feat(import) Implement Trap (wasmer_trap in C)

[Hywan]

Fix #58.

When testing, I get this error:

=== RUN   TestImportTrap
fatal error: exitsyscall: syscall frame is no longer valid

goroutine 30 [syscall, locked to thread]:
runtime.cgocall(0x42a1990, 0xc000171b00, 0x5)
        /usr/local/Cellar/go/1.12.8/libexec/src/runtime/cgocall.go:128 +0x5b fp=0xc000171ad0 sp=0xc000171a98 pc=0x40059cb
github.com/wasmerio/go-ext-wasm/wasmer._Cfunc_wasmer_trap(0x4a0bc90, 0x4a0b0f0, 0x0)
        _cgo_gotypes.go:1012 +0x4d fp=0xc000171b00 sp=0xc000171ad0 pc=0x429009d
github.com/wasmerio/go-ext-wasm/wasmer.cWasmerTrap(0x4a0bc90, 0x434569b, 0x5, 0x1)
        /Users/hywan/Development/Wasmer/go-ext-wasm/wasmer/bridge.go:651 +0x4e fp=0xc000171b28 sp=0xc000171b00 pc=0x42910de
github.com/wasmerio/go-ext-wasm/wasmer.Trap(...)
        /Users/hywan/Development/Wasmer/go-ext-wasm/wasmer/import.go:354
command-line-arguments.trap(0x4a0bc90, 0x200000001, 0x7ffeefbfe0d8)
        /Users/hywan/Development/Wasmer/go-ext-wasm/wasmer/test/imports.go:300 +0x4f fp=0xc000171b58 sp=0xc000171b28 pc=0x429feaf
command-line-arguments._cgoexpwrap_cadc0fd800d6_trap(0x4a0bc90, 0x200000001, 0x0)
        _cgo_gotypes.go:229 +0x3b fp=0xc000171b80 sp=0xc000171b58 pc=0x429ca2b
runtime.call32(0x0, 0x7ffeefbfde10, 0x7ffeefbfdea8, 0x18)
        /usr/local/Cellar/go/1.12.8/libexec/src/runtime/asm_amd64.s:519 +0x3b fp=0xc000171bb0 sp=0xc000171b80 pc=0x405c06b
runtime: unexpected return pc for runtime.cgocallbackg1 called from 0xc000171c28
stack: frame={sp:0xc000171bb0, fp:0xc000171c28} stack=[0xc000171000,0xc000172000)
000000c000171ab0:  0000000004a0b0f0  00000000045c4c00
000000c000171ac0:  000000c000171af0  000000000429009d <github.com/wasmerio/go-ext-wasm/wasmer._Cfunc_wasmer_trap+77>
000000c000171ad0:  00000000042a1990  000000c000171b00
000000c000171ae0:  0000000000000005  000000c000171b00
000000c000171af0:  000000c000171b18  00000000042910de <github.com/wasmerio/go-ext-wasm/wasmer.cWasmerTrap+78>
000000c000171b00:  0000000004a0bc90  0000000004a0b0f0
000000c000171b10:  0000000000000000  000000c000171b48
000000c000171b20:  000000000429feaf <command-line-arguments.trap+79>  0000000004a0bc90
000000c000171b30:  000000000434569b  0000000000000005
000000c000171b40:  0000000000000001  000000c000171b70
000000c000171b50:  000000000429ca2b <command-line-arguments._cgoexpwrap_cadc0fd800d6_trap+59>  0000000004a0bc90
000000c000171b60:  0000000200000001  00007ffeefbfe0d8
000000c000171b70:  000000c000171ba0  000000000405c06b <runtime.call32+59>
000000c000171b80:  0000000004a0bc90  0000000200000001
000000c000171b90:  0000000000000000  000000c000171bb8
000000c000171ba0:  000000c000171c18  0000000004005d37 <runtime.cgocallbackg1+375>
000000c000171bb0: <0000000000000000  00007ffeefbfde10
000000c000171bc0:  00007ffeefbfdea8  0000000000000018
000000c000171bd0:  000000c0000bac00  0000000004006b55 <runtime.cgoIsGoPointer+37>
000000c000171be0:  000000000435b600  000000c000171c18
000000c000171bf0:  01000000040381d4  000000c000084f00
000000c000171c00:  0000000200000003  000000c000084f00
000000c000171c10:  000000c000084f00  000000000402f8a7 <runtime.fatalthrow+87>
000000c000171c20: !000000c000171c28 >000000000405aa20 <runtime.fatalthrow.func1+0>
000000c000171c30:  000000c000084f00  000000000402f6d2 <runtime.throw+114>
000000c000171c40:  000000c000171c58  000000c000171c78
000000c000171c50:  000000000402f6d2 <runtime.throw+114>  000000c000171c60
000000c000171c60:  000000000405a9a0 <runtime.throw.func1+0>  000000000435289e
000000c000171c70:  000000000000002d  000000c000171ca8
000000c000171c80:  00000000040382b7 <runtime.exitsyscall+647>  000000000435289e
000000c000171c90:  000000000000002d  00000000045c4c00
000000c000171ca0:  000000c000171cb8  000000c000171ce0
000000c000171cb0:  0000000004005a0e <runtime.cgocall+158>  00000000042a1530
000000c000171cc0:  000000c000171d20  0000000000000000
000000c000171cd0:  00000000000000a2  00000000045c4c00
000000c000171ce0:  000000c000171d10  000000000428f3bd <github.com/wasmerio/go-ext-wasm/wasmer._Cfunc_wasmer_instance_call+77>
000000c000171cf0:  00000000042a1530  000000c000171d20
000000c000171d00:  0000000000000004  000000c000171d20
000000c000171d10:  000000c000171ea8  00000000042917e4 <github.com/wasmerio/go-ext-wasm/wasmer.getExportsFromInstance.func1+820>
000000c000171d20:  0000000004a0b6c0
runtime.cgocallbackg1(0x405aa20)
        /usr/local/Cellar/go/1.12.8/libexec/src/runtime/cgocall.go:314 +0x177 fp=0xc000171c28 sp=0xc000171bb0 pc=0x4005d37
created by testing.(*T).Run
        /usr/local/Cellar/go/1.12.8/libexec/src/testing/testing.go:916 +0x35a

