cmd/ld: add a text generation pass

This will be used by ppc64 to add call stubs to the .text section.
ARM needs a similar pass to generate veneers for arm->thumb
transitions.

Change-Id: Iaee74036e60643a56fab15b564718f359c5910eb
Reviewed-on: https://go-review.googlesource.com/2004
Reviewed-by: Russ Cox <rsc@golang.org>
cmd/5l,6l,8l: remove bogus dynsym section indexes

Previously, this code generated bogus section indexes for dynamic
symbols.  It turns out this didn't matter, since we only emit these
when generating an executable and in an executable it only matters
whether a symbol is defined or undefined, but it leads to perplexing
code full of mysterious constants.

Unfortunately, this happens too early to put in real section indexes,
so just use section index 1 to distinguish the symbol from an
undefined symbol.

Change-Id: I0e514604bf31f21683598ebd3e020b66acf767ef
Reviewed-on: https://go-review.googlesource.com/1720
Reviewed-by: Russ Cox <rsc@golang.org>
test: add test case that gccgo failed to link

Gccgo creates a struct to hold the arguments for the deferred
function.  In this example the struct holds a type defined in a
different package.  The bug was that gccgo tried to create an equality
function for this struct, and it implemented that function by calling
the equality function for the type defined in the other package.
Since that type is not exported, the reference to the equality
function failed at link time.  Normally it is impossible for a struct
to directly contain a member that is an unexported type from another
package, but in this specific case it was possible.  Fixed in gccgo
with https://codereview.appspot.com/183500043 .

Change-Id: I8ec3a33631225b9ac2a4ac060cb4d10b4635e60b
Reviewed-on: https://go-review.googlesource.com/1690
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
runtime: fix nacl build, hashmap overflow field offset was incorrect.

Change-Id: Ieb305b2a4d4ef28d70a8b8ece703f495c5af0529
Reviewed-on: https://go-review.googlesource.com/2051
Reviewed-by: Keith Randall <khr@golang.org>
syscall: fix the deprecated way of parsing routing message on openbsd

OpenBSD 5.5 changed its kernel ABI and OpenBSD 5.6 enabled it.
This CL works on both 5.5 and 5.6.

Fixes #9102.

Change-Id: I4a295be9ab8acbc99e550d8cb7e8f8dacf3a03c5
Reviewed-on: https://go-review.googlesource.com/1932
Reviewed-by: Ian Lance Taylor <iant@golang.org>
cmd/9l: improve R_CALLPOWER error messages

Change-Id: I8670540a2a9647efbd8b072a54272a04c530e54b
Reviewed-on: https://go-review.googlesource.com/2001
Reviewed-by: Minux Ma <minux@golang.org>
runtime: make stack frames fixed size by modifying goproc/deferproc.

Calls to goproc/deferproc used to push & pop two extra arguments,
the argument size and the function to call.  Now, we allocate space
for those arguments in the outargs section so we don't have to
modify the SP.

Defers now use the stack pointer (instead of the argument pointer)
to identify which frame they are associated with.

A followon CL might simplify funcspdelta and some of the stack
walking code.

Fixes issue #8641

Change-Id: I835ec2f42f0392c5dec7cb0fe6bba6f2aed1dad8
Reviewed-on: https://go-review.googlesource.com/1601
Reviewed-by: Russ Cox <rsc@golang.org>
test: fix windows build

Broken by e7173dfdfd1c74b1d301da9b6f295ef99b9cc11c

Fix by simply disabling the relevant tests.

* bug248 and bug345 require errchk, but we can't
  rely on perl being available.
* bug369 is disabled anyway.

Change-Id: Idf73ebccb066943e3fe17c2f662b37238ec74dfe
Reviewed-on: https://go-review.googlesource.com/2052
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
cmd/6g, cmd/8g, liblink: improve handling of float constants

* Do constant propagation for floats.
* Implement MOVSS $(0), Xx and MOVSD $(0), Xx as XORPS Xx, Xx.

Change-Id: Ie9eb65e324af4f664153d0a7cd22bb16b0fba16d