Oops, you are correct, I read the code too quickly and didn't notice
the #endif right after the Thumb bit cancellation (I thought the
function didn't return any value when on ARM).
A white line before #if defined(__powerpc__) would help readability :-)
Forget that part.
Thanks,
Christophe.
On 7 May 2013 09:44, Evgeniy Stepanov <euge...@google.com> wrote:
> On Tue, May 7, 2013 at 9:33 AM, Konstantin Serebryany
> <konstantin.s.serebry...@gmail.com> wrote:
>> +euge...@google.com (our ARM expert)
>>
>> Christophe,
>>
>> The change in sanitizer_common/sanitizer_stacktrace.cc changes the
>> logic which is known to work well for us on Android/ARM.
>> I'd like Evgeniy to comment on it.
>>
>> --kcc
>>
>> On Mon, May 6, 2013 at 10:52 PM, Christophe Lyon
>> <christophe.l...@linaro.org> wrote:
>>> Hi,
>>>
>>> Here is a 2nd attempt at enabling libsanitizer on ARM.
>>> Compared with the previous version, this patch is more intrusive to
>>> workaround some limitations with qemu:
>>>
>>> * qemu does not work well with threads, so I chose to disable
>>> clone-test-1.c and rlimit-mmap-test-1.c when running on a simulator.
>>> This is a bit overkill since the limitation is caused by qemu, not by
>>> the fact of running on a simulator. Would it cause problems on other
>>> targets?
>>>
>>> * due to different connexion mathod between runtest and the target
>>> program in native mode and in simulated mode, causing isatty(2) to
>>> give a different answer, I modified a few regexps to accept possible
>>> decorations. This can be removed once ASAN_OPTIONS=color=0 is
>>> implemented.
>>>
>>> Tested on x86 with no regression, on ARM cortex-a9 hardware and
>>> a15-qemu with the expected new tests.
>>>
>>> OK?
>>>
>>> Christophe.
>>>
>>> 2013-05-06 Christophe Lyon <christophe.l...@linaro.org>
>>>
>>> gcc/
>>> * config/arm/arm.c (arm_asan_shadow_offset): New function.
>>> (TARGET_ASAN_SHADOW_OFFSET): Define.
>>> * config/arm/linux-eabi.h (ASAN_CC1_SPEC): Define.
>>> (LINUX_OR_ANDROID_CC): Add ASAN_CC1_SPEC.
>>>
>>> libsanitizer/
>>> * configure.tgt: Add ARM pattern.
>>> * sanitizer_common/sanitizer_stacktrace.cc: Return the computed
>>> value.
>>>
>>> testsuite/
>>> * lib/target-supports.exp (check_effective_target_hw): New
>>> function.
>>> * c-c++-common/asan/clone-test-1.c: Call
>>> check_effective_target_hw.
>>> * c-c++-common/asan/rlimit-mmap-test-1.c: Likewise.
>>> * c-c++-common/asan/heap-overflow-1.c: Update regexps to accept
>>> possible decorations.
>>> * c-c++-common/asan/null-deref-1.c: Likewise.
>>> * c-c++-common/asan/stack-overflow-1.c: Likewise.
>>> * c-c++-common/asan/strncpy-overflow-1.c: Likewise.
>>> * c-c++-common/asan/use-after-free-1.c: Likewise.
>>> * g++.dg/asan/deep-thread-stack-1.C: Likewise.
>>> * g++.dg/asan/large-func-test-1.C: Likewise.
