aarch64 callVirtualFunction needs to be compiled w/o -fstack-clash-protection

At least when doing an aarch64 Flatpak build against org.freedesktop.Sdk//19.08,
which uses GCC 9.2.0 and passes in `CXXFLAGS=-O2 -g -pipe
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
-fstack-protector-strong -grecord-gcc-switches -fasynchronous-unwind-tables
-fstack-clash-protection`, callVirtualMethod (in
bridges/source/cpp_uno/gcc3_linux_aarch64/callvirtualfunction.cxx) would
decrement the stack pointer another 16 bytes after the

stackargs = alloca(...);

and before the asm block, so in the called virtual function, arguments read from
the stack would read garbage (and CustomTarget_testtools/uno_test would fail
with SIGSEGV at

> #0  0x0000ffffb733eb48 in rtl::OUString::operator= (this=0xaaaaf9c1ac30, str=...) at /run/build/libreoffice/include/rtl/ustring.hxx:453
> #1  0x0000ffffb733a7bc in bridge_object::assign (rData=..., bBool=true, cChar=64 u'@', nByte=17 '\021', nShort=4660, nUShort=65244, nLong=305419896, nULong=4275878552, nHyper=0, nUHyper=187651311381888, fFloat=17.0814991, fDouble=3.1415926358999999, eEnum=-1698898192, rStr=..., xTest=..., rAny=...) at /run/build/libreoffice/testtools/source/bridgetest/cppobj.cxx:99
> #2  0x0000ffffb733a87c in bridge_object::assign (rData=..., bBool=true, cChar=64 u'@', nByte=17 '\021', nShort=4660, nUShort=65244, nLong=305419896, nULong=4275878552, nHyper=0, nUHyper=187651311381888, fFloat=17.0814991, fDouble=3.1415926358999999, eEnum=-1698898192, rStr=..., xTest=..., rAny=..., rSequence=...) at /run/build/libreoffice/testtools/source/bridgetest/cppobj.cxx:115
> #3  0x0000ffffb733ade4 in bridge_object::Test_Impl::setValues (this=0xaaaaf9c1abb0, bBool=1 '\001', cChar=64 u'@', nByte=17 '\021', nShort=4660, nUShort=65244, nLong=305419896, nULong=4275878552, nHyper=0, nUHyper=187651311381888, fFloat=17.0814991, fDouble=3.1415926358999999, eEnum=-1698898192, rStr=..., xTest=..., rAny=..., rSequence=..., rStruct=...) at /run/build/libreoffice/testtools/source/bridgetest/cppobj.cxx:548
> #4  0x0000ffffb740bff4 in callVirtualFunction (function=281473755360772, gpr=0xffffd1ab1f28, fpr=0xffffd1ab1f68, stack=0xffffd1ab1d40, sp=8, ret=0xffffd1ab22c0) at /run/build/libreoffice/bridges/source/cpp_uno/gcc3_linux_aarch64/callvirtualfunction.cxx:63
> #5  0x0000ffffb740ca70 in (anonymous namespace)::call (proxy=0xaaaaf9c291c0, slot=..., returnType=0xaaaaf9c00770, count=17, parameters=0xaaaaf9c3a210, returnValue=0xffffd1ab22c0, arguments=0xffffd1ab2230, exception=0xffffd1ab2370) at /run/build/libreoffice/bridges/source/cpp_uno/gcc3_linux_aarch64/uno2cpp.cxx:178
> #6  0x0000ffffb740d4c4 in bridges::cpp_uno::shared::unoInterfaceProxyDispatch (pUnoI=0xaaaaf9c291c0, pMemberDescr=0xaaaaf9c55950, pReturn=0xffffd1ab22c0, pArgs=0xffffd1ab2230, ppException=0xffffd1ab2370) at /run/build/libreoffice/bridges/source/cpp_uno/gcc3_linux_aarch64/uno2cpp.cxx:361
> #7  0x0000ffffb740720c in (anonymous namespace)::call (proxy=0xaaaaf9c549c0, description=..., returnType=0xaaaaf9c00770, count=17, parameters=0xaaaaf9c3a210, gpr=0xffffd1ab2510, fpr=0xffffd1ab2550, stack=0xffffd1ab2590, indirectRet=0xffffb7d24790) at /run/build/libreoffice/bridges/source/cpp_uno/gcc3_linux_aarch64/cpp2uno.cxx:120
> #8  0x0000ffffb74079a0 in (anonymous namespace)::vtableCall (functionIndex=40, vtableOffset=0, gpr=0xffffd1ab2510, fpr=0xffffd1ab2550, stack=0xffffd1ab2590, indirectRet=0xffffb7d24790) at /run/build/libreoffice/bridges/source/cpp_uno/gcc3_linux_aarch64/cpp2uno.cxx:291
> #9  0x0000ffffb7407b00 in (anonymous namespace)::vtableSlotCall (gpr0=187651311618536, gpr1=1, gpr2=64, gpr3=17, gpr4=4660, gpr5=65244, gpr6=305419896, gpr7=4275878552, fpr0=5.4321266044931319e-315, fpr1=3.1415926358999999, fpr2=0, fpr3=4.0039072046065485, fpr4=0, fpr5=4.003911019303815, fpr6=8.9589789687541617e+102, fpr7=-4.4588500238274385e-308) at /run/build/libreoffice/bridges/source/cpp_uno/gcc3_linux_aarch64/cpp2uno.cxx:348
> #10 0x0000ffffb739e60c in bridge_test::performTest (xContext=..., xLBT=..., noCurrentContext=false) at /run/build/libreoffice/testtools/source/bridgetest/bridgetest.cxx:378
> #11 0x0000ffffb73a3d58 in bridge_test::TestBridgeImpl::run (this=0xaaaaf9c18550, rArgs=...) at /run/build/libreoffice/testtools/source/bridgetest/bridgetest.cxx:1162
> #12 0x0000aaaad292a3ec in sal_main () at /run/build/libreoffice/cpputools/source/unoexe/unoexe.cxx:509
> #13 0x0000aaaad29297a0 in main (argc=8, argv=0xffffd1ab31b8) at /run/build/libreoffice/cpputools/source/unoexe/unoexe.cxx:349

