The majority of this CL was prepared via scripted invocations of
`gofmt -w -r "$SYM -> obj.$SYM" cmd/internal/ld/*.go` and `gofmt -w -r
"ld.$SYM -> obj.$SYM" cmd/?l/*.go`.
Because of issue #7417, that was followed by repeatedly running an AWK
script to identify lines that differed other than whitespace changes
or "ld." or "obj." prefixes and manually restoring comments.
Finally, the redundant constants from cmd/internal/ld/link.go were
removed, and "goimports -w" was used to cleanup import lines.
Passes rsc.io/toolstash/buildall, even when modified to also build cmd.
Fixes#10055.
Change-Id: Icd5dbe819a3b6520ce883748e60017dc8e9a2e85
Reviewed-on: https://go-review.googlesource.com/9112
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
I have left the Diag calls in place where I believe Ctxt.Cursym != nil
which means this CL is not the improvement I had hoped for. However
it is now safe to call Exitf whereever you are in the linker, which
makes it easier to reason about some code.
Change-Id: I8261e761ca9719f7d216e2747314adfe464e3337
Reviewed-on: https://go-review.googlesource.com/8668
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The linker currently (on some platforms) takes a -shared flag, which means
approximately what -buildmode=c-shared means in the in the proposed "Go
Execution Modes" document. As part of implementing other modes, the term
"shared" becomes horribly overloaded, so this replaces -shared with a
-buildmode argument instead (which currently only handles -buildmode=c-shared
and the default -buildmode=exe -- no new behaviour here).
As the linker support for -shared was in 1.4 this retains it as an alias.
Change-Id: Id2ebb8e05ee07f46208a554bc2622d0e67b47082
Reviewed-on: https://go-review.googlesource.com/8304
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
It appears that c2go dropped comments inside struct { ... } and enum { ... }.
Restore them.
Identified missing comments by checking for comments present
in the C code but not the Go code, made a list, and then reapplied
with some mechanical help.
Missing comment finder: http://play.golang.org/p/g6qNUAo1Y0
Change-Id: I323ab45c7ef9d51e28eab3b699eb14bee1eef66b
Reviewed-on: https://go-review.googlesource.com/6899
Reviewed-by: Rob Pike <r@golang.org>
Run rsc.io/grind rev a26569f on C->Go conversions.
The new change in grind is the inlining of goto targets.
If code says 'goto x' and the block starting at label x is unreachable
except through that goto and the code can be moved to where
the goto is without changing the meaning of its variable names,
grind does that move. Simlarly, a goto to a plain return statement
turns into that return statement (even if there are other paths to
the return statement).
Combined, these remove many long-distance gotos, which in turn
makes it possible to reduce the scope of more variable declarations.
(Because gotos can't jump across declarations, the gotos were
keeping the declarations from moving.)
Checked bit-for-bit compatibility with toolstash + buildall.
Reduces compiler runtime in html/template by about 12%.
Change-Id: Id727c0bd7763a61aa22f3daa00aeb8fccbc057a3
Reviewed-on: https://go-review.googlesource.com/6472
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
mv cmd/new5l cmd/5l and so on.
Minimal changes to cmd/dist and cmd/go to keep things building.
More can be deleted in followup CLs.
Change-Id: I1449eca7654ce2580d1f413a56dc4a75f3d4618b
Reviewed-on: https://go-review.googlesource.com/6361
Reviewed-by: Rob Pike <r@golang.org>
Liblink is still needed for the linker (for a bit longer) but mostly not.
Delete the unused parts.
Change-Id: Ie63a7c1520dee52b17425b384943cd16262d36e3
Reviewed-on: https://go-review.googlesource.com/6110
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Make cmd/ld a real library invoked by the individual linkers.
There are no reverse symbol references anymore
(symbols referred to in cmd/ld but defined in cmd/5l etc).
This means that in principle we could do an automatic
conversion of these to Go, as a stopgap until cmd/link is done
or as a replacement for cmd/link.
