The current implementation does not support calling C variadic
functions (as discussed in #975). Document that.
Fixes#23537
Change-Id: If4c684a3d135f3c2782a720374dc4c07ea66dcbb
Reviewed-on: https://go-review.googlesource.com/90415
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When using the special import "C", the "cgo" build constraint is implied for the go file,
potentially triggering unclear "undefined" error messages.
Explicitly explain this in the documentation.
Updates #24068
Change-Id: Ib656ceccd52c749ffe7fb2d3db9ac144f17abb32
GitHub-Last-Rev: 5a13f00a9b
GitHub-Pull-Request: golang/go#24072
Reviewed-on: https://go-review.googlesource.com/96655
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Both gcc and clang accept an option -fplugin=code.so to load
a plugin from the ELF shared object file code.so.
Obviously that plugin can then do anything it wants
during the build. This is contrary to the goal of "go get"
never running untrusted code during the build.
(What happens if you choose to run the result of
the build is your responsibility.)
Disallow this behavior by only allowing a small set of
known command-line flags in #cgo CFLAGS directives
(and #cgo LDFLAGS, etc).
The new restrictions can be adjusted by the environment
variables CGO_CFLAGS_ALLOW, CGO_CFLAGS_DISALLOW,
and so on. See the documentation.
In addition to excluding cgo-defined flags, we also have to
make sure that when we pass file names on the command
line, they don't look like flags. So we now refuse to build
packages containing suspicious file names like -x.go.
A wrinkle in all this is that GNU binutils uniformly accept
@foo on the command line to mean "if the file foo exists,
then substitute its contents for @foo in the command line".
So we must also reject @x.go, flags and flag arguments
beginning with @, and so on.
Fixes#23672, CVE-2018-6574.
Change-Id: I59e7c1355155c335a5c5ae0d2cf8fa7aa313940a
Reviewed-on: https://team-review.git.corp.google.com/209949
Reviewed-by: Ian Lance Taylor <iant@google.com>
Cgo currently maps CFTypeRef and its subtypes to unsafe.Pointer
or a pointer to a named empty struct.
However, Darwin sometimes encodes some of CFTypeRef's subtypes as a
few int fields packed in a pointer wrapper. This hackery confuses the
Go runtime as the pointers can look like they point to things that
shouldn't be pointed at.
Switch CFTypeRef and its subtypes to map to uintptr.
Detecting the affected set of types is tricky, there are over 200 of
them, and the set isn't static across Darwin versions. Fortunately,
downcasting from CFTypeRef to a subtype requires calling CFGetTypeID,
getting a CFTypeID token, and comparing that with a known id from a
*GetTypeID() call. So we can find all the type names by detecting all
the *GetTypeID() prototypes and rewriting the corresponding *Ref types
to uintptr. This strategy covers all the cases I've checked and is
unlikely to have a false positive.
Update #23091.
Change-Id: I487eb4105c9b4785ba564de9c38d472c8c9a76ac
Reviewed-on: https://go-review.googlesource.com/87615
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Some C types are declared as pointers, but C code
stores non-pointers in them. When the Go garbage
collector sees such a pointer, it gets unhappy.
Instead, for these types represent them on the Go
side with uintptr.
We need this change to handle Apple's CoreFoundation
CF*Ref types. Users of these types might need to
update their code like we do in root_cgo_darwin.go.
The only change that is required under normal
circumstances is converting some nils to 0.
A go fix module is provided to help.
Fixes#21897
RELNOTE=yes
Change-Id: I9716cfb255dc918792625f42952aa171cd31ec1b
Reviewed-on: https://go-review.googlesource.com/66332
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Permit the C preamble to use the _GoString_ type. Permit Go code to
pass string values directly to those C types. Add accessors for C
code to retrieve sizes and pointers.
Fixes#6907
Change-Id: I190c88319ec88a3ef0ddb99f342a843ba69fcaa3
Reviewed-on: https://go-review.googlesource.com/70890
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Even though cmd/dist has historically distinguished "CC for gohostos/gohostarch"
from "CC for target goos/goarch", it has not recorded that distinction
for later use by cmd/cgo and cmd/go. Now that content-based staleness
includes the CC setting in the decision about when to rebuild packages,
the go command needs to know the details of which CC to use when.
