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-rw-r--r--contrib/guix/manifest.scm7
-rw-r--r--contrib/guix/patches/gcc-broken-longjmp.patch68
2 files changed, 72 insertions, 3 deletions
diff --git a/contrib/guix/manifest.scm b/contrib/guix/manifest.scm
index 5bf8949c37..11bfe80b1d 100644
--- a/contrib/guix/manifest.scm
+++ b/contrib/guix/manifest.scm
@@ -166,9 +166,10 @@ desirable for building Bitcoin Core release binaries."
(define (make-gcc-without-newlib gcc)
(package-with-extra-configure-variable gcc "--with-newlib" "no"))
-(define (make-mingw-w64-cross-gcc-vmov-alignment cross-gcc)
+(define (make-mingw-w64-cross-gcc cross-gcc)
(package-with-extra-patches cross-gcc
- (search-our-patches "vmov-alignment.patch")))
+ (search-our-patches "vmov-alignment.patch"
+ "gcc-broken-longjmp.patch")))
(define (make-mingw-pthreads-cross-toolchain target)
"Create a cross-compilation toolchain package for TARGET"
@@ -176,7 +177,7 @@ desirable for building Bitcoin Core release binaries."
(pthreads-xlibc mingw-w64-x86_64-winpthreads)
(pthreads-xgcc (make-gcc-with-pthreads
(cross-gcc target
- #:xgcc (make-gcc-without-newlib (make-ssp-fixed-gcc (make-mingw-w64-cross-gcc-vmov-alignment base-gcc)))
+ #:xgcc (make-gcc-without-newlib (make-ssp-fixed-gcc (make-mingw-w64-cross-gcc base-gcc)))
#:xbinutils xbinutils
#:libc pthreads-xlibc))))
;; Define a meta-package that propagates the resulting XBINUTILS, XLIBC, and
diff --git a/contrib/guix/patches/gcc-broken-longjmp.patch b/contrib/guix/patches/gcc-broken-longjmp.patch
new file mode 100644
index 0000000000..1cfc0918b0
--- /dev/null
+++ b/contrib/guix/patches/gcc-broken-longjmp.patch
@@ -0,0 +1,68 @@
+commit eb5698897c52702498938592d7f76e67d126451f
+Author: Eric Botcazou <ebotcazou@adacore.com>
+Date: Wed May 5 22:48:51 2021 +0200
+
+ Fix PR target/100402
+
+ This is a regression for 64-bit Windows present from mainline down to the 9
+ branch and introduced by the fix for PR target/99234. Again SEH, but with
+ a twist related to the way MinGW implements setjmp/longjmp, which turns out
+ to be piggybacked on SEH with recent versions of MinGW, i.e. the longjmp
+ performs a bona-fide unwinding of the stack, because it calls RtlUnwindEx
+ with the second argument initially passed to setjmp, which is the result of
+ __builtin_frame_address (0) in the MinGW header file:
+
+ define setjmp(BUF) _setjmp((BUF), __builtin_frame_address (0))
+
+ This means that we directly expose the frame pointer to the SEH machinery
+ here (unlike with regular exception handling where we use an intermediate
+ CFA) and thus that we cannot do whatever we want with it. The old code
+ would leave it unaligned, i.e. not multiple of 16, whereas the new code
+ aligns it, but this breaks for some reason; at least it appears that a
+ .seh_setframe directive with 0 as second argument always works, so the
+ fix aligns it this way.
+
+ gcc/
+ PR target/100402
+ * config/i386/i386.c (ix86_compute_frame_layout): For a SEH target,
+ always return the establisher frame for __builtin_frame_address (0).
+ gcc/testsuite/
+ * gcc.c-torture/execute/20210505-1.c: New test.
+
+diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
+index 2f838840e96..06ad1b2274e 100644
+--- a/gcc/config/i386/i386.c
++++ b/gcc/config/i386/i386.c
+@@ -6356,12 +6356,29 @@ ix86_compute_frame_layout (void)
+ area, see the SEH code in config/i386/winnt.c for the rationale. */
+ frame->hard_frame_pointer_offset = frame->sse_reg_save_offset;
+
+- /* If we can leave the frame pointer where it is, do so. Also, return
++ /* If we can leave the frame pointer where it is, do so; however return
+ the establisher frame for __builtin_frame_address (0) or else if the
+- frame overflows the SEH maximum frame size. */
++ frame overflows the SEH maximum frame size.
++
++ Note that the value returned by __builtin_frame_address (0) is quite
++ constrained, because setjmp is piggybacked on the SEH machinery with
++ recent versions of MinGW:
++
++ # elif defined(__SEH__)
++ # if defined(__aarch64__) || defined(_ARM64_)
++ # define setjmp(BUF) _setjmp((BUF), __builtin_sponentry())
++ # elif (__MINGW_GCC_VERSION < 40702)
++ # define setjmp(BUF) _setjmp((BUF), mingw_getsp())
++ # else
++ # define setjmp(BUF) _setjmp((BUF), __builtin_frame_address (0))
++ # endif
++
++ and the second argument passed to _setjmp, if not null, is forwarded
++ to the TargetFrame parameter of RtlUnwindEx by longjmp (after it has
++ built an ExceptionRecord on the fly describing the setjmp buffer). */
+ const HOST_WIDE_INT diff
+ = frame->stack_pointer_offset - frame->hard_frame_pointer_offset;
+- if (diff <= 255)
++ if (diff <= 255 && !crtl->accesses_prior_frames)
+ {
+ /* The resulting diff will be a multiple of 16 lower than 255,
+ i.e. at most 240 as required by the unwind data structure. */