Change-Id: I4a94570257a3a7acc31601bfe0fad9dea0aea054
Reviewed-on: https://go-review.googlesource.com/4649
Reviewed-by: Rob Pike <r@golang.org>
This isn't everything, but it's a start.
Still producing bit-identical compiler output.
The semantics of the old back ends is preserved,
even when they are probably buggy.
There are some TODOs in gc/gsubr.c to
remove special cases to preserve bugs in 5g and 8g.
Change-Id: I28ae295fbfc94ef9df43e13ab96bd6fc2f194bc4
Reviewed-on: https://go-review.googlesource.com/3802
Reviewed-by: Austin Clements <austin@google.com>
liblink:
- set dummy value for ctxt->tlsoffset.
cmd/ld:
- always do external linking when using cgo on darwin/arm,
as our linker might not generate codesign-compatible binary.
cmd/5l:
- support generate ARM Mach-O binaries
- add machoreloc1() that translate our internal relocation to
macho relocations used by external linking.
Change-Id: Ic5454aeb87009aaf8f1453ec7fe33e6da55d5f06
Reviewed-on: https://go-review.googlesource.com/3273
Reviewed-by: David Crawshaw <crawshaw@golang.org>
This makes names like ANOP, ATEXT, AGLOBL, ACALL, AJMP, ARET
available for use by architecture-independent processing passes.
On arm and ppc64, the alternate names are now aliases for the
official ones (ABL for ACALL, AB or ABR for AJMP, ARETURN for ARET).
Change-Id: Id027771243795af2b3745199c645b6e1bedd7d18
Reviewed-on: https://go-review.googlesource.com/3577
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
Reviewed-by: Austin Clements <austin@google.com>
Use AXXX instead of AGOK (neither is a valid instruction but AXXX is zero)
for the initial setting of Prog.as, and now there are no non-zero default
field settings.
Remove the arch-specific zprog/zprg in favor of a single global zprog.
Remove the arch-specific prg constructor in favor of emallocz(sizeof(Prog)).
Change-Id: Ia73078726768333d7cdba296f548170c1bea9498
Reviewed-on: https://go-review.googlesource.com/3575
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
Reviewed-by: Austin Clements <austin@google.com>
A step toward making the zero Prog useful.
Change-Id: I427b98b1ce9bd8f093da825aa4bb83244fc01903
Reviewed-on: https://go-review.googlesource.com/3573
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Austin Clements <austin@google.com>
Another attempt to fix the arm build by moving the include of signal.h
to cmd/lex.c, unless we are building on plan9.
Obviously if we had a plan9/arm builder this would probably not work, but
this is only a temporary measure until the c2go transition is complete.
Change-Id: I7f8ae27349b2e7a09c55db03e02a01939159a268
Reviewed-on: https://go-review.googlesource.com/3566
Reviewed-by: Russ Cox <rsc@golang.org>
REG_R0 etc are defined in <ucontext.h> on ARM systems.
Possible use of uninitialized n in 8g/reg.c.
Change-Id: I6e8ce83a6515ca2b779ed8a344a25432db629cc2
Reviewed-on: https://go-review.googlesource.com/3578
Reviewed-by: Russ Cox <rsc@golang.org>
Most ppc64 relocations come in six or more variants where the basic
relocation formula is the same, but which bits of the computed value
are installed where changes. Introduce the concept of "variants" for
internal relocations to support this. Since this applies to
architecture-independent relocation types like R_PCREL, we do this in
relocsym.
Currently there is only an identity variant. A later CL that adds
support for ppc64 ELF relocations will introduce more.
Change-Id: I0c5f0e7dbe5beece79cd24fe36267d37c52f1a0c
Reviewed-on: https://go-review.googlesource.com/2005
Reviewed-by: Russ Cox <rsc@golang.org>
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>
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>
The pretty printers for these make it hard to understand
what's actually in the fields of these structures. These
"ugly printers" show exactly what's in each field, which can
be useful for understanding and debugging code.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/175780043
NaCl requires the addition of a 32-byte "halt sled" at the end
of the text segment. This means that segtext.len is actually
32 bytes shorter than reality. The computation of the file offset
of the end of the data segment did not take this 32 bytes into
account, so if len and len+32 rounded up (by 64k) to different
values, the symbol table overwrote the last page of the data
segment.
