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2023-05-12misc/cgo: move registerCgoTests tests to cmd/cgo/internalAustin Clements
This moves the remaining cgo tests. For #37486. Change-Id: I99dea5a312a1974de338461a8b02242e5c1bae62 Reviewed-on: https://go-review.googlesource.com/c/go/+/492721 Run-TryBot: Austin Clements <austin@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Bryan Mills <bcmills@google.com>
2021-02-19runtime: unify asmcgocall and systemstack traceback setupRuss Cox
Both asmcgocall and systemstack need to save the calling Go code's context for use by traceback, but they do it differently. Systemstack's appraoch is better, because it doesn't require a special case in traceback. So make them both use that. While we are here, the fake mstart caller in systemstack is no longer needed and can be removed. (traceback knows to stop in systemstack because of the writes to SP.) Also remove the fake mstarts in sys_windows_*.s. And while we are there, fix the control flow guard code in sys_windows_arm.s. The current code is using pointers to a stack frame that technically is gone once we hit the RET instruction. Clearly it's working OK, but better not to depend on data below SP being preserved, even for just a few instructions. Store the value we need in other registers instead. (This code is only used for pushing a sigpanic call, which does not actually return to the site of the fault and therefore doesn't need to preserve any of the registers.) This CL is part of a stack adding windows/arm64 support (#36439), intended to land in the Go 1.17 cycle. This CL is, however, not windows/arm64-specific. It is cleanup meant to make the port (and future ports) easier. Change-Id: Id1e3ef5e54f7ad786e4b87043f2626eba7c3bbd9 Reviewed-on: https://go-review.googlesource.com/c/go/+/288799 Trust: Russ Cox <rsc@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-10-26runtime,cmd/cgo: simplify C -> Go call pathAustin Clements
This redesigns the way calls work from C to exported Go functions. It removes several steps from the call path, makes cmd/cgo no longer sensitive to the Go calling convention, and eliminates the use of reflectcall from cgo. In order to avoid generating a large amount of FFI glue between the C and Go ABIs, the cgo tool has long depended on generating a C function that marshals the arguments into a struct, and then the actual ABI switch happens in functions with fixed signatures that simply take a pointer to this struct. In a way, this CL simply pushes this idea further. Currently, the cgo tool generates this argument struct in the exact layout of the Go stack frame and depends on reflectcall to unpack it into the appropriate Go call (even though it's actually reflectcall'ing a function generated by cgo). In this CL, we decouple this struct from the Go stack layout. Instead, cgo generates a Go function that takes the struct, unpacks it, and calls the exported function. Since this generated function has a generic signature (like the rest of the call path), we don't need reflectcall and can instead depend on the Go compiler itself to implement the call to the exported Go function. One complication is that syscall.NewCallback on Windows, which converts a Go function into a C function pointer, depends on cgocallback's current dynamic calling approach since the signatures of the callbacks aren't known statically. For this specific case, we continue to depend on reflectcall. Really, the current approach makes some overly simplistic assumptions about translating the C ABI to the Go ABI. Now we're at least in a much better position to do a proper ABI translation. For comparison, the current cgo call path looks like: GoF (generated C function) -> crosscall2 (in cgo/asm_*.s) -> _cgoexp_GoF (generated Go function) -> cgocallback (in asm_*.s) -> cgocallback_gofunc (in asm_*.s) -> cgocallbackg (in cgocall.go) -> cgocallbackg1 (in cgocall.go) -> reflectcall (in asm_*.s) -> _cgoexpwrap_GoF (generated Go function) -> p.GoF Now the call path looks like: GoF (generated C function) -> crosscall2 (in cgo/asm_*.s) -> cgocallback (in asm_*.s) -> cgocallbackg (in cgocall.go) -> cgocallbackg1 (in cgocall.go) -> _cgoexp_GoF (generated Go function) -> p.GoF Notably: 1. We combine _cgoexp_GoF and _cgoexpwrap_GoF and move the combined operation to the end of the sequence. This combined function also handles reflectcall's previous role. 2. We combined cgocallback and cgocallback_gofunc since the only purpose of having both was to convert a raw PC into a Go function value. We instead construct the Go function value in cgocallbackg1. 