This patch series improves change-of-flow handling.
Currently, we set the PC to a new address before exiting a TB. The
ultimate goal is to use direct block chaining. However, several steps
are needed along the way.
1)
When a packet has more than one change-of-flow (COF) instruction, only
the first one taken is considered. The runtime bookkeeping is only
needed when there is more than one COF instruction in a packet.
2, 3)
Remove PC and next_PC from the runtime state and always use a
translation-time constant. Note that next_PC is used by call instructions
to set LR and by conditional COF instructions to set the fall-through
address.
4, 5, 6)
Add helper overrides for COF instructions. In particular, we must
distinguish those that use a PC-relative address for the destination.
These are candidates for direct block chaining later.
7)
Use direct block chaining for packets that have a single PC-relative
COF instruction. Instead of generating the code while processing the
instruction, we record the effect in DisasContext and generate the code
during gen_end_tb.
8)
Use direct block chaining for tight loops. We look for TBs that end
with an endloop0 that will branch back to the TB start address.
**** Changes in V2 ****
Simplify test in need_pkt_has_multi_cof
Address feedback from Matheus Tavares Bernardino <quic_mathb...@quicinc.com>
Rearrange new-value-jump overrides
Simplify gen_write_new_pc_addr
Taylor Simpson (8):
Hexagon (target/hexagon) Only use branch_taken when packet has multi
cof
Hexagon (target/hexagon) Remove PC from the runtime state
Hexagon (target/hexagon) Remove next_PC from runtime state
Hexagon (target/hexagon) Add overrides for direct call instructions
Hexagon (target/hexagon) Add overrides for compound compare and jump
Hexagon (target/hexagon) Add overrides for various forms of jump
Hexagon (target/hexagon) Use direct block chaining for direct
jump/branch
Hexagon (target/hexagon) Use direct block chaining for tight loops
target/hexagon/cpu.h | 18 +-
target/hexagon/gen_tcg.h | 390 ++++++++++++++++++++++++++++
target/hexagon/insn.h | 2 +
target/hexagon/macros.h | 6 +-
target/hexagon/translate.h | 6 +-
target/hexagon/decode.c | 15 +-
target/hexagon/genptr.c | 260 +++++++++++++++++++
target/hexagon/op_helper.c | 28 +-
target/hexagon/translate.c | 120 +++++++--
target/hexagon/gen_helper_funcs.py | 11 +
target/hexagon/gen_helper_protos.py | 12 +-
target/hexagon/gen_tcg_funcs.py | 11 +
target/hexagon/hex_common.py | 29 ++-
13 files changed, 863 insertions(+), 45 deletions(-)
--
2.17.1