.)

By experiment, I found the problematic thing to be -fstack-clash-protection,
which can apparently be cancelled with a subsequent -fno-stack-clash-protection
at least on that GCC 9.2.0.  (And -f[no-]stack-clash-protection appears to only
be available since GCC 8, and not at all for Clang, so check for it with
HAVE_GCC_STACK_CLASH_PROTECTION.)

Change-Id: If667fdf704b1ba20a04593b38d2d1f079280df41
Reviewed-on: https://gerrit.libreoffice.org/80701
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/bridges/Library_cpp_uno.mk b/bridges/Library_cpp_uno.mk
index f9e573bd7ff2..277c54cf79dc 100644
--- a/bridges/Library_cpp_uno.mk
+++ b/bridges/Library_cpp_uno.mk
@@ -30,7 +30,12 @@ else ifeq ($(CPUNAME),AARCH64)
 
 ifneq ($(filter ANDROID DRAGONFLY FREEBSD LINUX NETBSD OPENBSD,$(OS)),)
 bridges_SELECTED_BRIDGE := gcc3_linux_aarch64
-bridge_exception_objects := abi callvirtualfunction uno2cpp
+bridge_exception_objects := abi uno2cpp
+
+$(eval $(call gb_Library_add_exception_objects,$(gb_CPPU_ENV)_uno, \
+    bridges/source/cpp_uno/$(bridges_SELECTED_BRIDGE)/callvirtualfunction, \
+    $(if $(HAVE_GCC_STACK_CLASH_PROTECTION),-fno-stack-clash-protection) \
+))
 
 $(eval $(call gb_Library_add_exception_objects,$(gb_CPPU_ENV)_uno, \
     bridges/source/cpp_uno/$(bridges_SELECTED_BRIDGE)/cpp2uno, \