3. cgocallbackg1 no longer reaches backwards through the stack to get the arguments to cgocallback_gofunc. Instead, we just pass the arguments down. 4. Currently, we need an explicit msanwrite to mark the results struct as written because reflectcall doesn't do this. Now, the results are written by regular Go assignments, so the Go compiler generates the necessary MSAN annotations. This also means we no longer need to track the size of the arguments frame. Updates #40724, since now we don't need to teach cgo about the register ABI or change how it uses reflectcall. Change-Id: I7840489a2597962aeb670e0c1798a16a7359c94f Reviewed-on: https://go-review.googlesource.com/c/go/+/258938 Trust: Austin Clements <austin@google.com> Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2019-03-25cmd/compile: use existing instructions instead of nops for inline marksKeith Randall
Instead of always inserting a nop to use as the target of an inline mark, see if we can instead find an instruction we're issuing anyway with the correct line number, and use that instruction. That way, we don't need to issue a nop. Makes cmd/go 0.3% smaller. Update #29571 Change-Id: If6cfc93ab3352ec2c6e0878f8074a3bf0786b2f8 Reviewed-on: https://go-review.googlesource.com/c/go/+/158021 Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2019-02-24misc/cgo/test: fix tests in module modeBryan C. Mills
This change preserves the ability to test misc/cgo/test in GOPATH mode, at the cost of indirection through a 'go test' subprocess. Updates #30228 Change-Id: I08de855e62278d30fa622b2f7478e43dd2ab0e96 Reviewed-on: https://go-review.googlesource.com/c/163418 Run-TryBot: Bryan C. Mills <bcmills@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-12-28cmd/compile,runtime: redo mid-stack inlining tracebacksKeith Randall
Work involved in getting a stack trace is divided between runtime.Callers and runtime.CallersFrames. Before this CL, runtime.Callers returns a pc per runtime frame. runtime.CallersFrames is responsible for expanding a runtime frame into potentially multiple user frames. After this CL, runtime.Callers returns a pc per user frame. runtime.CallersFrames just maps those to user frame info. Entries in the result of runtime.Callers are now pcs of the calls (or of the inline marks), not of the instruction just after the call. Fixes #29007 Fixes #28640 Update #26320 Change-Id: I1c9567596ff73dc73271311005097a9188c3406f Reviewed-on: https://go-review.googlesource.com/c/152537 Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
2018-10-06all: fix a bunch of misspellingsIgor Zhilianin
Change-Id: If2954bdfc551515403706b2cd0dde94e45936e08 GitHub-Last-Rev: d4cfc41a5504cf10befefdb881d4c45986a1d1f8 GitHub-Pull-Request: golang/go#28049 Reviewed-on: https://go-review.googlesource.com/c/140299 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-19cmd/cgo: always use a function literal for pointer checkingIan Lance Taylor
The pointer checking code needs to know the exact type of the parameter expected by the C function, so that it can use a type assertion to convert the empty interface returned by cgoCheckPointer to the correct type. Previously this was done by using a type conversion, but that meant that the code accepted arguments that were convertible to the parameter type, rather than arguments that were assignable as in a normal function call. In other words, some code that should not have passed type checking was accepted. This CL changes cgo to always use a function literal for pointer checking. Now the argument is passed to the function literal, which has the correct argument type, so type checking is performed just as for a function call as it should be. Since we now always use a function literal, simplify the checking code to run as a statement by itself. It now no longer needs to return a value, and we no longer need a type assertion. This does have the cost of introducing another function call into any call to a C function that requires pointer checking, but the cost of the additional call should be minimal compared to the cost of pointer checking. Fixes #16591. Change-Id: I220165564cf69db9fd5f746532d7f977a5b2c989 Reviewed-on: https://go-review.googlesource.com/31233 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2015-11-29cmd/cgo: make the char * pointer in GoString constIan Lance Taylor