>>>
>>> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
>>> index 0b97cf8..c036a21 100644
>>> --- a/gcc/config/arm/arm.c
>>> +++ b/gcc/config/arm/arm.c
>>> @@ -281,6 +281,8 @@ static unsigned arm_add_stmt_cost (void *data, int
>>> count,
>>>
>>> static void arm_canonicalize_comparison (int *code, rtx *op0, rtx *op1,
>>> bool op0_preserve_value);
>>> +static unsigned HOST_WIDE_INT arm_asan_shadow_offset (void);
>>> +
>>>
>>> /* Table of machine attributes. */
>>> static const struct attribute_spec arm_attribute_table[] =
>>> @@ -657,6 +659,9 @@ static const struct attribute_spec
>>> arm_attribute_table[] =
>>> #define TARGET_CANONICALIZE_COMPARISON \
>>> arm_canonicalize_comparison
>>>
>>> +#undef TARGET_ASAN_SHADOW_OFFSET
>>> +#define TARGET_ASAN_SHADOW_OFFSET arm_asan_shadow_offset
>>> +
>>> struct gcc_target targetm = TARGET_INITIALIZER;
>>>
>>> /* Obstack for minipool constant handling. */
>>> @@ -28062,4 +28067,12 @@ arm_validize_comparison (rtx *comparison, rtx
>>> * op1, rtx * op2)
>>>
>>> }
>>>
>>> +/* Implement the TARGET_ASAN_SHADOW_OFFSET hook. */
>>> +
>>> +static unsigned HOST_WIDE_INT
>>> +arm_asan_shadow_offset (void)
>>> +{
>>> + return (unsigned HOST_WIDE_INT) 1 << 29;
>>> +}
>>> +
>>> #include "gt-arm.h"
>>> diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
>>> index 23671a7..cb0aad1 100644
>>> --- a/gcc/config/arm/linux-eabi.h
>>> +++ b/gcc/config/arm/linux-eabi.h
>>> @@ -84,10 +84,14 @@
>>> LINUX_OR_ANDROID_LD (LINUX_TARGET_LINK_SPEC, \
>>> LINUX_TARGET_LINK_SPEC " " ANDROID_LINK_SPEC)
>>>
>>> +#undef ASAN_CC1_SPEC
>>> +#define ASAN_CC1_SPEC "%{fsanitize=*:-funwind-tables}"
>>> +
>>> #undef CC1_SPEC
>>> #define CC1_SPEC \
>>> - LINUX_OR_ANDROID_CC (GNU_USER_TARGET_CC1_SPEC, \
>>> - GNU_USER_TARGET_CC1_SPEC " " ANDROID_CC1_SPEC)
>>> + LINUX_OR_ANDROID_CC (GNU_USER_TARGET_CC1_SPEC " " ASAN_CC1_SPEC, \
>>> + GNU_USER_TARGET_CC1_SPEC " " ASAN_CC1_SPEC " " \
>>> + ANDROID_CC1_SPEC)
>>>
>>> #define CC1PLUS_SPEC \
>>> LINUX_OR_ANDROID_CC ("", ANDROID_CC1PLUS_SPEC)
>>> diff --git a/gcc/testsuite/c-c++-common/asan/clone-test-1.c
>>> b/gcc/testsuite/c-c++-common/asan/clone-test-1.c
>>> index d9acc0d..fd187aa 100644
>>> --- a/gcc/testsuite/c-c++-common/asan/clone-test-1.c
>>> +++ b/gcc/testsuite/c-c++-common/asan/clone-test-1.c
>>> @@ -3,6 +3,7 @@
>>>
>>> /* { dg-do run { target { *-*-linux* } } } */
>>> /* { dg-require-effective-target clone } */
>>> +/* { dg-require-effective-target hw } */
>>> /* { dg-options "-D_GNU_SOURCE" } */
>>>
>>> #include <stdio.h>
>>> diff --git a/gcc/testsuite/c-c++-common/asan/heap-overflow-1.c
>>> b/gcc/testsuite/c-c++-common/asan/heap-overflow-1.c
>>> index 43d47a3..e0b9038 100644
>>> --- a/gcc/testsuite/c-c++-common/asan/heap-overflow-1.c
>>> +++ b/gcc/testsuite/c-c++-common/asan/heap-overflow-1.c
