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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - store happening to wrongly loaded address with thumb2"
href="https://bugs.llvm.org/show_bug.cgi?id=39919">39919</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>store happening to wrongly loaded address with thumb2
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>7.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>LLVM Codegen
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>raj.khem@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=21205" name="attach_21205" title="testcase">attachment 21205</a> <a href="attachment.cgi?id=21205&action=edit" title="testcase">[details]</a></span>
testcase
This issue pops up when compiling busybox for arm using thumb2 ISA. Getty
applet segfaults.
Program received signal SIGSEGV, Segmentation fault.
getty_main (argc=<optimized out>, argv=0x7efffd58) at loginutils/getty.c:561
warning: Source file is more recent than executable.
561 G.eol = '\r';
This is also present in the attached reproducer
clang -target armv7l-linux-gnueabihf -S -Os -mthumb getty.c
=====================================================
.code 16 @ @getty_main
.thumb_func
getty_main:
.fnstart
@ %bb.0:
.save {r4, r5, r6, r7, lr}
push {r4, r5, r6, r7, lr}
.setfp r7, sp, #12
add r7, sp, #12
.save {r11}
str r11, [sp, #-4]!
.pad #16
sub sp, #16
mov.w r0, #260
mov r6, r1
bl xzalloc <--------------------------- allocate ptr_to_globals
struct (return address of mem in r0)
ldr r2, .LCPI0_0
ldr r3, .LCPI0_1
.LPC0_0:
add r2, pc
ldr r5, .LCPI0_2
ldr r1, .LCPI0_3
.LPC0_1:
add r3, pc
ldr r4, [r2] <--------------------------- loads the address of
ptr_to_globals struct
.LPC0_2:
add r5, pc
str r0, [r2] <-------------------------- Stores the address
returned from xzalloc()
.LPC0_3:
add r1, pc
@APP
@NO_APP
str r3, [r0, #20]
add.w r2, r4, #20
str r5, [r0, #4]
movs r0, #13
strb.w r0, [r4, #68] <------------- Stores '\r' to globals+68 which is
location of ptr_to_globals.eol
adds r0, r4, #4
add.w r3, r4, #8
strd r2, r0, [sp]
add.w r2, r4, #16
mov r0, r6
str r4, [sp, #8]
bl getopt32
add sp, #16
ldr r11, [sp], #4
pop {r4, r5, r6, r7, pc}
.p2align 2
===============================================
As can be seen above, it has loaded address of ptr_to_globals into r4 before
return of xzalloc() in r0 is stored into it.</pre>
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