Commit Graph

4 Commits

Author SHA1 Message Date
Russ Cox 9b976f5f03 cmd/gc: record line number for auto-generated wrappers as <autogenerated>:1
Before we used line 1 of the first source file.
This should be clearer.

Fixes #4388.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/92250044
2014-05-12 11:59:55 -04:00
Russ Cox e97b3ab1f9 build: remove tmp dir names from objects, support GOROOT_FINAL again
If we compile a generated file stored in a temporary
directory - let's say /tmp/12345/work/x.c - then by default
6c stores the full path and then the pcln table in the
final binary includes the full path. This makes repeated builds
(using different temporary directories) produce different
binaries, even if the inputs are the same.

In the old 'go tool pack', the P flag specified a prefix to remove
from all stored paths (if present), and cmd/go invoked
'go tool pack grcP $WORK' to remove references to the
temporary work directory.

We've changed the build to avoid pack as much as possible,
under the theory that instead of making pack convert from
.6 to .a, the tools should just write the .a directly and save a
round of I/O.

Instead of going back to invoking pack always, define a common
flag -trimpath in the assemblers, C compilers, and Go compilers,
implemented in liblink, and arrange for cmd/go to use the flag.
Then the object files being written out have the shortened paths
from the start.

While we are here, reimplement pcln support for GOROOT_FINAL.
A build in /tmp/go uses GOROOT=/tmp/go, but if GOROOT_FINAL=/usr/local/go
is set, then a source file named /tmp/go/x.go is recorded instead as
/usr/local/go/x.go. We use this so that we can prepare distributions
to be installed in /usr/local/go without actually working in that
directory. The conversion to liblink deleted all the old file name
handling code, including the GOROOT_FINAL translation.
Bring the GOROOT_FINAL translation back.

Before this CL, using GOROOT_FINAL=/goroot make.bash:

        g% strings $(which go) | grep -c $TMPDIR
        6
        g% strings $(which go) | grep -c $GOROOT
        793
        g%

After this CL:

        g% strings $(which go) | grep -c $TMPDIR
        0
        g% strings $(which go) | grep -c $GOROOT
        0
        g%

(The references to $TMPDIR tend to be cgo-generated source files.)

Adding the -trimpath flag to the assemblers required converting
them to the new Go-semantics flag parser. The text in go1.3.html
is copied and adjusted from go1.1.html, which is when we applied
that conversion to the compilers and linkers.

Fixes #6989.

LGTM=iant
R=r, iant
CC=golang-codereviews
https://golang.org/cl/88300045
2014-04-15 20:46:46 -04:00
Russ Cox a9f6db58ce cmd/ld: move instruction selection + layout into compilers, assemblers
- new object file reader/writer (liblink/objfile.c)
- remove old object file writing routines
- add pcdata iterator
- remove all trace of "line number stack" and "path fragments" from
  object files, linker (!!!)
- dwarf now writes a single "compilation unit" instead of one per package

This CL disables the check for chains of no-split functions that
could overflow the stack red zone. A future CL will attack the problem
of reenabling that check (issue 6931).

This CL is just the liblink and cmd/ld changes.
There are minor associated adjustments in CL 37030045.
Each depends on the other.

R=golang-dev, dave, iant
CC=golang-dev
https://golang.org/cl/39680043
2013-12-16 12:51:58 -05:00
Russ Cox 7d507dc6e6 liblink: create new library based on linker code
There is an enormous amount of code moving around in this CL,
but the code is the same, and it is invoked in the same ways.
This CL is preparation for the new linker structure, not the new
structure itself.

The new library's definition is in include/link.h.

The main change is the use of a Link structure to hold all the
linker-relevant state, replacing the smattering of global variables.
The Link structure should both make it clearer which state must
be carried around and make it possible to parallelize more easily
later.

The main body of the linker has moved into the architecture-independent
cmd/ld directory. That includes the list of known header types, so the
distinction between Hplan9x32 and Hplan9x64 is removed (no other
header type distinguished 32- and 64-bit formats), and code for unused
formats such as ipaq kernels has been deleted.

The code being deleted from 5l, 6l, and 8l reappears in liblink or in ld.
Because multiple files are being merged in the liblink directory,
it is not possible to show the diffs nicely in hg.

The Prog and Addr structures have been unified into an
architecture-independent form and moved to link.h, where they will
be shared by all tools: the assemblers, the compilers, and the linkers.
The unification makes it possible to write architecture-independent
traversal of Prog lists, among other benefits.

The Sym structures cannot be unified: they are too fundamentally
different between the linker and the compilers. Instead, liblink defines
an LSym - a linker Sym - to be used in the Prog and Addr structures,
and the linker now refers exclusively to LSyms. The compilers will
keep using their own syms but will fill out the corresponding LSyms in
the Prog and Addr structures.

Although code from 5l, 6l, and 8l is now in a single library, the
code has been arranged so that only one architecture needs to
be linked into a particular program: 5l will not contain the code
needed for x86 instruction layout, for example.

The object file writing code in liblink/obj.c is from cmd/gc/obj.c.

Preparation for golang.org/s/go13linker work.

This CL does not build by itself. It depends on 35740044
and will be submitted at the same time.

R=iant
CC=golang-dev
https://golang.org/cl/35790044
2013-12-08 22:49:37 -05:00