(BR2_ARM_EABIHF)='EABIhf'; \
+		echo "Incorrect ABI setting: $${abistr_y} selected, but toolchain is incompatible"; \
 		exit 1 ; \
 	fi ; \
-	if [ "$(BR2_ARM_EABIHF)" = "y" -a "$${EXT_TOOLCHAIN_ABI}" = "eabi" ] ; then \
-		echo "Incorrect ABI setting: EABIhf selected, but toolchain uses EABI" ; \
-		exit 1 ; \
-	fi
+	rm -f $${TEMP_OBJ_FILE}
 
 #
 # Check that the external toolchain supports C++

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