>>> @@ -25,7 +25,7 @@ int main(int argc, char **argv) {
>>>
>>> /* { dg-output "READ of size 1 at 0x\[0-9a-f\]+ thread T0.*(\n|\r\n|\r)" }
>>> */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*heap-overflow-1.c:21|\[^\n\r]*:0)|\[(\]).*(\n|\r\n|\r)" } */
>>> -/* { dg-output "0x\[0-9a-f\]+ is located 0 bytes to the right of
>>> 10-byte region\[^\n\r]*(\n|\r\n|\r)" } */
>>> -/* { dg-output "allocated by thread T0 here:\[^\n\r]*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*0x\[0-9a-f\]+ is located 0 bytes to the right of
>>> 10-byte region\[^\n\r]*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*allocated by thread T0 here:\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in
>>> _*(interceptor_|)malloc|\[(\])\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #1 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*heap-overflow-1.c:19|\[^\n\r]*:0)|\[(\])\[^\n\r]*(\n|\r\n|\r)"
>>> } */
>>> diff --git a/gcc/testsuite/c-c++-common/asan/null-deref-1.c
>>> b/gcc/testsuite/c-c++-common/asan/null-deref-1.c
>>> index 2eee986..95e5036 100644
>>> --- a/gcc/testsuite/c-c++-common/asan/null-deref-1.c
>>> +++ b/gcc/testsuite/c-c++-common/asan/null-deref-1.c
>>> @@ -18,6 +18,6 @@ int main()
>>>
>>> /* { dg-output "ERROR: AddressSanitizer:? SEGV on unknown
>>> address\[^\n\r]*" } */
>>> /* { dg-output "0x\[0-9a-f\]+ \[^\n\r]*pc
>>> 0x\[0-9a-f\]+\[^\n\r]*(\n|\r\n|\r)" } */
>>> -/* { dg-output "AddressSanitizer can not provide additional
>>> info.*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*AddressSanitizer can not provide additional
>>> info.*(\n|\r\n|\r)" } */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in \[^\n\r]*NullDeref\[^\n\r]*
>>> (\[^\n\r]*null-deref-1.c:10|\[^\n\r]*:0)|\[(\])\[^\n\r]*(\n|\r\n|\r)"
>>> } */
>>> /* { dg-output " #1 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*null-deref-1.c:15|\[^\n\r]*:0)|\[(\])\[^\n\r]*(\n|\r\n|\r)"
>>> } */
>>> diff --git a/gcc/testsuite/c-c++-common/asan/rlimit-mmap-test-1.c
>>> b/gcc/testsuite/c-c++-common/asan/rlimit-mmap-test-1.c
>>> index 0b3d2ae..9dbbc85 100644
>>> --- a/gcc/testsuite/c-c++-common/asan/rlimit-mmap-test-1.c
>>> +++ b/gcc/testsuite/c-c++-common/asan/rlimit-mmap-test-1.c
>>> @@ -2,6 +2,7 @@
>>>
>>> /* { dg-do run { target setrlimit } } */
>>> /* { dg-skip-if "" { *-*-* } { "*" } { "-O0" } } */
>>> +/* { dg-require-effective-target hw } */
>>> /* { dg-shouldfail "asan" } */
>>>
>>> #include <stdlib.h>
>>> diff --git a/gcc/testsuite/c-c++-common/asan/stack-overflow-1.c
>>> b/gcc/testsuite/c-c++-common/asan/stack-overflow-1.c
>>> index 790aa5e..5788b10 100644
>>> --- a/gcc/testsuite/c-c++-common/asan/stack-overflow-1.c
>>> +++ b/gcc/testsuite/c-c++-common/asan/stack-overflow-1.c
>>> @@ -19,4 +19,4 @@ int main() {
>>>
>>> /* { dg-output "READ of size 1 at 0x\[0-9a-f\]+ thread