This makes it more convenient for C code to use GoString with string constants. Since Go string values are immutable, the const qualifier is appropriate in C. Change-Id: I5fb3cdce2ce5079f1f0467a1544bb3a1eb27b811 Reviewed-on: https://go-review.googlesource.com/17067 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
2015-11-19cmd/cgo, runtime: exported Go functions can't return a Go pointerIan Lance Taylor
Update #12416. Change-Id: Iccbcb12709d1ca9bea87274f44f93cfcebadb070 Reviewed-on: https://go-review.googlesource.com/17048 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-11-10cmd/cgo, runtime: add checks for passing pointers from Go to CIan Lance Taylor
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>
2015-10-13misc/cgo/test: fix go vet warningsIan Lance Taylor
Fixes these warnings from go vet: buildid_linux.go:25: no formatting directive in Fatalf call callback.go:180: arg pc[i] for printf verb %p of wrong type: uintptr env.go:34: possible misuse of unsafe.Pointer issue7665.go:22: possible misuse of unsafe.Pointer Change-Id: I83811b9c10c617139713a626b4a34ab05564d4fe Reviewed-on: https://go-review.googlesource.com/15802 Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-06-19runtime: rename cgocall_errno and asmcgocall_errno into cgocall and asmcgocallAlex Brainman
Change-Id: I5917bea8bb35b0e725dcc56a68f3a70137cfc180 Reviewed-on: https://go-review.googlesource.com/9387 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-17runtime: delete cgo_allocateRuss Cox
This memory is untyped and can't be used anymore. The next version of SWIG won't need it. Change-Id: I592b287c5f5186975ee09a9b28d8efe3b57134e7 Reviewed-on: https://go-review.googlesource.com/8956 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-01-06misc/cgo: disable TestAllocateFromC in wbshadow modeRuss Cox
This test is doing pointer graph manipulation from C, and we cannot support that with concurrent GC. The wbshadow mode correctly diagnoses missing write barriers. Disable the test in that mode for now. There is a bigger issue behind it, namely SWIG, but for now we are focused on making all.bash pass with wbshadow enabled. Change-Id: I55891596d4c763e39b74082191d4a5fac7161642 Reviewed-on: https://go-review.googlesource.com/2346 Reviewed-by: Minux Ma <minux@golang.org> Reviewed-by: Rick Hudson <rlh@golang.org>
2015-01-06reflect: add write barriersRuss Cox
Use typedmemmove, typedslicecopy, and adjust reflect.call to execute the necessary write barriers. Found with GODEBUG=wbshadow=2 mode. Eventually that will run automatically, but right now it still detects other missing write barriers. Change-Id: Iec5b5b0c1be5589295e28e5228e37f1a92e07742 Reviewed-on: https://go-review.googlesource.com/2312 Reviewed-by: Keith Randall <khr@golang.org>
2014-12-24misc/cgo/test: get rid of the backdoor packageShenghou Ma
For Go 1.5, we can use go:linkname rather than assembly thunk for gc. Gccgo already has support for //extern. Change-Id: I5505aa247dd5b555112f7261ed2f192c81cf0bdf Signed-off-by: Shenghou Ma <minux@golang.org> Reviewed-on: https://go-review.googlesource.com/1888 Reviewed-by: Russ Cox <rsc@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2014-09-25cgo: adjust return value location to account for stack copies.Keith Randall
During a cgo call, the stack can be copied. This copy invalidates the pointer that cgo has into the return value area. To fix this problem, pass the address of the location containing the stack top value (which is in the G struct). For cgo functions which return values, read the stktop before and after the cgo call to compute the adjustment necessary to write the return value. Fixes #8771 LGTM=iant, rsc R=iant, rsc, khr CC=golang-codereviews https://golang.org/cl/144130043
