[google/gcc-4_6] Backport arm hardfp patch from trunk

Hi Rong and Carrot, could you take a look at this patch, thanks! 

The modification is in upstream (with a minor modification).
Trunk patch revision - 186859.

Background - 

There is the need to agree on the runtime linker path for the various ARM hard-float ports that distros are working on right now. Without doing this, we'll break binary compatibility between the distros.

The conclusion was made. And here is the detailed information - https://wiki.linaro.org/OfficeofCTO/HardFloat/LinkerPathCallApr2012

===== Patch starts
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index 3a32188..58d06c2 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -32,7 +32,8 @@
   while (false)
 
 /* We default to a soft-float ABI so that binaries can run on all
-   target hardware.  */
+   target hardware.  If you override this to use the hard-float ABI then
+   change the setting of GLIBC_DYNAMIC_LINKER_DEFAULT as well.  */
 #undef  TARGET_DEFAULT_FLOAT_ABI
 #define TARGET_DEFAULT_FLOAT_ABI ARM_FLOAT_ABI_SOFT
 
@@ -59,10 +60,26 @@
 #undef  SUBTARGET_EXTRA_LINK_SPEC
 #define SUBTARGET_EXTRA_LINK_SPEC " -m " TARGET_LINKER_EMULATION
 
-/* Use ld-linux.so.3 so that it will be possible to run "classic"
-   GNU/Linux binaries on an EABI system.  */
+/* GNU/Linux on ARM currently supports three dynamic linkers:
+   - ld-linux.so.2 - for the legacy ABI
+   - ld-linux.so.3 - for the EABI-derived soft-float ABI
+   - ld-linux-armhf.so.3 - for the EABI-derived hard-float ABI.
+   All the dynamic linkers live in /lib.
+   We default to soft-float, but this can be overridden by changing both
+   GLIBC_DYNAMIC_LINKER_DEFAULT and TARGET_DEFAULT_FLOAT_ABI.  */
+
 #undef  GLIBC_DYNAMIC_LINKER
-#define GLIBC_DYNAMIC_LINKER RUNTIME_ROOT_PREFIX "/lib/ld-linux.so.3"
+#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT \
+  RUNTIME_ROOT_PREFIX "/lib/ld-linux.so.3"
+#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT \
+  RUNTIME_ROOT_PREFIX "/lib/ld-linux-armhf.so.3"
+#define GLIBC_DYNAMIC_LINKER_DEFAULT \
+  RUNTIME_ROOT_PREFIX GLIBC_DYNAMIC_LINKER_SOFT_FLOAT
+
+#define GLIBC_DYNAMIC_LINKER \
+   "%{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \
+    %{mfloat-abi=soft*:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "} \
+    %{!mfloat-abi=*:" GLIBC_DYNAMIC_LINKER_DEFAULT "}"
 
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */

[shenhan, 2012-05-11 18:26:40]

Hi Rong and Carrot, could you take a look at this patch, thanks! 

The modification is in upstream (with a minor modification).

Background - 

There is the need to agree on the runtime linker path for the various ARM
hard-float ports that distros are working on right now. Without doing this,
we'll break binary compatibility between the distros.

The conclusion was made. And here is the detailed information -
https://wiki.linaro.org/OfficeofCTO/HardFloat/LinkerPathCallApr2012

===== Patch starts
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index 3a32188..58d06c2 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -32,7 +32,8 @@
   while (false)
 
 /* We default to a soft-float ABI so that binaries can run on all
-   target hardware.  */
+   target hardware.  If you override this to use the hard-float ABI then
+   change the setting of GLIBC_DYNAMIC_LINKER_DEFAULT as well.  */
 #undef  TARGET_DEFAULT_FLOAT_ABI
 #define TARGET_DEFAULT_FLOAT_ABI ARM_FLOAT_ABI_SOFT
 
