diff options
Diffstat (limited to 'dev-libs/libffi-compat/files/libffi-3.2.1-ia64-small-struct.patch')
| -rw-r--r-- | dev-libs/libffi-compat/files/libffi-3.2.1-ia64-small-struct.patch | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/dev-libs/libffi-compat/files/libffi-3.2.1-ia64-small-struct.patch b/dev-libs/libffi-compat/files/libffi-3.2.1-ia64-small-struct.patch new file mode 100644 index 000000000000..6e21f3566bc9 --- /dev/null +++ b/dev-libs/libffi-compat/files/libffi-3.2.1-ia64-small-struct.patch @@ -0,0 +1,74 @@ +From b58caef7fd620408be9239ac24ea89d5bc84f30b Mon Sep 17 00:00:00 2001 +From: Sergei Trofimovich <slyfox@gentoo.org> +Date: Sat, 17 Feb 2018 19:00:40 +0000 +Subject: [PATCH 2/2] ia64: fix small struct return + +This change fixes libffi.call/struct10.c failure on ia64: +FAIL: libffi.call/struct10.c -W -Wall -Wno-psabi -O0 execution test + +.Lst_small_struct handles returns for structs less than 32 bytes +(following ia64 return value ABI [1]). Subroutine does roughly the +following: + +``` + mov [sp+0] = r8 + mov [sp+8] = r9 + mov [sp+16] = r10 + mov [sp+24] = r11 + memcpy(destination, source=sp, 12); +``` + +The problem: ia64 ABI guarantees that top 16 bytes of stack are +scratch space for callee function. Thus it can clobber it. [1] +says (7.1 Procedure Frames): +""" +* Scratch area. This 16-byte region is provided as scratch storage + for procedures that are called by the current procedure. Leaf + procedures do not need to allocate this region. A procedure may + use the 16 bytes at the top of its own frame as scratch memory, + but the contents of this area are not preserved by a procedure call. +""" + +In our case 16 top bytes are clobbered by a PLT resolver when memcpy() +is called for the first time. As a result memcpy implementation reads +already clobbered data frop top of stack. + +The fix is simple: allocate 16 bytes of scrats space prior to memcpy() +call. + +[1]: https://www.intel.com/content/dam/www/public/us/en/documents/guides/itanium-software-runtime-architecture-guide.pdf + +Bug: https://bugs.gentoo.org/634190 +Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> +--- + src/ia64/unix.S | 7 ++++++- + 1 file changed, 6 insertions(+), 1 deletion(-) + +diff --git a/src/ia64/unix.S b/src/ia64/unix.S +index 4733377..e2547e0 100644 +--- a/src/ia64/unix.S ++++ b/src/ia64/unix.S +@@ -175,7 +175,6 @@ ffi_call_unix: + ;; + + .Lst_small_struct: +- add sp = -16, sp + cmp.lt p6, p0 = 8, in3 + cmp.lt p7, p0 = 16, in3 + cmp.lt p8, p0 = 24, in3 +@@ -191,6 +190,12 @@ ffi_call_unix: + (p8) st8 [r18] = r11 + mov out1 = sp + mov out2 = in3 ++ ;; ++ // ia64 software calling convention requires ++ // top 16 bytes of stack to be scratch space ++ // PLT resolver uses that scratch space at ++ // 'memcpy' symbol reolution time ++ add sp = -16, sp + br.call.sptk.many b0 = memcpy# + ;; + mov ar.pfs = loc0 +-- +2.16.1 + |