>>> T0\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*stack-overflow-1.c:16|\[^\n\r]*:0)|\[(\]).*(\n|\r\n|\r)" }
>>> */
>>> -/* { dg-output "Address 0x\[0-9a-f\]+ is\[^\n\r]*frame <main>" } */
>>> +/* { dg-output ".*Address 0x\[0-9a-f\]+ is\[^\n\r]*frame <main>" } */
>>> diff --git a/gcc/testsuite/c-c++-common/asan/strncpy-overflow-1.c
>>> b/gcc/testsuite/c-c++-common/asan/strncpy-overflow-1.c
>>> index 10b3ad7..5e8ce40 100644
>>> --- a/gcc/testsuite/c-c++-common/asan/strncpy-overflow-1.c
>>> +++ b/gcc/testsuite/c-c++-common/asan/strncpy-overflow-1.c
>>> @@ -15,7 +15,7 @@ int main(int argc, char **argv) {
>>> /* { dg-output "WRITE of size \[0-9\]* at 0x\[0-9a-f\]+ thread
>>> T0\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in
>>> _*(interceptor_|)strncpy|\[(\])\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #1 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*strncpy-overflow-1.c:11|\[^\n\r]*:0)|\[(\]).*(\n|\r\n|\r)" }
>>> */
>>> -/* { dg-output "0x\[0-9a-f\]+ is located 0 bytes to the right of
>>> 9-byte region\[^\n\r]*(\n|\r\n|\r)" } */
>>> -/* { dg-output "allocated by thread T0 here:\[^\n\r]*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*0x\[0-9a-f\]+ is located 0 bytes to the right of
>>> 9-byte region\[^\n\r]*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*allocated by thread T0 here:\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in
>>> _*(interceptor_|)malloc|\[(\])\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #1 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*strncpy-overflow-1.c:10|\[^\n\r]*:0)|\[(\])\[^\n\r]*(\n|\r\n|\r)"
>>> } */
>>> diff --git a/gcc/testsuite/c-c++-common/asan/use-after-free-1.c
>>> b/gcc/testsuite/c-c++-common/asan/use-after-free-1.c
>>> index 939feeb..65318c8 100644
>>> --- a/gcc/testsuite/c-c++-common/asan/use-after-free-1.c
>>> +++ b/gcc/testsuite/c-c++-common/asan/use-after-free-1.c
>>> @@ -11,12 +11,12 @@ int main() {
>>>
>>> /* { dg-output "ERROR: AddressSanitizer:? heap-use-after-free on
>>> address\[^\n\r]*" } */
>>> /* { dg-output "0x\[0-9a-f\]+ at pc 0x\[0-9a-f\]+ bp 0x\[0-9a-f\]+ sp
>>> 0x\[0-9a-f\]+\[^\n\r]*(\n|\r\n|\r)" } */
>>> -/* { dg-output "READ of size 1 at 0x\[0-9a-f\]+ thread
>>> T0\[^\n\r]*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*READ of size 1 at 0x\[0-9a-f\]+ thread
>>> T0\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*use-after-free-1.c:9|\[^\n\r]*:0)|\[(\]).*(\n|\r\n|\r)" } */
>>> -/* { dg-output "0x\[0-9a-f\]+ is located 5 bytes inside of 10-byte
>>> region .0x\[0-9a-f\]+,0x\[0-9a-f\]+\[^\n\r]*(\n|\r\n|\r)" } */
>>> -/* { dg-output "freed by thread T0 here:\[^\n\r]*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*0x\[0-9a-f\]+ is located 5 bytes inside of 10-byte
>>> region .0x\[0-9a-f\]+,0x\[0-9a-f\]+\[^\n\r]*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*freed by thread T0 here:\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in
