Date: Sat, 06 May 2017 11:54:07 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 206990] powerpc (32-bit), projects/clang380-import vs. 11.0-CURRENT's sendsig: need to avoid signal delivery trashing the stack and so causing SIGSEGV Message-ID: <bug-206990-8-aQYit3pliJ@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-206990-8@https.bugs.freebsd.org/bugzilla/> References: <bug-206990-8@https.bugs.freebsd.org/bugzilla/>
next in thread | previous in thread | raw e-mail | index | archive | help
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D206990 --- Comment #8 from Mark Millard <markmi@dsl-only.net> --- (In reply to commit-hook from comment #7) It appears that this fix was necessary but not sufficient for TARGET_ARCH=3Dpowerpc . . . Bad news: Another code generation error, this time demonstrated in compiling part of perl5. . . (I tried to build a port that indirectly tried build perl5 but perl5's miniperl crashes.) /usr/obj/portswork/usr/ports/lang/perl5.24/work/perl-5.24.1/numeric.c has Perl_cast_iv(NV f) for which clang double stores two different things to one address [24(r1)]. Below the =3D> lines are the double store, the second destroying the r30 value that was saved in the first: Dump of assembler code for function Perl_cast_iv: 0x0196a114 <+0>: mflr r0 0x0196a118 <+4>: stw r0,4(r1) 0x0196a11c <+8>: stwu r1,-32(r1) 0x0196a120 <+12>: stw r31,28(r1) =3D> 0x0196a124 <+16>: stw r30,24(r1) 0x0196a128 <+20>: mr r31,r1 0x0196a12c <+24>: mfcr r12 =3D> 0x0196a130 <+28>: stw r12,24(r31) Note: r31 =3D=3D r1 for that second "=3D>" line. The return code sequence has a similar problem: two loads from the same address for what should be distinct values. Note: r31 =3D=3D r1 here too. =3D> 0x0196a1bc <+168>: lwz r12,24(r31) 0x0196a1c0 <+172>: lwz r0,36(r1) 0x0196a1c4 <+176>: lwz r31,28(r1) =3D> 0x0196a1c8 <+180>: lwz r30,24(r1) 0x0196a1cc <+184>: mtcrf 32,r12 0x0196a1d0 <+188>: addi r1,r1,32 0x0196a1d4 <+192>: mtlr r0 0x0196a1d8 <+196>: blr The Perl_cast_iv source code looks like: IV Perl_cast_iv(NV f) { if (f < IV_MAX_P1) return f < IV_MIN ? IV_MIN : (IV) f; if (f < UV_MAX_P1) { #if CASTFLAGS & 2 /* For future flexibility allowing for sizeof(UV) >=3D sizeof(IV) */ if (f < UV_MAX_P1_HALF) return (IV)(UV) f; f -=3D UV_MAX_P1_HALF; return (IV)(((UV) f) | (1 + (UV_MAX >> 1))); #else return (IV)(UV) f; #endif } return f > 0 ? (IV)UV_MAX : 0 /* NaN */; } I've reported this in llvm's bugzilla, reopening the report about ABI-stack-handling violations. --=20 You are receiving this mail because: You are the assignee for the bug.=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-206990-8-aQYit3pliJ>