diff options
Diffstat (limited to 'tools/go_marshal')
| -rw-r--r-- | tools/go_marshal/README.md | 8 | ||||
| -rw-r--r-- | tools/go_marshal/gomarshal/generator.go | 4 | ||||
| -rw-r--r-- | tools/go_marshal/gomarshal/generator_interfaces_struct.go | 28 | ||||
| -rw-r--r-- | tools/go_marshal/marshal/marshal.go | 36 | ||||
| -rw-r--r-- | tools/go_marshal/primitive/primitive.go | 72 | ||||
| -rw-r--r-- | tools/go_marshal/test/BUILD | 2 |
6 files changed, 110 insertions, 40 deletions
diff --git a/tools/go_marshal/README.md b/tools/go_marshal/README.md index 4886efddf..68d759083 100644 --- a/tools/go_marshal/README.md +++ b/tools/go_marshal/README.md @@ -9,11 +9,9 @@ automatically generating code to marshal go data structures to memory. `binary.Marshal` by moving the go runtime reflection necessary to marshal a struct to compile-time. -`go_marshal` automatically generates implementations for `abi.Marshallable` and -`safemem.{Reader,Writer}`. Call-sites for serialization (typically syscall -implementations) can directly invoke `safemem.Reader.ReadToBlocks` and -`safemem.Writer.WriteFromBlocks`. Data structures that require custom -serialization will have manual implementations for these interfaces. +`go_marshal` automatically generates implementations for `marshal.Marshallable` +and `safemem.{Reader,Writer}`. Data structures that require custom serialization +will have manual implementations for these interfaces. Data structures can be flagged for code generation by adding a struct-level comment `// +marshal`. diff --git a/tools/go_marshal/gomarshal/generator.go b/tools/go_marshal/gomarshal/generator.go index 177013dbb..19bcd4e6a 100644 --- a/tools/go_marshal/gomarshal/generator.go +++ b/tools/go_marshal/gomarshal/generator.go @@ -413,13 +413,13 @@ func (g *Generator) Run() error { for _, t := range g.collectMarshallableTypes(a, fsets[i]) { impl := g.generateOne(t, fsets[i]) // Collect Marshallable types referenced by the generated code. - for ref, _ := range impl.ms { + for ref := range impl.ms { ms[ref] = struct{}{} } impls = append(impls, impl) // Collect imports referenced by the generated code and add them to // the list of imports we need to copy to the generated code. - for name, _ := range impl.is { + for name := range impl.is { if !g.imports.markUsed(name) { panic(fmt.Sprintf("Generated code for '%s' referenced a non-existent import with local name '%s'. Either go-marshal needs to add an import to the generated file, or a package in an input source file has a package name differ from the final component of its path, which go-marshal doesn't know how to detect; use an import alias to work around this limitation.", impl.typeName(), name)) } diff --git a/tools/go_marshal/gomarshal/generator_interfaces_struct.go b/tools/go_marshal/gomarshal/generator_interfaces_struct.go index 9cd3c9579..4b9cea08a 100644 --- a/tools/go_marshal/gomarshal/generator_interfaces_struct.go +++ b/tools/go_marshal/gomarshal/generator_interfaces_struct.go @@ -268,6 +268,10 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) { g.emit("// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.\n") g.emit("func (%s *%s) MarshalUnsafe(dst []byte) {\n", g.r, g.typeName()) g.inIndent(func() { + fallback := func() { + g.emit("// Type %s doesn't have a packed layout in memory, fallback to MarshalBytes.\n", g.typeName()) + g.emit("%s.MarshalBytes(dst)\n", g.r) + } if thisPacked { g.recordUsedImport("safecopy") g.recordUsedImport("unsafe") @@ -277,16 +281,13 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) { g.emit("safecopy.CopyIn(dst, unsafe.Pointer(%s))\n", g.r) }) g.emit("} else {\n") - g.inIndent(func() { - g.emit("%s.MarshalBytes(dst)\n", g.r) - }) + g.inIndent(fallback) g.emit("}\n") } else { g.emit("safecopy.CopyIn(dst, unsafe.Pointer(%s))\n", g.r) } } else { - g.emit("// Type %s doesn't have a packed layout in memory, fallback to MarshalBytes.\n", g.typeName()) - g.emit("%s.MarshalBytes(dst)\n", g.r) + fallback() } }) g.emit("}\n\n") @@ -294,6 +295,10 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) { g.emit("// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.