[Bug 33349] Use Thumb binaries on ARM?

[wine-bugs at winehq.org]

http://bugs.winehq.org/show_bug.cgi?id=33349

--- Comment #1 from Anastasius Focht <focht at gmx.net> 2013-04-12 16:50:51 CDT ---
Hello André,

as I told in earlier Wine/ARM bugs, Thumb-2 is the default for Win32 ARM PE
binaries.
Most ARM Linux distros (Debian, Ubuntu, Fedora?) use ARMv7-A + VFPv3-D16 +
Thumb-2 profile (Cortex-A).
So forcing Wine code to be compiled for ARM mode on these systems is not
optimal.

For the compiler flags, yes "-mthumb" would be sufficient, no need for
"-mthumb-interwork".
My toolchains have Thumb-2 as default profile, so there would be no need for
any CFLAGS override.

Building Wine as thumb code causes issues for "naked" functions with explicit
".arm" directive because the linker won't insert ARM-Thumb interworking veneers
automatically.
Raising "unimplemented API" exception currently fails because of that:

--- snip ---
Wine-gdb> bt
#0  0x4016970a in RtlRaiseException (rec=0x40c99310) at
/home/linaro/wine/wine-git/dlls/ntdll/signal_arm.c:1081
#1  0x401421b2 in stub_entry_point (dll=0x4ea2c4 "KERNEL32.dll", name=0x4eb05a
"InitOnceExecuteOnce", ret_addr=0x49c9b7)
    at /home/linaro/wine/wine-git/dlls/ntdll/loader.c:197
#2  0x0049c9b6 in ?? ()
#3  0x0049c9b6 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
Wine-gdb> p *rec
$1 = {ExceptionCode = 2147483904, ExceptionFlags = 1, ExceptionRecord = 0x0,
ExceptionAddress = 0x49c9b7, NumberParameters = 2, ExceptionInformation =
{5153476, 5156954, 
    1082964736, 5209840, 1075310241, 1075567040, 1082964736, 5209840,
1075310241, 4294967295, 1082642532, 1082642576, 0, 1086952288, 1074973151}} 
--- snip ---

RtlRaiseException as Thumb-2 code:

--- snip ---
Wine-gdb> disas
Dump of assembler code for function RtlRaiseException:
   0x401696fc <+0>:     push    {r7, lr}
   0x401696fe <+2>:     sub     sp, #88 ; 0x58
   0x40169700 <+4>:     add     r7, sp, #0
   0x40169702 <+6>:     str     r0, [r7, #4]
   0x40169704 <+8>:     add.w   r3, r7, #12
   0x40169708 <+12>:    mov     r0, r3
=> 0x4016970a <+14>:    bl      0x40168050 <RtlCaptureContext>
   0x4016970e <+18>:    ldr     r3, [r7, #76]   ; 0x4c
   0x40169710 <+20>:    mov     r2, r3
   0x40169712 <+22>:    ldr     r3, [r7, #4]
   0x40169714 <+24>:    str     r2, [r3, #12]
   0x40169716 <+26>:    add.w   r3, r7, #12
   0x4016971a <+30>:    ldr     r0, [r7, #4]
   0x4016971c <+32>:    mov     r1, r3
   0x4016971e <+34>:    mov.w   r2, #1
   0x40169722 <+38>:    bl      0x40168668 <raise_exception> 
...
--- snip ---

RtlCaptureContext is forced ARM code (naked, explicit ".arm" directive -> no
veneer to switch to arm mode):

--- snip ---
Wine-gdb> disas
Dump of assembler code for function RtlCaptureContext:
=> 0x40168050 <+0>:     push    {r1}
   0x40168054 <+4>:     mov     r1, #64 ; 0x40
   0x40168058 <+8>:     add     r1, r1, #3
   0x4016805c <+12>:    str     r1, [r0]
   0x40168060 <+16>:    pop     {r1}
   0x40168064 <+20>:    str     r0, [r0, #4]
   0x40168068 <+24>:    str     r1, [r0, #8]
   0x4016806c <+28>:    str     r2, [r0, #12]
   0x40168070 <+32>:    str     r3, [r0, #16]
   0x40168074 <+36>:    str     r4, [r0, #20] 
--- snip ---

T-bit set in CPSR (thumb mode):

--- snip ---
Wine-gdb> info reg
r0             0x40c992ac       1086952108
r1             0x4eb05a 5156954
r2             0x49c9b7 4835767
r3             0x40c992ac       1086952108
r4             0x415e0048       1096679496
r5             0x0      0
r6             0x0      0
r7             0x40c992a0       1086952096
r8             0x1      1
r9             0x0      0
r10            0x40     64
r11            0x40c99370       1086952304
r12            0x401a200c       1075453964
sp             0x40c992a0       0x40c992a0
lr             0x4016970f       1075222287
pc             0x40168050       0x40168050 <RtlCaptureContext>
cpsr           0x400f0030       1074724912  
--- snip ---

Wine source:
http://source.winehq.org/git/wine.git/blob/3c04958b8a47f56a6dfc9ac067ca88f34a4e29a2:/dlls/ntdll/signal_arm.c#l202

Removing ".arm" directive correctly raises the exception.

Regards

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