2014-09-16runtime: remove untyped allocation of ParForRuss Cox
Now it's two allocations. I don't see much downside to that, since the two pieces were in different cache lines anyway. Rename 'conservative' to 'cgo_conservative_type' and make clear that _cgo_allocate is the only allowed user. This depends on CL 141490043, which removes the other use of conservative (in defer). LGTM=dvyukov, iant R=khr, dvyukov, iant CC=golang-codereviews, rlh https://golang.org/cl/139610043
2014-09-05runtime: use reflect.call during panic instead of newstackcallRuss Cox
newstackcall creates a new stack segment, and we want to be able to throw away all that code. LGTM=khr R=khr, iant CC=dvyukov, golang-codereviews, r https://golang.org/cl/139270043
2014-09-04runtime: refactor/fix asmcgocall/asmcgocall_errnoRuss Cox
Instead of making asmcgocall call asmcgocall_errno, make both load args into registers and call a shared assembly function. On amd64, this costs 1 word in the asmcgocall_errno path but saves 3 words in the asmcgocall path, and the latter is what happens on critical nosplit paths on Windows. On arm, this fixes build failures: asmcgocall was writing the arguments for asmcgocall_errno into the wrong place on the stack. Passing them in registers avoids the decision entirely. On 386, this isn't really needed, since the nosplit paths have twice as many words to work with, but do it for consistency. Update #8635 Fixes arm build (except GOARM=5). TBR=iant CC=golang-codereviews https://golang.org/cl/134390043
2014-09-03cmd/cgo, runtime: write cgo stub wrappers in Go, not CRuss Cox
LGTM=alex.brainman, iant R=golang-codereviews, alex.brainman, iant CC=dvyukov, golang-codereviews, khr, r https://golang.org/cl/139070043
2013-10-09runtime/cgo: mark callback functions as NOSPLITIan Lance Taylor
R=golang-dev, minux.ma CC=golang-dev https://golang.org/cl/14448044
2013-08-05runtime: Use old reflect.call implementation from cgo.Keith Randall
Basically a partial rollback of 12053043 until I can figure out what is really going on. Fixes bug 6051. R=golang-dev CC=golang-dev https://golang.org/cl/12496043
2013-08-02runtime: reimplement reflect.call to not use stack splitting.Keith Randall
R=golang-dev, r, khr, rsc CC=golang-dev https://golang.org/cl/12053043
2013-07-29runtime: do not split stacks in syscall statusDmitriy Vyukov
Split stack checks (morestack) corrupt g->sched, but g->sched must be preserved consistent for GC/traceback. The change implements runtime.notetsleepg function, which does entersyscall/exitsyscall and is carefully arranged to not call any split functions in between. R=rsc CC=golang-dev https://golang.org/cl/11575044
2013-07-25cmd/cgo: gccgo fixesIan Lance Taylor
Don't require a full-scale callback for calls to the special prologue functions. Always use a simple wrapper function for C functions, so that we can handle static functions defined in the import "C" comment. Disable a test that relies on gc-specific function names. Fixes #5905. R=golang-dev, rsc CC=golang-dev https://golang.org/cl/11406047
2013-07-22misc/cgo/test: add test for cgo callbacks with different amount of stack ↵Dmitriy Vyukov
space available R=golang-dev, bradfitz CC=golang-dev https://golang.org/cl/11677043
2013-06-12runtime: add lr, ctxt, ret to GobufRuss Cox
Add gostartcall and gostartcallfn. The old gogocall = gostartcall + gogo. The old gogocallfn = gostartcallfn + gogo. R=dvyukov, minux.ma CC=golang-dev https://golang.org/cl/10036044
2013-03-26runtime: ensure forward progress when unwinding an arm stack frameCarl Shapiro
The arm gentraceback mishandled frame linkage values pointing to the assembly return function. This function is special as its frame size is zero and it contains only one instruction. These conditions would preserve the frame pointer and result in an off by one error when unwinding the caller. Fixes #5124 R=golang-dev, bradfitz CC=golang-dev https://golang.org/cl/8023043
2013-03-25runtime: store asmcgocall return PC where the ARM unwind expects itCarl Shapiro