Otherwise lots of things look out of date and (worse) may be rebuilt with
the wrong CC.
A related issue is that users may want to be able to build a toolchain
capable of cross-compiling for two different non-host targets, and
to date we've required that CC_FOR_TARGET apply to both.
This CL introduces CC_FOR_${GOOS}_${GOARCH}, so that you can
(for example) set CC_FOR_linux_arm and CC_FOR_linux_arm64
separately on a linux/ppc64 host and be able to cross-compile to
either arm or arm64 with the right toolchain.
Fixes#8161.
Half of a fix for #22509.
Change-Id: I7a43769f39d859f659d31bc96980918ba102fb83
Reviewed-on: https://go-review.googlesource.com/76018
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Also add -V=full to print a unique identifier of the specific tool being invoked.
This will be used for content-based staleness.
Also sort and clean up a few of the flag doc comments.
Change-Id: I786fe50be0b8e5f77af809d8d2dab721185c2abd
Reviewed-on: https://go-review.googlesource.com/68590
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The approach of https://golang.org/cl/43476 turned out incorrect.
The problem is that the sniff introduced by the CL only work for simple
expression. And when it fails it fallback to uint64, not int64, which
breaks backward compatibility.
In this CL, we use DWARF for guessing kind instead. That should be more
reliable than previous approach. And importanly, it fallbacks to int64 even
if it fails to guess kind.
Fixes#21708
Change-Id: I39a18cb2efbe4faa9becdcf53d5ac68dba180d46
Reviewed-on: https://go-review.googlesource.com/60510
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Done with grep & interactive search & replace, to double-check
replacements. Not many remained after CL 20022.
Fixes#18572
Change-Id: Idbe90ba3b584f9b9661d2bbd141607daaadfa41a
Reviewed-on: https://go-review.googlesource.com/45270
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
This is convenient for direct use of `go tool cgo`. We can also use it
from the go tool to reduce the length of the file names that cgo
generates.
Update #17070.
Change-Id: I8466a0a2cc68a732d17d07319e303497715bac8c
Reviewed-on: https://go-review.googlesource.com/32354
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Allow overriding default name of `pkg-config` tool via environment
variable PKG_CONFIG (same as used by autoconf pkg.m4 macros). This
facilitates easy cross-compilation of cgo code.
Original patch against Go <= 1.4 was written by
xnox_canonical <dimitri.ledkov@canonical.com> in 2014.
Source: https://codereview.appspot.com/104960043/Fixes#16253
Change-Id: I31c33ffc3ecbff65da31421e6188d092ab4fe7e4
Reviewed-on: https://go-review.googlesource.com/29991
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Add support for the context function set by runtime.SetCgoTraceback.
The context function was added in CL 17761, without support.
This CL is the support.
This CL has not been tested for real C code, as a working context
function for C code requires unwind support that does not seem to exist.
I wanted to get the CL out before the freeze.
I apologize for the length of this CL. It's mostly plumbing, but
unfortunately the plumbing is processor-specific.
Change-Id: I8ce11a0de9b3dafcc29efd2649d776e93bff0e90
Reviewed-on: https://go-review.googlesource.com/22508
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Add a C.CBytes function to copy a Go byte slice into C memory. This
returns an unsafe.Pointer, since that is what needs to be passed to
C.free, and the data is often opaque bytes anyway.
Fixes#14838
Change-Id: Ic7bc29637eb6f1f5ee409b3898c702a59833a85a
Reviewed-on: https://go-review.googlesource.com/20762
Reviewed-by: Ian Lance Taylor <iant@golang.org>
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>
This change adds support for Fortran files (.f, .F, .for, .f90) to the
go tool, in a similar fashion to Objective-C/C++. Only gfortran is
supported out of the box so far but leaves other Fortran compiler
toolchains the ability to pass the correct link options via CGO_LDFLAGS.