The last page of the data segment is usually the C .string
symbols, which contain the strings used in error prints
by the runtime. So when this happens, your program
probably crashes, and then when it does, you get binary
garbage instead of all the usual prints.
The chance of hitting this with a randomly sized text segment
is 32 in 65536, or 1 in 2048.
If you add or remove ANY code while trying to debug this
problem, you're overwhelmingly likely to bump the text
segment one way or the other and make the bug disappear.
Correct all the computations to use segdata.fileoff+segdata.filelen
instead of trying to rederive segdata.fileoff.
This fixes the failure during the nacl/amd64p32 build.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/135050043
The helps certain diagnostics and also removed duplicated enums as a side effect.
LGTM=dave, rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/115060044
The main changes fall into a few patterns:
1. Replace #define with enum.
2. Add /*c2go */ comment giving effect of #define.
This is necessary for function-like #defines and
non-enum-able #defined constants.
(Not all compilers handle negative or large enums.)
3. Add extra braces in struct initializer.
(c2go does not implement the full rules.)
This is enough to let c2go typecheck the source tree.
There may be more changes once it is doing
other semantic analyses.
LGTM=minux, iant
R=minux, dave, iant
CC=golang-codereviews
https://golang.org/cl/106860045
The new code is adapted from the Go 1.2 nosplit code,
but it does not have the bug reported in issue 7623:
g% go run nosplit.go
g% go1.2 run nosplit.go
BUG
rejected incorrectly:
main 0 call f; f 120
linker output:
# _/tmp/go-test-nosplit021064539
main.main: nosplit stack overflow
120 guaranteed after split check in main.main
112 on entry to main.f
-8 after main.f uses 120
g%
Fixes#6931.
Fixes#7623.
LGTM=iant
R=golang-codereviews, iant, ality
CC=golang-codereviews, r
https://golang.org/cl/88190043
The relocation and automatic variable types were using
arch-specific numbers. Introduce portable enumerations
instead.
To the best of my knowledge, these are the only arch-specific
bits left in the new object file format.
Remove now, before Go 1.3, because file formats are forever.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/87670044
The new channel and map runtime routines take pointers
to values, typically temporaries. Without help, the compiler
cannot tell when those temporaries stop being needed,
because it isn't sure what happened to the pointer.
Arrange to insert explicit VARKILL instructions for these
temporaries so that the liveness analysis can avoid seeing
them as "ambiguously live".
The change is made in order.c, which was already in charge of
introducing temporaries to preserve the order-of-evaluation
guarantees. Now its job has expanded to include introducing
temporaries as needed by runtime routines, and then also
inserting the VARKILL annotations for all these temporaries,
so that their lifetimes can be shortened.
In order to do its job for the map runtime routines, order.c arranges
that all map lookups or map assignments have the form:
x = m[k]
x, y = m[k]
m[k] = x
where x, y, and k are simple variables (often temporaries).
Likewise, receiving from a channel is now always:
x = <-c
In order to provide the map guarantee, order.c is responsible for
rewriting x op= y into x = x op y, so that m[k] += z becomes
t = m[k]
t2 = t + z
m[k] = t2
While here, fix a few bugs in order.c's traversal: it was failing to
walk into select and switch case bodies, so order of evaluation
guarantees were not preserved in those situations.
Added tests to test/reorder2.go.
Fixes#7671.
In gc/popt's temporary-merging optimization, allow merging
of temporaries with their address taken as long as the liveness
ranges do not intersect. (There is a good chance of that now
that we have VARKILL annotations to limit the liveness range.)
Explicitly killing temporaries cuts the number of ambiguously
live temporaries that must be zeroed in the godoc binary from
860 to 711, or -17%. There is more work to be done, but this
is a good checkpoint.
