cmd/asm,cmd/compile,cmd/link,cmd/objdump: ppc64 ISA 3.1 support #44549
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cagedmantis
added
NeedsInvestigation
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There is work being done to provide support in the assembler and disassembler on ppc64x for some instructions in ISA 3.1. The Go compiler will not be generating any of these instructions yet but they can be assembled and verified that they assemble to the correct instruction bits. Based on the recent comment in golang-dev about the Go 1.17 freeze, should this be marked as part of the Go 1.17 milestone? |
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I would like to get the cmd/objdump support in for 1.17. It would be nice to get support for aligning prefixed opcodes in cmd/asm, but that is not a release blocker. |
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A bit OT: Does/Can the Go compiler generate instructions for float128 FPU calculations on this architecture? I wonder because there is no float128 type. One of the big advantages of this architecture is the native float128 support. |
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Change https://golang.org/cl/347050 mentions this issue: |
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Change https://golang.org/cl/350152 mentions this issue: |
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Change https://golang.org/cl/352791 mentions this issue: |
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Change https://golang.org/cl/355149 mentions this issue: |
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Change https://golang.org/cl/355150 mentions this issue: |
Insert machine NOPs when a prefixed instruction crosses a 64B boundary. ISA 3.1 prohibits prefixed instructions being placed across them. Such instructions generate SIGILL if executed. Likewise, adjust the function alignment to guarantee such instructions can never cross one. And, don't pad the PC based on alignment. The linker can fit these more optimally. Likewise, include the function alignment when printing function debug information. This is needed to verify function alignment happens. Updates #44549 Change-Id: I434fb0ee4e984ca00dc4566f7569c3bcdf93f910 Reviewed-on: https://go-review.googlesource.com/c/go/+/347050 Run-TryBot: Paul Murphy <murp@ibm.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
This introduces a number of new classifications which will make it easier to generate functions to assemble the new instructions of ISA 3.1, and potentially earlier versions. No code generation changes should occur as a result of these. These allow finer control over how an opcode is matched to an optab entry. Literal values are now classified based on the smallest number of bits needed to encode, and matching rules will accept a literal if it can be zero/sign extended to fit a larger literal class. Likewise, support classifying even register numbers for GPR, VSX, and FPR instructions. Some instructions require and even/odd register pair, and these are usually represented by specifying the even register, and similarly encoded. Likewise, add a unit test for the argument classifier function (aclass). This caught an off-by-one bug in aclass which is also fixed. Updates #44549 Change-Id: Ia03013aea8b56c4d59b7c3812cdd67ddb3b720b9 Reviewed-on: https://go-review.googlesource.com/c/go/+/350152 Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com> Run-TryBot: Cherry Mui <cherryyz@google.com> TryBot-Result: Go Bot <gobot@golang.org>
This is a container task for implementing support for the upcoming POWER10 processor.
ISA 3.1 documentation can be found here.
Notable additions we would like to support in golang:
The latter two features will require a bit of preparation work in the ppc64 backend. Go 1.17 development will focus on preparation work.
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