delta/go-git.git/src/cmd/internal/obj/mips, branch dev.link

cmd/internal/obj: move LSym.Func into LSym.Extra

2020-10-16T03:02:36+00:00

This creates space for a different kind of extension field
in LSym without making the struct any larger.
(There are many LSym, so we care about keeping the struct small.)

Change-Id: Ib16edb9e15f54c2a7351c8b875e19684058711e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/243943
Trust: Russ Cox 
Run-TryBot: Russ Cox 
TryBot-Result: Go Bot 
Reviewed-by: Cherry Zhang

cmd/compile,cmd/asm: simplify recording of branch targets, take 2

2020-08-31T17:36:08+00:00

We currently use two fields to store the targets of branches.
Some phases use p.To.Val, some use p.Pcond. Rewrite so that
every branch instruction uses p.To.Val.
p.From.Val is also used in rare instances.
Introduce a Pool link for use by arm/arm64, instead of
repurposing Pcond.

This is a cleanup CL in preparation for some stack frame CLs.

Change-Id: If8239177e4b1ea2bccd0608eb39553d23210d405
Reviewed-on: https://go-review.googlesource.com/c/go/+/251437
Run-TryBot: Keith Randall 
TryBot-Result: Gobot Gobot 
Reviewed-by: Cherry Zhang

Revert "cmd/compile,cmd/asm: simplify recording of branch targets"

2020-08-28T02:10:13+00:00

This reverts CL 243318.

Reason for revert: Seems to be crashing some builders.

Change-Id: I2ffc59bc5535be60b884b281c8d0eff4647dc756
Reviewed-on: https://go-review.googlesource.com/c/go/+/251169
Reviewed-by: Bryan C. Mills

cmd/compile,cmd/asm: simplify recording of branch targets

2020-08-27T22:35:45+00:00

We currently use two fields to store the targets of branches.
Some phases use p.To.Val, some use p.Pcond. Rewrite so that
every branch instruction uses p.To.Val.
p.From.Val is also used in rare instances.
Introduce a Pool link for use by arm/arm64, instead of
repurposing Pcond.

This is a cleanup CL in preparation for some stack frame CLs.

Change-Id: I9055bf0a1d986aff421e47951a1dedc301c846f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/243318
Run-TryBot: Keith Randall 
TryBot-Result: Gobot Gobot 
Reviewed-by: Cherry Zhang

cmd/internal/obj: stop removing NOPs from instruction stream

2020-08-20T01:12:34+00:00

This has already been done for s390x, ppc64. This CL is for
all the other architectures.

Fixes #40796

Change-Id: Idd1816e057df63022d47e99fa06617811d8c8489
Reviewed-on: https://go-review.googlesource.com/c/go/+/248684
Run-TryBot: Cherry Zhang 
TryBot-Result: Gobot Gobot 
Reviewed-by: Cherry Zhang

cmd/internal/obj/mips: mark restartable sequences

2020-05-06T15:41:25+00:00

Following CL 208126, do the same for MIPS.

Change-Id: I95f8fc99a234524119a4d29c7695676dc0ea1025
Reviewed-on: https://go-review.googlesource.com/c/go/+/208217
Run-TryBot: Cherry Zhang 
TryBot-Result: Gobot Gobot 
Reviewed-by: Austin Clements

cmd/internal/obj, runtime: preempt & restart some instruction sequences

2020-05-06T15:41:12+00:00

On some architectures, for async preemption the injected call
needs to clobber a register (usually REGTMP) in order to return
to the preempted function. As a consequence, the PC ranges where
REGTMP is live are not preemptible.

The uses of REGTMP are usually generated by the assembler, where
it needs to load or materialize a large constant or offset that
doesn't fit into the instruction. In those cases, REGTMP is not
live at the start of the instruction sequence. Instead of giving
up preemption in those cases, we could preempt it and restart the
sequence when resuming the execution. Basically, this is like
reissuing an interrupted instruction, except that here the
"instruction" is a Prog that consists of multiple machine
instructions. For this to work, we need to generate PC data to
mark the start of the Prog.

Currently this is only done for ARM64.

TODO: the split-stack function prologue is currently not async
preemptible. We could use this mechanism, preempt it and restart
at the function entry.

Change-Id: I37cb282f8e606e7ab6f67b3edfdc6063097b4bd1
Reviewed-on: https://go-review.googlesource.com/c/go/+/208126
Run-TryBot: Cherry Zhang 
TryBot-Result: Gobot Gobot 
Reviewed-by: Austin Clements

cmd/internal/obj/mips: don't emit spurious CALLIND relocations

2020-04-03T13:43:12+00:00

Generate a CALLIND relocation only for indirect calls, not for
indirect jumps. In particular, the RET instruction is lowered to
JMP (LR), an indirect jump, and occurs frequently. The large
amount of spurious relocations causes the linker to do a lot of
extra work.

Change-Id: Ie0edc04609788f5a687fd00c22558c3f83867697
Reviewed-on: https://go-review.googlesource.com/c/go/+/227079
Run-TryBot: Cherry Zhang 
TryBot-Result: Gobot Gobot 
Reviewed-by: Than McIntosh 
Reviewed-by: David Chase

cmd/asm, cmd/compile, runtime: add -spectre=ret mode

2020-03-13T19:05:54+00:00

This commit extends the -spectre flag to cmd/asm and adds
a new Spectre mitigation mode "ret", which enables the use
of retpolines.

Retpolines prevent speculation about the target of an indirect
jump or call and are described in more detail here:
https://support.google.com/faqs/answer/7625886

Change-Id: I4f2cb982fa94e44d91e49bd98974fd125619c93a
Reviewed-on: https://go-review.googlesource.com/c/go/+/222661
Reviewed-by: Keith Randall

cmd/asm: add MIPS MSA LD/ST/LDI support for mips64x

2020-03-04T19:06:44+00:00

This CL adding primitive asm support of MIPS MSA by introducing
new sets of register W0-W31 (C_WREG) and 12 new instructions:

* VMOV{B,H,W,D} ADDCONST, WREG  (Vector load immediate)
* VMOV{B,H,W,D} SOREG, WREG     (Vector load)
* VMOV{B,H,W,D} WREG, SOREG     (Vector store)

Ref: MIPS Architecture for Programmers Volume IV-j: The MIPS64 SIMD Architecture Module

Change-Id: I3362c59a73c82c94769c18a19a0bee7e5029217d
Reviewed-on: https://go-review.googlesource.com/c/go/+/215723
Run-TryBot: Meng Zhuo 
TryBot-Result: Gobot Gobot 
Reviewed-by: Cherry Zhang