Update #7345
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/81940043
This CL replays the following one CL from the rsc-go13nacl repo.
This is the last replay CL: after this CL the main repo will have
everything the rsc-go13nacl repo did. Changes made to the main
repo after the rsc-go13nacl repo branched off probably mean that
NaCl doesn't actually work after this CL, but all the code is now moved
over and just needs to be redebugged.
---
cmd/6l, cmd/8l, cmd/ld: support for Native Client
See golang.org/s/go13nacl for design overview.
This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.
This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.
R≡khr
https://golang.org/cl/15750044
---
LGTM=bradfitz, dave, iant
R=dave, bradfitz, iant
CC=golang-codereviews
https://golang.org/cl/69040044
The "fat" referred to being used for multiword values only.
We're going to use it for non-fat values sometimes too.
No change other than the renaming.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/63650043
We now use the %A, %D, %P, and %R routines from liblink
across the board.
Fixes#7178.
Fixes#7055.
LGTM=iant
R=golang-codereviews, gobot, rsc, dave, iant, remyoudompheng
CC=golang-codereviews
https://golang.org/cl/49170043
rsc suggested that we split the whole linker changes into three parts.
This is the first one, mostly dealing with adding Hsolaris.
LGTM=iant
R=golang-codereviews, iant, dave
CC=golang-codereviews
https://golang.org/cl/54210050
CL 56120043 fixed and cleaned up TLS on ARM after introducing liblink, but
left flag_shared broken. This CL restores the (unsupported) flag_shared
behaviour by simply rewriting access to $runtime.tlsgm(SB) with
runtime.tlsgm(SB), to compensate for the extra indirection when going from
the R_ARM_TLS_LE32 relocation to the R_ARM_TLS_IE32 relocation.
Also, remove unnecessary symbol lookup left after 56120043.
LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/57000043
CL 56120043 fixed TLS handling on ARM after the introduction of
liblink but left older ARM processors broken.
Before liblink, the MRC instruction was replaced with a fallback
on older ARMs. CL 56120043 removed that, because the rewrite matched
bit patterns on the AWORD pseudo-instruction and could therefore change
unrelated AWORDs that happened to match.
This CL adds an AMRC instruction to encode both MRC and MCR previously
encoded as AWORDs. Then, in liblink, the AMRC instructions are either
rewritten to AWORD, or, on goarm < 7, replaced with a branch to the
fallback.
./all.bash completes successfully on an ARMv7 with either GOARM=7 or
GOARM=5. I have verified that the fallback is indeed present in both
runtime.save_gm and runtime.load_gm when GOARM=5 but not when GOARM=7.
If all goes well, this should fix the armv5 builders.
LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/55540044
- 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
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
This change allows the garbage collector to examine stack
slots that are determined as live and containing a pointer
value by the garbage collector. This results in a mean
reduction of 65% in the number of stack slots scanned during
an invocation of "GOGC=1 all.bash".
Unfortunately, this does not yet allow garbage collection to
be precise for the stack slots computed as live. Pointers
confound the determination of what definitions reach a given
instruction. In general, this problem is not solvable without
runtime cost but some advanced cooperation from the compiler
might mitigate common cases.
R=golang-dev, rsc, cshapiro
CC=golang-dev
https://golang.org/cl/14430048
Two bugs:
1. The first iteration of the traceback always uses LR when provided,
which it is (only) during a profiling signal, but in fact LR is correct
only if the stack frame has not been allocated yet. Otherwise an
intervening call may have changed LR, and the saved copy in the stack
frame should be used. Fix in traceback_arm.c.
2. The division runtime call adds 8 bytes to the stack. In order to
keep the traceback routines happy, it must copy the saved LR into
the new 0(SP). Change
SUB $8, SP
into
MOVW 0(SP), R11 // r11 is temporary, for use by linker
MOVW.W R11, -8(SP)
to update SP and 0(SP) atomically, so that the traceback always
sees a saved LR at 0(SP).
Fixes#6681.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/19910044
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes#6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes#6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