goroutine 1 [chan receive]:
testing.(*T).Run(0xc00014a500, 0x4347c08, 0xe, 0x435b218, 0x1)
        /usr/local/Cellar/go/1.12.8/libexec/src/testing/testing.go:917 +0x381
testing.runTests.func1(0xc00012a000)
        /usr/local/Cellar/go/1.12.8/libexec/src/testing/testing.go:1157 +0x78
testing.tRunner(0xc00012a000, 0xc0000cfe30)
        /usr/local/Cellar/go/1.12.8/libexec/src/testing/testing.go:865 +0xc0
testing.runTests(0xc0000b23e0, 0x45bf920, 0x33, 0x33, 0x0)
        /usr/local/Cellar/go/1.12.8/libexec/src/testing/testing.go:1155 +0x2a9
testing.(*M).Run(0xc000126000, 0x0)
        /usr/local/Cellar/go/1.12.8/libexec/src/testing/testing.go:1072 +0x162
main.main()
        _testmain.go:142 +0x13e
FAIL    command-line-arguments  0.226s

I think it's because we use setjmp to raise an error, and Go also uses it for another purpose. Need to investigate.

[rusenask]

Hi, is there any progress on this? Would current solution involve separately executing Go code that runs wasmer via cmd exec to avoid panics?

[Hywan]

Actually we need polymorphic host function to continue this PR. We are working on it.

[rusenask]

hi, was this blocked by wasmerio/wasmer#1305 ?

[Hywan]

Nop, but we are actually unblocked by the new DynamicFunc API!

[Hywan]

It's going to be fixed by the rewrite.