libffi: add patch to revert clang VFP workaround

Patch is added to address an issue preventing libffi
from compiling under clang.

Change-Id: I55e36d252ec8e84de9b35fea18044c2c0e8c5aab
(From OE-Core rev: a4944e9b553ddf55da9d9a1243fadc93a620b003)

Signed-off-by: Brett Warren <brett.warren@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 01e8c53488dd5ebb206bef2415549e8ac1ac7601)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 105 insertions, 0 deletions

diff --git a/meta/recipes-support/libffi/libffi/0001-arm-sysv-reverted-clang-VFP-mitigation.patch b/meta/recipes-support/libffi/libffi/0001-arm-sysv-reverted-clang-VFP-mitigation.patch
new file mode 100644
index 0000000000..782dce70d8
--- /dev/null
+++ b/meta/recipes-support/libffi/libffi/0001-arm-sysv-reverted-clang-VFP-mitigation.patch
@@ -0,0 +1,104 @@
+From 501a6b55853af549fae72723e74271f2a4ec7cf6 Mon Sep 17 00:00:00 2001
+From: Brett Warren <brett.warren@arm.com>
+Date: Fri, 27 Nov 2020 15:28:42 +0000
+Subject: [PATCH] arm/sysv: reverted clang VFP mitigation
+
+Since commit e3d2812ce43940aacae5bab2d0e965278cb1e7ea,
+seperate instructions were used when compiling under clang, 
+as clang didn't allow the directives at the time. This mitigation
+now causes compilation to fail under clang 10, as described by 
+https://github.com/libffi/libffi/issues/607. Now that
+clang supports the LDC and SDC instructions, this mitigation
+has been reverted.
+
+Upstream-Status: Pending
+Signed-off-by: Brett Warren <brett.warren@arm.com>
+---
+ src/arm/sysv.S | 33 ---------------------------------
+ 1 file changed, 33 deletions(-)
+
+diff --git a/src/arm/sysv.S b/src/arm/sysv.S
+index 63180a4..e3ce526 100644
+--- a/src/arm/sysv.S
++++ b/src/arm/sysv.S
+@@ -128,13 +128,8 @@ ARM_FUNC_START(ffi_call_VFP)
+        cfi_startproc
+ 
+        cmp     r3, #3                  @ load only d0 if possible
+-#ifdef __clang__
+-       vldrle d0, [sp]
+-       vldmgt sp, {d0-d7}
+-#else
+        ldcle   p11, cr0, [r0]          @ vldrle d0, [sp]
+        ldcgt   p11, cr0, [r0], {16}    @ vldmgt sp, {d0-d7}
+-#endif
+        add     r0, r0, #64             @ discard the vfp register args
+        /* FALLTHRU */
+ ARM_FUNC_END(ffi_call_VFP)
+@@ -172,25 +167,13 @@ ARM_FUNC_START(ffi_call_SYSV)
+        nop
+ 0:
+ E(ARM_TYPE_VFP_S)
+-#ifdef __clang__
+-       vstr s0, [r2]
+-#else
+        stc     p10, cr0, [r2]          @ vstr s0, [r2]
+-#endif
+        pop     {fp,pc}
+ E(ARM_TYPE_VFP_D)
+-#ifdef __clang__
+-       vstr d0, [r2]
+-#else
+        stc     p11, cr0, [r2]          @ vstr d0, [r2]
+-#endif
+        pop     {fp,pc}
+ E(ARM_TYPE_VFP_N)
+-#ifdef __clang__
+-       vstm r2, {d0-d3}
+-#else
+        stc     p11, cr0, [r2], {8}     @ vstm r2, {d0-d3}
+-#endif
+        pop     {fp,pc}
+ E(ARM_TYPE_INT64)
+        str     r1, [r2, #4]
+@@ -287,11 +270,7 @@ ARM_FUNC_START(ffi_closure_VFP)
+        add     ip, sp, #16
+        sub     sp, sp, #64+32                  @ allocate frame
+        cfi_adjust_cfa_offset(64+32)
+-#ifdef __clang__
+-       vstm sp, {d0-d7}
+-#else
+        stc     p11, cr0, [sp], {16}            @ vstm sp, {d0-d7}
+-#endif
+        stmdb   sp!, {ip,lr}
+ 
+        /* See above.  */
+@@ -320,25 +299,13 @@ ARM_FUNC_START_LOCAL(ffi_closure_ret)
+        cfi_rel_offset(lr, 4)
+ 0:
+ E(ARM_TYPE_VFP_S)
+-#ifdef __clang__
+-       vldr s0, [r2]
+-#else
+        ldc     p10, cr0, [r2]                  @ vldr s0, [r2]
+-#endif
+        ldm     sp, {sp,pc}
+ E(ARM_TYPE_VFP_D)
+-#ifdef __clang__
+-       vldr d0, [r2]
+-#else
+        ldc     p11, cr0, [r2]                  @ vldr d0, [r2]
+-#endif
+        ldm     sp, {sp,pc}
+ E(ARM_TYPE_VFP_N)
+-#ifdef __clang__
+-       vldm r2, {d0-d3}
+-#else
+        ldc     p11, cr0, [r2], {8}             @ vldm r2, {d0-d3}
+-#endif
+        ldm     sp, {sp,pc}
+ E(ARM_TYPE_INT64)
+        ldr     r1, [r2, #4]
+-- 
+2.17.1
+
diff --git a/meta/recipes-support/libffi/libffi_3.3.bb b/meta/recipes-support/libffi/libffi_3.3.bb
index 9dfdb9e39b..10ef003242 100644
--- a/meta/recipes-support/libffi/libffi_3.3.bb
+++ b/meta/recipes-support/libffi/libffi_3.3.bb
@@ -13,6 +13,7 @@ LIC_FILES_CHKSUM = "file://LICENSE;md5=492385fe22195952f5b9b197868ba268"
 SRC_URI = "https://github.com/libffi/libffi/releases/download/v${PV}/${BPN}-${PV}.tar.gz \
            file://not-win32.patch \
            file://0001-Fixed-missed-ifndef-for-__mips_soft_float.patch \
+           file://0001-arm-sysv-reverted-clang-VFP-mitigation.patch \
            file://0001-powerpc-fix-build-failure-on-power7-and-older-532.patch \
            file://0001-Address-platforms-with-no-__int128.patch \
            file://0001-Address-platforms-with-no-__int128-part2.patch \