\n") g.emit("func (%s *%s) UnmarshalUnsafe(src []byte) {\n", g.r, g.typeName()) g.inIndent(func() { + fallback := func() { + g.emit("// Type %s doesn't have a packed layout in memory, fallback to UnmarshalBytes.\n", g.typeName()) + g.emit("%s.UnmarshalBytes(src)\n", g.r) + } if thisPacked { g.recordUsedImport("safecopy") g.recordUsedImport("unsafe") @@ -303,16 +308,13 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) { g.emit("safecopy.CopyOut(unsafe.Pointer(%s), src)\n", g.r) }) g.emit("} else {\n") - g.inIndent(func() { - g.emit("%s.UnmarshalBytes(src)\n", g.r) - }) + g.inIndent(fallback) g.emit("}\n") } else { g.emit("safecopy.CopyOut(unsafe.Pointer(%s), src)\n", g.r) } } else { - g.emit("// Type %s doesn't have a packed layout in memory, fall back to UnmarshalBytes.\n", g.typeName()) - g.emit("%s.UnmarshalBytes(src)\n", g.r) + fallback() } }) g.emit("}\n\n") @@ -463,8 +465,10 @@ func (g *interfaceGenerator) emitMarshallableSliceForStruct(st *ast.StructType, }) g.emit("}\n\n") - g.emit("// Handle any final partial object.\n") - g.emit("if length < size*count && length%size != 0 {\n") + g.emit("// Handle any final partial object. buf is guaranteed to be long enough for the\n") + g.emit("// final element, but may not contain valid data for the entire range. This may\n") + g.emit("// result in unmarshalling zero values for some parts of the object.\n") + g.emit("if length%size != 0 {\n") g.inIndent(func() { g.emit("idx := limit\n") g.emit("dst[idx].UnmarshalBytes(buf[size*idx:size*(idx+1)])\n") diff --git a/tools/go_marshal/marshal/marshal.go b/tools/go_marshal/marshal/marshal.go index cb2166252..85b196f08 100644 --- a/tools/go_marshal/marshal/marshal.go +++ b/tools/go_marshal/marshal/marshal.go @@ -58,18 +58,12 @@ type Marshallable interface { // likely make use of the type of these fields). SizeBytes() int - // MarshalBytes serializes a copy of a type to dst. dst may be smaller than - // SizeBytes(), which results in a part of the struct being marshalled. Note - // that this may have unexpected results for non-packed types, as implicit - // padding needs to be taken into account when reasoning about how much of - // the type is serialized. + // MarshalBytes serializes a copy of a type to dst. + // Precondition: dst must be at least SizeBytes() in length. MarshalBytes(dst []byte) - // UnmarshalBytes deserializes a type from src. src may be smaller than - // SizeBytes(), which results in a partially deserialized struct. Note that - // this may have unexpected results for non-packed types, as implicit - // padding needs to be taken into account when reasoning about how much of - // the type is deserialized. + // UnmarshalBytes deserializes a type from src. + // Precondition: src must be at least SizeBytes() in length. UnmarshalBytes(src []byte) // Packed returns true if the marshalled size of the type is the same as the @@ -89,8 +83,8 @@ type Marshallable interface { // representation to the dst buffer. This is only safe to do when the type // has no implicit padding, see Marshallable.Packed. When Packed would // return false, MarshalUnsafe should fall back to the safer but slower - // MarshalBytes. dst may be smaller than SizeBytes(), see comment for - // MarshalBytes for implications. + // MarshalBytes. + // Precondition: dst must be at least SizeBytes() in length. MarshalUnsafe(dst []byte) // UnmarshalUnsafe deserializes a type by directly copying to the underlying @@ -99,8 +93,8 @@ type Marshallable interface { // This allows much faster unmarshalling of types which have no implicit // padding, see Marshallable.Packed. When Packed would return false, // UnmarshalUnsafe should fall back to the safer but slower unmarshal - // mechanism implemented in UnmarshalBytes. src may be smaller than - // SizeBytes(), see comment for UnmarshalBytes for implications. + // mechanism implemented in UnmarshalBytes. + // Precondition: src must be at least SizeBytes() in length. UnmarshalUnsafe(src []byte) // CopyIn deserializes a Marshallable type from a task's memory. This may @@ -149,14 +143,16 @@ type Marshallable interface { // // Generates four additional functions for marshalling slices of Foos like this: // -// // MarshalUnsafeFooSlice is like Foo.MarshalUnsafe, buf for a []Foo. It's -// // more efficient that repeatedly calling calling