>>> _*(interceptor_|)free|\[(\])\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #1 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*use-after-free-1.c:8|\[^\n\r]*:0)|\[(\]).*(\n|\r\n|\r)" } */
>>> -/* { dg-output "previously allocated by thread T0
>>> here:\[^\n\r]*(\n|\r\n|\r)" } */
>>> +/* { dg-output ".*previously allocated by thread T0
>>> here:\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #0 0x\[0-9a-f\]+ (in
>>> _*(interceptor_|)malloc|\[(\])\[^\n\r]*(\n|\r\n|\r)" } */
>>> /* { dg-output " #1 0x\[0-9a-f\]+ (in _*main
>>> (\[^\n\r]*use-after-free-1.c:7|\[^\n\r]*:0)|\[(\])\[^\n\r]*(\n|\r\n|\r)"
>>> } */
>>> diff --git a/gcc/testsuite/g++.dg/asan/deep-thread-stack-1.C
>>> b/gcc/testsuite/g++.dg/asan/deep-thread-stack-1.C
>>> index 12d8a7a..d29fe31 100644
>>> --- a/gcc/testsuite/g++.dg/asan/deep-thread-stack-1.C
>>> +++ b/gcc/testsuite/g++.dg/asan/deep-thread-stack-1.C
>>> @@ -45,9 +45,9 @@ int main(int argc, char *argv[]) {
>>> }
>>>
>>> // { dg-output "ERROR: AddressSanitizer:
>>> heap-use-after-free.*(\n|\r\n|\r)" }
>>> -// { dg-output "WRITE of size 4 at 0x\[0-9a-f\]+ thread
>>> T(\[0-9\]+).*(\n|\r\n|\r)" }
>>> -// { dg-output "freed by thread T(\[0-9\]+) here:.*(\n|\r\n|\r)" }
>>> -// { dg-output "previously allocated by thread T(\[0-9\]+)
>>> here:.*(\n|\r\n|\r)" }
>>> +// { dg-output ".*WRITE of size 4 at 0x\[0-9a-f\]+ thread
>>> T(\[0-9\]+).*(\n|\r\n|\r)" }
>>> +// { dg-output ".*freed by thread T(\[0-9\]+) here:.*(\n|\r\n|\r)" }
>>> +// { dg-output ".*previously allocated by thread T(\[0-9\]+)
>>> here:.*(\n|\r\n|\r)" }
>>> // { dg-output "Thread T\\2 created by T(\[0-9\]+) here:.*(\n|\r\n|\r)" }
>>> // { dg-output "Thread T\\8 created by T0 here:.*(\n|\r\n|\r)" }
>>> // { dg-output "Thread T\\4 created by T(\[0-9\]+) here:.*(\n|\r\n|\r)" }
>>> diff --git a/gcc/testsuite/g++.dg/asan/large-func-test-1.C
>>> b/gcc/testsuite/g++.dg/asan/large-func-test-1.C
>>> index 32808e7..0d5c383 100644
>>> --- a/gcc/testsuite/g++.dg/asan/large-func-test-1.C
>>> +++ b/gcc/testsuite/g++.dg/asan/large-func-test-1.C
>>> @@ -37,9 +37,9 @@ int main() {
>>>
>>> // { dg-output "ERROR: AddressSanitizer:? heap-buffer-overflow on
>>> address\[^\n\r]*" }
>>> // { dg-output "0x\[0-9a-f\]+ at pc 0x\[0-9a-f\]+ bp 0x\[0-9a-f\]+ sp
>>> 0x\[0-9a-f\]+\[^\n\r]*(\n|\r\n|\r)" }
>>> -// { dg-output "READ of size 4 at 0x\[0-9a-f\]+ thread
>>> T0\[^\n\r]*(\n|\r\n|\r)" }
>>> +// { dg-output ".*READ of size 4 at 0x\[0-9a-f\]+ thread
>>> T0\[^\n\r]*(\n|\r\n|\r)" }
>>> // { dg-output " #0 0x\[0-9a-f\]+ (in
>>> \[^\n\r]*LargeFunction\[^\n\r]*(large-func-test-1.C:18|\[^\n\r]*:0)|\[(\]).*(\n|\r\n|\r)"
>>> }
>>> -// { dg-output "0x\[0-9a-f\]+ is located 44 bytes to the right of
>>> 400-byte region.*(\n|\r\n|\r)" }
