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gcc: explicitly use C{XX}FLAGS_FOR_TARGET instead of --enable-target-optspace

PATCH Superseded Alexey Brodkin 2 participants 3 messages Mar 24, 2015 – Jul 22, 2015

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Alexey Brodkin

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#0 lore raw

PATCH v5 1/1 gcc: explicitly use C{XX}FLAGS_FOR_TARGET instead of --enable-target-optspace

The gcc.mk file is passing --enable-target-optspace to gcc configure script, to ask for space-optimized (-Os) target libraries. However, passing this option has the effect of overriding any custom CFLAGS_FOR_TARGET or CXXFLAGS_FOR_TARGET values that may be passed.

These are some situations when it is required to pass custom flags on buildong
of libgcc:
* Default flags "-g -Os" lead to build isses as with PowerPC on gcc 4.5
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43810)
* Particular CPU requires specific instructions for HW support
* Deep optimizations

Signed-off-by Alexey Brodkin <[email protected]>
Cc Anton Kolesov <[email protected]>
Cc Thomas Petazzoni <[email protected]>
Cc Peter Korsgaard <[email protected]>
Cc Gustavo Zacarias <[email protected]>

---
Compared to v3 use "=" instead of ":=" which is not actually required here. Compared to v4 simply rebased on top of today's master

---
 package/gcc/gcc.mk | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
package/gcc/gcc.mk +9 -3
index b5d2ddb..7086969 100644
@@ -100,16 +100,22 @@ HOST_GCC_COMMON_CONF_OPTS = \
 HOST_GCC_COMMON_CONF_ENV = \
 	MAKEINFO=missing
 
+GCC_COMMON_TARGET_CFLAGS = $(TARGET_CFLAGS)
+GCC_COMMON_TARGET_CXXFLAGS = $(TARGET_CXXFLAGS)
+
 # http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43810
 # Workaround until it's fixed in 4.5.4 or later
 ifeq ($(ARCH),powerpc)
 ifeq ($(findstring x4.5.,x$(GCC_VERSION)),x4.5.)
-HOST_GCC_COMMON_CONF_OPTS += --disable-target-optspace
+GCC_COMMON_TARGET_CFLAGS = $(filter-out -Os,$(GCC_COMMON_TARGET_CFLAGS))
+GCC_COMMON_TARGET_CXXFLAGS = $(filter-out -Os,$(GCC_COMMON_TARGET_CXXFLAGS))
 endif
-else
-HOST_GCC_COMMON_CONF_OPTS += --enable-target-optspace
 endif
 
+# Propagate options used for target software building to GCC target libs
+HOST_GCC_COMMON_CONF_ENV += CFLAGS_FOR_TARGET="$(GCC_COMMON_TARGET_CXXFLAGS)"
+HOST_GCC_COMMON_CONF_ENV += CXXFLAGS_FOR_TARGET="$(GCC_COMMON_TARGET_CXXFLAGS)"
+
 # libitm needs sparc V9+
 ifeq ($(BR2_sparc_v8)$(BR2_sparc_leon3),y)
 HOST_GCC_COMMON_CONF_OPTS += --disable-libitm
Signature · 1 line
2.1.0
author
#1 lore raw

PATCH v5 1/1 gcc: explicitly use C{XX}FLAGS_FOR_TARGET instead of --enable-target-optspace

Hi Thomas,

Quoted 18 lines · Alexey Brodkin

The gcc.mk file is passing --enable-target-optspace to gcc configure script, to ask for space-optimized (-Os) target libraries. However, passing this option has the effect of overriding any custom CFLAGS_FOR_TARGET or CXXFLAGS_FOR_TARGET values that may be passed.

These are some situations when it is required to pass custom flags on buildong
of libgcc:
* Default flags "-g -Os" lead to build isses as with PowerPC on gcc 4.5
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43810)
* Particular CPU requires specific instructions for HW support
* Deep optimizations

Signed-off-by Alexey Brodkin <[email protected]>
Cc Anton Kolesov <[email protected]>
Cc Thomas Petazzoni <[email protected]>
Cc Peter Korsgaard <[email protected]>
Cc Gustavo Zacarias <[email protected]>
Quoted 4 lines

---
Compared to v3 use "=" instead of ":=" which is not actually required here. Compared to v4 simply rebased on top of today's master
---

I just got a reminder about my pending Buildroot patches.

I'm still interested in that patch. We had a long discussion of that change in the past and keeping in mind importance of the item (libgcc) it indeed requires careful testing etc.

But maybe if we're OK with the change patch introduces we may try to apply it and see how many problems autobuilder will produce with it.

-Alexey

Applied
#2 lore raw

PATCH v5 1/1 gcc: explicitly use C{XX}FLAGS_FOR_TARGET instead of --enable-target-optspace

In reply to Alexey Brodkin

Dear Alexey Brodkin,

Quoted 18 lines · Alexey Brodkin

The gcc.mk file is passing --enable-target-optspace to gcc configure script, to ask for space-optimized (-Os) target libraries. However, passing this option has the effect of overriding any custom CFLAGS_FOR_TARGET or CXXFLAGS_FOR_TARGET values that may be passed.

These are some situations when it is required to pass custom flags on buildong
of libgcc:
* Default flags "-g -Os" lead to build isses as with PowerPC on gcc 4.5
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43810)
* Particular CPU requires specific instructions for HW support
* Deep optimizations

Signed-off-by Alexey Brodkin <[email protected]>
Cc Anton Kolesov <[email protected]>
Cc Thomas Petazzoni <[email protected]>
Cc Peter Korsgaard <[email protected]>
Cc Gustavo Zacarias <[email protected]>
Quoted 6 lines

---
Compared to v3 use "=" instead of ":=" which is not actually required here. Compared to v4 simply rebased on top of today's master

---
 package/gcc/gcc.mk | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Applied, thanks.

Thomas

Signature · 3 lines
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com