@@ -59,10 +60,26 @@
 #undef  SUBTARGET_EXTRA_LINK_SPEC
 #define SUBTARGET_EXTRA_LINK_SPEC " -m " TARGET_LINKER_EMULATION
 
-/* Use ld-linux.so.3 so that it will be possible to run "classic"
-   GNU/Linux binaries on an EABI system.  */
+/* GNU/Linux on ARM currently supports three dynamic linkers:
+   - ld-linux.so.2 - for the legacy ABI
+   - ld-linux.so.3 - for the EABI-derived soft-float ABI
+   - ld-linux-armhf.so.3 - for the EABI-derived hard-float ABI.
+   All the dynamic linkers live in /lib.
+   We default to soft-float, but this can be overridden by changing both
+   GLIBC_DYNAMIC_LINKER_DEFAULT and TARGET_DEFAULT_FLOAT_ABI.  */
+
 #undef  GLIBC_DYNAMIC_LINKER
-#define GLIBC_DYNAMIC_LINKER RUNTIME_ROOT_PREFIX "/lib/ld-linux.so.3"
+#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT \
+  RUNTIME_ROOT_PREFIX "/lib/ld-linux.so.3"
+#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT \
+  RUNTIME_ROOT_PREFIX "/lib/ld-linux-armhf.so.3"
+#define GLIBC_DYNAMIC_LINKER_DEFAULT \
+  RUNTIME_ROOT_PREFIX GLIBC_DYNAMIC_LINKER_SOFT_FLOAT
+
+#define GLIBC_DYNAMIC_LINKER \
+   "%{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \
+    %{mfloat-abi=soft*:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "} \
+    %{!mfloat-abi=*:" GLIBC_DYNAMIC_LINKER_DEFAULT "}"
 
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */

[carrot, 2012-05-11 18:48:40]

Please add ChangeLog and the trunk patch revision.

[shenhan, 2012-05-11 21:46:22]

On 2012/05/11 18:48:40, carrot wrote:
> Please add ChangeLog and the trunk patch revision.

Thanks.

Trunk patch revision is 186859.

ChangeLog entry added.

==== Patch started.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2f85855..588fa04 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2012-05-11  Han Shen  <shenhan@google.com>
+
+	Backport from mainline.
+	2012-04-26  Michael Hope  <michael.hope@linaro.org>
+		    Richard Earnshaw  <rearnsha@arm.com>
+
+	* config/arm/linux-eabi.h (GLIBC_DYNAMIC_LINKER_SOFT_FLOAT): Define.
+	(GLIBC_DYNAMIC_LINKER_HARD_FLOAT): Define.
+	(GLIBC_DYNAMIC_LINKER_DEFAULT): Define.
+	(GLIBC_DYNAMIC_LINKER):	Redefine to use the hard float path.
+
 2012-04-30  Uros Bizjak  <ubizjak@gmail.com>
 
 	Backport from mainline
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index 3a32188..58d06c2 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -32,7 +32,8 @@
   while (false)
 
 /* We default to a soft-float ABI so that binaries can run on all
-   target hardware.  */
+   target hardware.  If you override this to use the hard-float ABI then
+   change the setting of GLIBC_DYNAMIC_LINKER_DEFAULT as well.  */
 #undef  TARGET_DEFAULT_FLOAT_ABI
 #define TARGET_DEFAULT_FLOAT_ABI ARM_FLOAT_ABI_SOFT
 
@@ -59,10 +60,26 @@
 #undef  SUBTARGET_EXTRA_LINK_SPEC
 #define SUBTARGET_EXTRA_LINK_SPEC " -m " TARGET_LINKER_EMULATION
 
-/* Use ld-linux.so.3 so that it will be possible to run "classic"
-   GNU/Linux binaries on an EABI system.  */
+/* GNU/Linux on ARM currently supports three dynamic linkers:
+   - ld-linux.so.2 - for the legacy ABI
+   - ld-linux.so.3 - for the EABI-derived soft-float ABI
+   - ld-linux-armhf.so.3 - for the EABI-derived hard-float ABI.
+   All the dynamic linkers live in /lib.
+   We default to soft-float, but this can be overridden by changing both
+   GLIBC_DYNAMIC_LINKER_DEFAULT and TARGET_DEFAULT_FLOAT_ABI.  */
+
 #undef  GLIBC_DYNAMIC_LINKER
-#define GLIBC_DYNAMIC_LINKER RUNTIME_ROOT_PREFIX "/lib/ld-linux.so.3"
+#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT \
+  RUNTIME_ROOT_PREFIX "/lib/ld-linux.so.3"
+#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT \
+  RUNTIME_ROOT_PREFIX "/lib/ld-linux-armhf.so.3"
+#define GLIBC_DYNAMIC_LINKER_DEFAULT \
+  RUNTIME_ROOT_PREFIX GLIBC_DYNAMIC_LINKER_SOFT_FLOAT
+
+#define GLIBC_DYNAMIC_LINKER \
+   "%{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \
+    %{mfloat-abi=soft*:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "} \
+    %{!mfloat-abi=*:" GLIBC_DYNAMIC_LINKER_DEFAULT "}"
 
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */

[carrot, 2012-05-11 22:15:37]

http://codereview.appspot.com/6206055/diff/4001/gcc/ChangeLog
File gcc/ChangeLog (right):

http://codereview.appspot.com/6206055/diff/4001/gcc/ChangeLog#newcode11
gcc/ChangeLog:11: 
It seems you also merged in another patch r187012, please mention it.

http://codereview.appspot.com/6206055/diff/4001/gcc/config/arm/linux-eabi.h
File gcc/config/arm/linux-eabi.h (right):

http://codereview.appspot.com/6206055/diff/4001/gcc/config/arm/linux-eabi.h#n...
gcc/config/arm/linux-eabi.h:77: RUNTIME_ROOT_PREFIX
GLIBC_DYNAMIC_LINKER_SOFT_FLOAT

Here the RUNTIME_ROOT_PREFIX may be redundant.