The ARM implementation of runtime.cgocallback_gofunc diverged from the calling convention by leaving a word of garbage at the top of the stack and storing the return PC above the locals. This change stores the return PC at the top of the stack and removes the save area above the locals. Update #5124 This CL fixes first part of the ARM issues and added the unwind test. R=golang-dev, bradfitz, minux.ma, cshapiro, rsc CC=golang-dev https://golang.org/cl/7728045
2012-10-30gofmt: apply gofmt -w src miscRobert Griesemer
Remove trailing whitespace in comments. No other changes. R=r CC=golang-dev https://golang.org/cl/6815053
2012-03-06misc/cgo: re-enable some testsRuss Cox
The testso directory still needs to be enabled. R=golang-dev, r CC=golang-dev https://golang.org/cl/5731048
2012-01-24test: Add the usual Copyright notice.Olivier Duperray
Fixes #2759. R=golang-dev, rsc CC=golang-dev https://golang.org/cl/5570053
2011-08-30cgo: fix GoBytesGustavo Niemeyer
R=golang-dev, adg CC=golang-dev https://golang.org/cl/4956051
2011-05-02misc/cgo/test: run testsRuss Cox
The new gotest ignores Test functions outside *_test.go files (the old shell script allowed them), so replace one clumsy hack with another. The root problem is that the package makefiles only know how to run cgo for source files in the package proper, not for test files. Making it work for test files is probably more trouble than it's worth. R=bradfitz CC=golang-dev https://golang.org/cl/4452060
2011-03-22go/printer, gofmt: simplify struct formatting and respect line breaksRobert Griesemer
Also: gofmt src misc Fixes #1627. R=rsc CC=golang-dev https://golang.org/cl/4303042
2011-03-07runtime: scheduler, cgo reorganizationRuss Cox
* Change use of m->g0 stack (aka scheduler stack). * Provide runtime.mcall(f) to invoke f() on m->g0 stack. * Replace scheduler loop entry with runtime.mcall(schedule). Runtime.mcall eliminates the need for fake scheduler states that exist just to run a bit of code on the m->g0 stack (Grecovery, Gstackalloc). The elimination of the scheduler as a loop that stops and starts using gosave and gogo fixes a bad interaction with the way cgo uses the m->g0 stack. Cgo runs external (gcc-compiled) C functions on that stack, and then when calling back into Go, it sets m->g0->sched.sp below the added call frames, so that other uses of m->g0's stack will not interfere with those frames. Unfortunately, gogo (longjmp) back to the scheduler loop at this point would end up running scheduler with the lower sp, which no longer points at a valid stack frame for a call to scheduler. If scheduler then wrote any function call arguments or local variables to where it expected the stack frame to be, it would overwrite other data on the stack. I realized this possibility while debugging a problem with calling complex Go code in a Go -> C -> Go cgo callback. This wasn't the bug I was looking for, it turns out, but I believe it is a real bug nonetheless. Switching to runtime.mcall, which only adds new frames to the stack and never jumps into functions running in existing ones, fixes this bug. * Move cgo-related code out of proc.c into cgocall.c. * Add very large comment describing cgo call sequences. * Simpilify, regularize cgo function implementations and names. * Add test suite as misc/cgo/test. Now the Go -> C path calls cgocall, which calls asmcgocall, and the C -> Go path calls cgocallback, which calls cgocallbackg. The shuffling, which affects mainly the callback case, moves most of the callback implementation to cgocallback running on the m->curg stack (not the m->g0 scheduler stack) and only while accounted for with $GOMAXPROCS (between calls to exitsyscall and entersyscall). The previous callback code did not block in startcgocallback's approximation to exitsyscall, so if, say, the garbage collector were running, it would still barge in and start doing things like call malloc. Similarly endcgocallback's approximation of entersyscall did not call matchmg to kick off new OS threads when necessary, which caused the bug in issue 1560. Fixes #1560. R=iant CC=golang-dev https://golang.org/cl/4253054