>>> -// { dg-output "allocated by thread T0 here:\[^\n\r]*(\n|\r\n|\r)" }
>>> +// { dg-output ".*0x\[0-9a-f\]+ is located 44 bytes to the right of
>>> 400-byte region.*(\n|\r\n|\r)" }
>>> +// { dg-output ".*allocated by thread T0 here:\[^\n\r]*(\n|\r\n|\r)" }
>>> // { dg-output " #0( 0x\[0-9a-f\]+ (in
>>> _*(interceptor_|)malloc|\[(\])\[^\n\r]*(\n|\r\n|\r)" }
>>> // { dg-output " #1|) 0x\[0-9a-f\]+ (in (operator
>>> new|_*_Zn\[aw\]\[mj\])|\[(\])\[^\n\r]*(\n|\r\n|\r)" }
>>> diff --git a/gcc/testsuite/lib/target-supports.exp
>>> b/gcc/testsuite/lib/target-supports.exp
>>> index 45c8b84..28b6b6d 100644
>>> --- a/gcc/testsuite/lib/target-supports.exp
>>> +++ b/gcc/testsuite/lib/target-supports.exp
>>> @@ -4668,6 +4668,33 @@ proc check_effective_target_simulator { } {
>>> return 0
>>> }
>>>
>>> +# Return 1 if programs are intended to be run on hardware rather than
>>> +# on a simulator
>>> +
>>> +proc check_effective_target_hw { } {
>>> +
>>> + # All "src/sim" simulators set this one.
>>> + if [board_info target exists is_simulator] {
>>> + if [board_info target is_simulator] {
>>> + return 0
>>> + } else {
>>> + return 1
>>> + }
>>> + }
>>> +
>>> + # The "sid" simulators don't set that one, but at least they set
>>> + # this one.
>>> + if [board_info target exists slow_simulator] {
>>> + if [board_info target slow_simulator] {
>>> + return 0
>>> + } else {
>>> + return 1
>>> + }
>>> + }
>>> +
>>> + return 1
>>> +}
>>> +
>>> # Return 1 if the target is a VxWorks kernel.
>>>
>>> proc check_effective_target_vxworks_kernel { } {
>>> diff --git a/libsanitizer/configure.tgt b/libsanitizer/configure.tgt
>>> index 265da01..bdfc22e 100644
>>> --- a/libsanitizer/configure.tgt
>>> +++ b/libsanitizer/configure.tgt
>>> @@ -29,6 +29,8 @@ case "${target}" in
>>> ;;
>>> sparc*-*-linux*)
>>> ;;
>>> + arm*-*-linux*)
>>> + ;;
>>> x86_64-*-darwin[1]* | i?86-*-darwin[1]*)
>>> TSAN_SUPPORTED=no
>>> ;;
>>> diff --git a/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
>>> b/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
>>> index e14ea44..7b3e4ca 100644
>>> --- a/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
>>> +++ b/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
>>> @@ -27,7 +27,7 @@ const char *StripPathPrefix(const char *filepath,
>>> uptr StackTrace::GetPreviousInstructionPc(uptr pc) {
>>> #ifdef __arm__
>>> // Cancel Thumb bit.
>>> - pc = pc & (~1);
>>> + return pc & (~1);
>
> Here you are cancelling "pc - 1" operation, why? It is needed for the
> function to return the address of the _previous_ instruction. It
> matters when the call instruction is the last one in a function
> (because the callee is no-return), and return address is actually
> outside the function.
>
>>> #endif
>>> #if defined(__powerpc__) || defined(__powerpc64__)
>>> // PCs are always 4 byte aligned.
