[LLVMbugs] [Bug 22015] New: post-RA scheduler breaks unwinding through indirect calls
bugzilla-daemon at llvm.org
bugzilla-daemon at llvm.org
Tue Dec 23 05:50:01 PST 2014
http://llvm.org/bugs/show_bug.cgi?id=22015
Bug ID: 22015
Summary: post-RA scheduler breaks unwinding through indirect
calls
Product: libraries
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: Backend: PowerPC
Assignee: unassignedbugs at nondot.org
Reporter: jay.foad at gmail.com
CC: llvmbugs at cs.uiuc.edu
Classification: Unclassified
Created attachment 13588
--> http://llvm.org/bugs/attachment.cgi?id=13588&action=edit
test case
With the attached test case I get:
$ llc -O2 -o - a.ll
[...]
f: # @f
.align 3
.quad .L.f
.quad .TOC. at tocbase
.quad 0
.text
.L.f:
.cfi_startproc
# BB#0:
mflr 0
std 0, 16(1)
stdu 1, -128(1)
.Ltmp0:
.cfi_def_cfa_offset 128
.Ltmp1:
.cfi_offset lr, 16
.Ltmp2:
.cfi_offset r30, -16
addis 4, 2, .LC1 at toc@ha
std 30, 112(1) # 8-byte Folded Spill
mr 30, 3
ori 2, 2, 0
ld 4, .LC1 at toc@l(4)
ld 12, 0(4)
std 2, 40(1)
ori 2, 2, 0
ld 4, 0(12)
ld 11, 16(12)
ld 2, 8(12)
mtctr 4
bctrl
mr 3, 30
ld 2, 40(1)
[...]
At this point, just after the indirect call to *g, the TOC pointer is reloaded
from the stack into r2. The problem is that the system unwinder in libgcc only
recognises this if the "ld r2,40(r1)" instruction is *immediately* after the
call instruction. In this case the post-RA scheduler has moved things around so
that it is not.
This breaks a bunch of asan test cases on PowerPC64 when the asan runtime is
built with clang, because asan's __interceptor___cxa_throw is affected by the
bug.
AddressSanitizer-Unit ::
Asan-powerpc64-inline-Test/AddressSanitizer.CxxExceptionTest
AddressSanitizer-Unit ::
Asan-powerpc64-with-calls-Test/AddressSanitizer.CxxExceptionTest
AddressSanitizer-Unit ::
Asan-powerpc64le-inline-Test/AddressSanitizer.CxxExceptionTest
AddressSanitizer-Unit ::
Asan-powerpc64le-with-calls-Test/AddressSanitizer.CxxExceptionTest
AddressSanitizer64 :: TestCases/contiguous_container.cc
AddressSanitizer64 :: TestCases/throw_call_test.cc
AddressSanitizer64 :: TestCases/throw_catch.cc
AddressSanitizer64 :: TestCases/uar_and_exceptions.cc
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