A simple test (misc/cgo/fortran) has been added and plugged into the
general test infrastructure. This test is only enabled when the $FC
environment variable is defined (or if 'gfortran' was found in $PATH.)
Derived from CL 4114.
Change-Id: Ifc855091942f95c6e9b17d91c17ceb4eee376408
Reviewed-on: https://go-review.googlesource.com/19670
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
You can not use cannot, but you cannot spell cannot can not.
Change-Id: I2f0971481a460804de96fd8c9e46a9cc62a3fc5b
Reviewed-on: https://go-review.googlesource.com/19772
Reviewed-by: Rob Pike <r@golang.org>
Fixes#13930.
Change-Id: I124b7d31d1f2be05b7f23dafd1e52d9f3f02f3f0
Reviewed-on: https://go-review.googlesource.com/18623
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This also fixes an unintended behavior where C's "complex float" and
"complex double" types were interchangeable with Go's "complex64" and
"complex128" types.
Fixes#13402.
Change-Id: I73f96d9a4772088d495073783c6982e9634430e8
Reviewed-on: https://go-review.googlesource.com/17208
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This implements part of the proposal in issue 12416 by adding dynamic
checks for passing pointers from Go to C. This code is intended to be
on at all times. It does not try to catch every case. It does not
implement checks on calling Go functions from C.
The new cgo checks may be disabled using GODEBUG=cgocheck=0.
Update #12416.
Change-Id: I48de130e7e2e83fb99a1e176b2c856be38a4d3c8
Reviewed-on: https://go-review.googlesource.com/16003
Reviewed-by: Russ Cox <rsc@golang.org>
The __uint128_t type appears in darwin/arm header files processed by
cgo -godefs in http://golang.org/cl/16045.
Change-Id: I666194c65dee8ea0ae933d2f02a3abe4581c4697
Reviewed-on: https://go-review.googlesource.com/16046
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Change-Id: Id6cb5e3d40e8a2ded6359aa7fcdc012861cc3994
Reviewed-on: https://go-review.googlesource.com/14545
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The one in misc/makerelease/makerelease.go is particularly bad and
probably warrants rotating our keys.
I didn't update old weekly notes, and reverted some changes involving
test code for now, since we're late in the Go 1.5 freeze. Otherwise,
the rest are all auto-generated changes, and all manually reviewed.
Change-Id: Ia2753576ab5d64826a167d259f48a2f50508792d
Reviewed-on: https://go-review.googlesource.com/12048
Reviewed-by: Rob Pike <r@golang.org>
This is a documentation fix that reflects the current reality.
Fixes#9673.
Change-Id: Ie436b277dfd1b68b13c67813d29c238d2c23b820
Reviewed-on: https://go-review.googlesource.com/11221
Reviewed-by: Russ Cox <rsc@golang.org>
Spell out what will happen if a declaration and definition is included
in the same file, should help people who run into duplicate symbol
errors and search for relevant keywords.
This edit is based on opening issue #11263 erroneously.
Change-Id: I0645a9433b8668d2ede9b9a3f6550d802c26388b
Reviewed-on: https://go-review.googlesource.com/11247
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The -exportheader option tells cgo to generate a header file declaring
expoted functions. The header file is only created if there are, in
fact, some exported functions, so it also serves as a signal as to
whether there were any.
In future CLs the go tool will use this option to install header files
for packages that use cgo and export functions.
Change-Id: I5b04357d453a9a8f0e70d37f8f18274cf40d74c9
Reviewed-on: https://go-review.googlesource.com/9796
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Also copy doc comments from Go code to _cgo_export.h.
This is a step toward installing this generated file when using
-buildmode=c-archive or c-shared, so that C code can #include it.
Change-Id: I3a243f7b386b58ec5c5ddb9a246bb9f9eddc5fb8
Reviewed-on: https://go-review.googlesource.com/9790
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
This is Part 2 of the change, see Part 1 here: in https://go-review.googlesource.com/#/c/7692/
Suggested by iant@, we use the library initialization entry point to:
- create a new OS thread and run the "regular" runtime init stack on
that thread
- return immediately from the main (i.e., loader) thread
- at the first CGO invocation, we wait for the runtime initialization
to complete.