[shenhan, 2012-05-14 17:16:52]

On 2012/05/11 22:15:37, carrot wrote:
> http://codereview.appspot.com/6206055/diff/4001/gcc/ChangeLog
> File gcc/ChangeLog (right):
> 
> http://codereview.appspot.com/6206055/diff/4001/gcc/ChangeLog#newcode11
> gcc/ChangeLog:11: 
> It seems you also merged in another patch r187012, please mention it.
> 
> http://codereview.appspot.com/6206055/diff/4001/gcc/config/arm/linux-eabi.h
> File gcc/config/arm/linux-eabi.h (right):
> 
>
http://codereview.appspot.com/6206055/diff/4001/gcc/config/arm/linux-eabi.h#n...
> gcc/config/arm/linux-eabi.h:77: RUNTIME_ROOT_PREFIX
> GLIBC_DYNAMIC_LINKER_SOFT_FLOAT
> 
> Here the RUNTIME_ROOT_PREFIX may be redundant.

Hi Carrot, thanks!

Modified per your comments.

========= Patch start

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2f85855..afe7769 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,19 @@
+2012-05-11  Han Shen  <shenhan@google.com>
+
+	Backport from mainline.
+	2012-05-01  Richard Earnshaw  <rearnsha@arm.com>
+
+	* arm/linux-eabi.h (GLIBC_DYNAMIC_LINKER_DEFAULT): Avoid ifdef
+	comparing enumeration values.  Update comments.
+
+	2012-04-26  Michael Hope  <michael.hope@linaro.org>
+		    Richard Earnshaw  <rearnsha@arm.com>
+
+	* config/arm/linux-eabi.h (GLIBC_DYNAMIC_LINKER_SOFT_FLOAT): Define.
+	(GLIBC_DYNAMIC_LINKER_HARD_FLOAT): Define.
+	(GLIBC_DYNAMIC_LINKER_DEFAULT): Define.
+	(GLIBC_DYNAMIC_LINKER):	Redefine to use the hard float path.
+
 2012-04-30  Uros Bizjak  <ubizjak@gmail.com>
 
 	Backport from mainline
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index 3a32188..e1d3415 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -32,7 +32,8 @@
   while (false)
 
 /* We default to a soft-float ABI so that binaries can run on all
-   target hardware.  */
+   target hardware.  If you override this to use the hard-float ABI then
+   change the setting of GLIBC_DYNAMIC_LINKER_DEFAULT as well.  */
 #undef  TARGET_DEFAULT_FLOAT_ABI
 #define TARGET_DEFAULT_FLOAT_ABI ARM_FLOAT_ABI_SOFT
 
@@ -59,10 +60,25 @@
 #undef  SUBTARGET_EXTRA_LINK_SPEC
 #define SUBTARGET_EXTRA_LINK_SPEC " -m " TARGET_LINKER_EMULATION
 
-/* Use ld-linux.so.3 so that it will be possible to run "classic"
-   GNU/Linux binaries on an EABI system.  */
+/* GNU/Linux on ARM currently supports three dynamic linkers:
+   - ld-linux.so.2 - for the legacy ABI
+   - ld-linux.so.3 - for the EABI-derived soft-float ABI
+   - ld-linux-armhf.so.3 - for the EABI-derived hard-float ABI.
+   All the dynamic linkers live in /lib.
+   We default to soft-float, but this can be overridden by changing both
+   GLIBC_DYNAMIC_LINKER_DEFAULT and TARGET_DEFAULT_FLOAT_ABI.  */
+
 #undef  GLIBC_DYNAMIC_LINKER
-#define GLIBC_DYNAMIC_LINKER RUNTIME_ROOT_PREFIX "/lib/ld-linux.so.3"
+#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT \
+  RUNTIME_ROOT_PREFIX "/lib/ld-linux.so.3"
+#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT \
+  RUNTIME_ROOT_PREFIX "/lib/ld-linux-armhf.so.3"
+#define GLIBC_DYNAMIC_LINKER_DEFAULT GLIBC_DYNAMIC_LINKER_SOFT_FLOAT
+
+#define GLIBC_DYNAMIC_LINKER \
+   "%{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \
+    %{mfloat-abi=soft*:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "} \
+    %{!mfloat-abi=*:" GLIBC_DYNAMIC_LINKER_DEFAULT "}"
 
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */
=============

[carrot, 2012-05-14 23:49:09]

OK for google branch.

google/gcc-4_7 may also need this patch.