Foo.MarshalUnsafe over a -// // []Foo in a loop. +// // MarshalUnsafeFooSlice is like Foo.MarshalUnsafe, buf for a []Foo. It +// // might be more efficient that repeatedly calling Foo.MarshalUnsafe +// // over a []Foo in a loop if the type is Packed. +// // Preconditions: dst must be at least len(src)*Foo.SizeBytes() in length. // func MarshalUnsafeFooSlice(src []Foo, dst []byte) (int, error) { ... } // -// // UnmarshalUnsafeFooSlice is like Foo.UnmarshalUnsafe, buf for a []Foo. It's -// // more efficient that repeatedly calling calling Foo.UnmarshalUnsafe over a -// // []Foo in a loop. +// // UnmarshalUnsafeFooSlice is like Foo.UnmarshalUnsafe, buf for a []Foo. It +// // might be more efficient that repeatedly calling Foo.UnmarshalUnsafe +// // over a []Foo in a loop if the type is Packed. +// // Preconditions: src must be at least len(dst)*Foo.SizeBytes() in length. // func UnmarshalUnsafeFooSlice(dst []Foo, src []byte) (int, error) { ... } // // // CopyFooSliceIn copies in a slice of Foo objects from the task's memory. diff --git a/tools/go_marshal/primitive/primitive.go b/tools/go_marshal/primitive/primitive.go index ebcf130ae..d93edda8b 100644 --- a/tools/go_marshal/primitive/primitive.go +++ b/tools/go_marshal/primitive/primitive.go @@ -17,10 +17,22 @@ package primitive import ( + "io" + "gvisor.dev/gvisor/pkg/usermem" "gvisor.dev/gvisor/tools/go_marshal/marshal" ) +// Int8 is a marshal.Marshallable implementation for int8. +// +// +marshal slice:Int8Slice:inner +type Int8 int8 + +// Uint8 is a marshal.Marshallable implementation for uint8. +// +// +marshal slice:Uint8Slice:inner +type Uint8 uint8 + // Int16 is a marshal.Marshallable implementation for int16. // // +marshal slice:Int16Slice:inner @@ -51,6 +63,66 @@ type Int64 int64 // +marshal slice:Uint64Slice:inner type Uint64 uint64 +// ByteSlice is a marshal.Marshallable implementation for []byte. +// This is a convenience wrapper around a dynamically sized type, and can't be +// embedded in other marshallable types because it breaks assumptions made by +// go-marshal internals. It violates the "no dynamically-sized types" +// constraint of the go-marshal library. +type ByteSlice []byte + +// SizeBytes implements marshal.Marshallable.SizeBytes. +func (b *ByteSlice) SizeBytes() int { + return len(*b) +} + +// MarshalBytes implements marshal.Marshallable.MarshalBytes. +func (b *ByteSlice) MarshalBytes(dst []byte) { + copy(dst, *b) +} + +// UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes. +func (b *ByteSlice) UnmarshalBytes(src []byte) { + copy(*b, src) +} + +// Packed implements marshal.Marshallable.Packed. +func (b *ByteSlice) Packed() bool { + return false +} + +// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe. +func (b *ByteSlice) MarshalUnsafe(dst []byte) { + b.MarshalBytes(dst) +} + +// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe. +func (b *ByteSlice) UnmarshalUnsafe(src []byte) { + b.UnmarshalBytes(src) +} + +// CopyIn implements marshal.Marshallable.CopyIn. +func (b *ByteSlice) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) { + return task.CopyInBytes(addr, *b) +} + +// CopyOut implements marshal.Marshallable.CopyOut. +func (b *ByteSlice) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) { + return task.CopyOutBytes(addr, *b) +} + +// CopyOutN implements marshal.Marshallable.CopyOutN. +func (b *ByteSlice) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) { + return task.CopyOutBytes(addr, (*b)[:limit]) +} + +// WriteTo implements io.WriterTo.WriteTo. +func (b *ByteSlice) WriteTo(w io.Writer) (int64, error) { + n, err := w.Write(*b) + return int64(n), err +} + +var _ marshal.Marshallable = (*ByteSlice)(nil) + // Below, we define some convenience functions for marshalling primitive types // using the newtypes above, without requiring superfluous casts. diff --git a/tools/go_marshal/test/BUILD b/tools/go_marshal/test/BUILD index 2fbcc8a03..3d989823a 100644 --- a/tools/go_marshal/test/BUILD +++ b/tools/go_marshal/test/BUILD @@ -39,6 +39,6 @@ go_test( "//pkg/usermem", "//tools/go_marshal/analysis", "//tools/go_marshal/marshal", - "@com_github_google_go-cmp//cmp:go_default_library", + "@com_github_google_go_cmp//cmp:go_default_library", ], ) |