This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.
Go policy has been single space after periods in comments for some time.
The copyright header template at:
https://golang.org/doc/contribute.html#copyright
also uses a single space.
Make them all consistent.
Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The PowerPC ISA does not have a PC-relative load instruction, which poses
obvious challenges when generating position-independent code. The way the ELFv2
ABI addresses this is to specify that r2 points to a per "module" (shared
library or executable) TOC pointer. Maintaining this pointer requires
cooperation between codegen and the system linker:
* Non-leaf functions leave space on the stack at r1+24 to save the TOC pointer.
* A call to a function that *might* have to go via a PLT stub must be followed
by a nop instruction that the system linker can replace with "ld r1, 24(r1)"
to restore the TOC pointer (only when dynamically linking Go code).
* When calling a function via a function pointer, the address of the function
must be in r12, and the first couple of instructions (the "global entry
point") of the called function use this to derive the address of the TOC
for the module it is in.
* When calling a function that is implemented in the same module, the system
linker adjusts the call to skip over the instructions mentioned above (the
"local entry point"), assuming that r2 is already correctly set.
So this changeset adds the global entry point instructions, sets the metadata so
the system linker knows where the local entry point is, inserts code to save the
TOC pointer at 24(r1), adds a nop after any call not known to be local and copes
with the odd non-local code transfer in the runtime (e.g. the stuff around
jmpdefer). It does not actually compile PIC yet.
Change-Id: I7522e22bdfd2f891745a900c60254fe9e372c854
Reviewed-on: https://go-review.googlesource.com/15967
Reviewed-by: Russ Cox <rsc@golang.org>
PIC code on ppc64le uses R2 as a TOC pointer and when calling a function
through a function pointer must ensure the function pointer is in R12. These
rules are easy enough to follow unconditionally in our assembly, so do that.
Change-Id: Icfc4e47ae5dfbe15f581cbdd785cdeed6e40bc32
Reviewed-on: https://go-review.googlesource.com/15526
Reviewed-by: Ian Lance Taylor <iant@golang.org>
I cannot find where it's being used.
This addresses a duplicate symbol issue encountered in golang/go#9327.
Change-Id: I8efda45a006ad3e19423748210c78bd5831215e0
Reviewed-on: https://go-review.googlesource.com/13615
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This implements support for calls to and from C in the ppc64 C ABI, as
well as supporting functionality such as an entry point from the
dynamic linker.
Change-Id: I68da6df50d5638cb1a3d3fef773fb412d7bf631a
Reviewed-on: https://go-review.googlesource.com/2009
Reviewed-by: Russ Cox <rsc@golang.org>
