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| author | Evan Cheng <evan.cheng@apple.com> | 2012-02-28 06:42:03 +0000 |
|---|---|---|
| committer | Evan Cheng <evan.cheng@apple.com> | 2012-02-28 06:42:03 +0000 |
| commit | ec52aaa12f57896fc806e849fa21a61603050ac4 (patch) | |
| tree | 6c4c80ccf055e5a0cf0ab3a4a63e70868a5ba059 /lib/Target/Mips/MipsMCInstLower.h | |
| parent | 1f5952352146f229cbc249405fbe9898d168089b (diff) | |
| download | llvm-ec52aaa12f57896fc806e849fa21a61603050ac4.tar.gz llvm-ec52aaa12f57896fc806e849fa21a61603050ac4.tar.bz2 llvm-ec52aaa12f57896fc806e849fa21a61603050ac4.tar.xz | |
Some ARM implementaions, e.g. A-series, does return stack prediction. That is,
the processor keeps a return addresses stack (RAS) which stores the address
and the instruction execution state of the instruction after a function-call
type branch instruction.
Calling a "noreturn" function with normal call instructions (e.g. bl) can
corrupt RAS and causes 100% return misprediction so LLVM should use a
unconditional branch instead. i.e.
mov lr, pc
b _foo
The "mov lr, pc" is issued in order to get proper backtrace.
rdar://8979299
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151623 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/Mips/MipsMCInstLower.h')
0 files changed, 0 insertions, 0 deletions