The above mechanism is implemented only on linux_amd64. Next step is to
support it on linux_arm. Other platforms don't yet support shared library
compiling/linking, but we intend to use the same strategy there as well.
Change-Id: Ib2c81b1b83bee837134084b75a3beecfb8de6bf4
Reviewed-on: https://go-review.googlesource.com/8094
Run-TryBot: Srdjan Petrovic <spetrovic@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Now that there's no 6c compiler anymore, there's no need for cgo to
generate C headers that are compatible with it.
Fixes#9528
Change-Id: I43f53869719eb9a6065f1b39f66f060e604cbee0
Reviewed-on: https://go-review.googlesource.com/2482
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The gc toolchain no longer includes a C compiler, so mentions of "6c"
can be removed or replaced by 6g as appropriate. Similarly, some cgo
functions that previously generated C source output no longer need to.
Change-Id: I1ae6b02630cff9eaadeae6f3176c0c7824e8fbe5
Reviewed-on: https://go-review.googlesource.com/2391
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When go parses #cgo lines, expand ${SRCDIR} into the path to the
source directory. This allows options to be passed to the
compiler and linker that involve file paths relative to the
source code directory. Without the expansion the paths would be
invalid when the current working directory changes.
Fixes#7891Fixes#5428
Change-Id: I343a145a9771a5ccbaa958e4a1ecd1716fcae52d
Reviewed-on: https://go-review.googlesource.com/1756
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is a quick documentation change/clarification, as this
confused me before: in my own cgo-based projects, I currently have
identical #cgo directives in each relevant source file, and I notice
with go build -x that cgo is combining the directives, leading to
pkg-config invocations with the same package name (gtk+-3.0, in my
case) repeated several times, or on Mac OS X, LDFLAGS listing
-framework Foundation -framework AppKit multiple times. Since I am
about to add a CFLAGS as well, I checked the source to cmd/cgo and
go/build (where the work is actually done) to see if that still holds
true there. Hopefully other people who have made the same mistake I
have (I don't know if anyone has) can remove the excess declarations
now; this should make things slightly easier to manage as well.
LGTM=iant
R=golang-codereviews, gobot, iant
CC=golang-codereviews
https://golang.org/cl/91520046
The old approach to determining whether "name" was a type, constant,
or expression was to compile the C program
name;
and scan the errors and warnings generated by the compiler.
This requires looking for specific substrings in the errors and warnings,
which ties the implementation to specific compiler versions.
As compilers change their errors or drop warnings, cgo breaks.
This happens slowly but it does happen.
Clang in particular (now required on OS X) has a significant churn rate.
The new approach compiles a slightly more complex program
that is either valid C or not valid C depending on what kind of
thing "name" is. It uses only the presence or absence of an error
message on a particular line, not the error text itself. The program is:
// error if and only if name is undeclared
void f1(void) { typeof(name) *x; }
// error if and only if name is not a type
void f2(void) { name *x; }
// error if and only if name is not an integer constant
void f3(void) { enum { x = (name)*1 }; }
I had not been planning to do this until Go 1.3, because it is a
non-trivial change, but it fixes a real Xcode 5 problem in Go 1.2,
and the new code is easier to understand than the old code.
It should be significantly more robust.
Fixes#6596.
Fixes#6612.
R=golang-dev, r, james, iant
CC=golang-dev
https://golang.org/cl/15070043
In particular document that the Go tool will look for certain
file extensions and compile with them with either the C or the
C++ compiler.
Fixes#6393.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/13733043
Ian Lance Taylor
Sabin Mihai Rapan
Rens Rikkerink
Russ Cox
Keith Randall
Hiroshi Ioka
Brad Fitzpatrick
Boris Nagaev
James Bardin
kortschak
Josh Bleecher Snyder
Matthew Dempsky
Shenghou Ma
David Crawshaw
Alex Brainman
Andrey Petrov
Srdjan Petrovic
Carlos Castillo
Shenghou Ma
Pietro Gagliardi
Elias Naur