diff options
Diffstat (limited to 'vendor/github.com/tetratelabs/wazero/internal/wasmdebug/debug.go')
-rw-r--r-- | vendor/github.com/tetratelabs/wazero/internal/wasmdebug/debug.go | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/vendor/github.com/tetratelabs/wazero/internal/wasmdebug/debug.go b/vendor/github.com/tetratelabs/wazero/internal/wasmdebug/debug.go new file mode 100644 index 000000000..ff0e0cccc --- /dev/null +++ b/vendor/github.com/tetratelabs/wazero/internal/wasmdebug/debug.go @@ -0,0 +1,170 @@ +// Package wasmdebug contains utilities used to give consistent search keys between stack traces and error messages. +// Note: This is named wasmdebug to avoid conflicts with the normal go module. +// Note: This only imports "api" as importing "wasm" would create a cyclic dependency. +package wasmdebug + +import ( + "fmt" + "runtime" + "runtime/debug" + "strconv" + "strings" + + "github.com/tetratelabs/wazero/api" + "github.com/tetratelabs/wazero/internal/wasmruntime" + "github.com/tetratelabs/wazero/sys" +) + +// FuncName returns the naming convention of "moduleName.funcName". +// +// - moduleName is the possibly empty name the module was instantiated with. +// - funcName is the name in the Custom Name section. +// - funcIdx is the position in the function index, prefixed with +// imported functions. +// +// Note: "moduleName.$funcIdx" is used when the funcName is empty, as commonly +// the case in TinyGo. +func FuncName(moduleName, funcName string, funcIdx uint32) string { + var ret strings.Builder + + // Start module.function + ret.WriteString(moduleName) + ret.WriteByte('.') + if funcName == "" { + ret.WriteByte('$') + ret.WriteString(strconv.Itoa(int(funcIdx))) + } else { + ret.WriteString(funcName) + } + + return ret.String() +} + +// signature returns a formatted signature similar to how it is defined in Go. +// +// * paramTypes should be from wasm.FunctionType +// * resultTypes should be from wasm.FunctionType +// TODO: add paramNames +func signature(funcName string, paramTypes []api.ValueType, resultTypes []api.ValueType) string { + var ret strings.Builder + ret.WriteString(funcName) + + // Start params + ret.WriteByte('(') + paramCount := len(paramTypes) + switch paramCount { + case 0: + case 1: + ret.WriteString(api.ValueTypeName(paramTypes[0])) + default: + ret.WriteString(api.ValueTypeName(paramTypes[0])) + for _, vt := range paramTypes[1:] { + ret.WriteByte(',') + ret.WriteString(api.ValueTypeName(vt)) + } + } + ret.WriteByte(')') + + // Start results + resultCount := len(resultTypes) + switch resultCount { + case 0: + case 1: + ret.WriteByte(' ') + ret.WriteString(api.ValueTypeName(resultTypes[0])) + default: // As this is used for errors, don't panic if there are multiple returns, even if that's invalid! + ret.WriteByte(' ') + ret.WriteByte('(') + ret.WriteString(api.ValueTypeName(resultTypes[0])) + for _, vt := range resultTypes[1:] { + ret.WriteByte(',') + ret.WriteString(api.ValueTypeName(vt)) + } + ret.WriteByte(')') + } + + return ret.String() +} + +// ErrorBuilder helps build consistent errors, particularly adding a WASM stack trace. +// +// AddFrame should be called beginning at the frame that panicked until no more frames exist. Once done, call Format. +type ErrorBuilder interface { + // AddFrame adds the next frame. + // + // * funcName should be from FuncName + // * paramTypes should be from wasm.FunctionType + // * resultTypes should be from wasm.FunctionType + // * sources is the source code information for this frame and can be empty. + // + // Note: paramTypes and resultTypes are present because signature misunderstanding, mismatch or overflow are common. + AddFrame(funcName string, paramTypes, resultTypes []api.ValueType, sources []string) + + // FromRecovered returns an error with the wasm stack trace appended to it. + FromRecovered(recovered interface{}) error +} + +func NewErrorBuilder() ErrorBuilder { + return &stackTrace{} +} + +type stackTrace struct { + // frameCount is the number of stack frame currently pushed into lines. + frameCount int + // lines contains the stack trace and possibly the inlined source code information. + lines []string +} + +// GoRuntimeErrorTracePrefix is the prefix coming before the Go runtime stack trace included in the face of runtime.Error. +// This is exported for testing purpose. +const GoRuntimeErrorTracePrefix = "Go runtime stack trace:" + +func (s *stackTrace) FromRecovered(recovered interface{}) error { + if false { + debug.PrintStack() + } + + if exitErr, ok := recovered.(*sys.ExitError); ok { // Don't wrap an exit error! + return exitErr + } + + stack := strings.Join(s.lines, "\n\t") + + // If the error was internal, don't mention it was recovered. + if wasmErr, ok := recovered.(*wasmruntime.Error); ok { + return fmt.Errorf("wasm error: %w\nwasm stack trace:\n\t%s", wasmErr, stack) + } + + // If we have a runtime.Error, something severe happened which should include the stack trace. This could be + // a nil pointer from wazero or a user-defined function from HostModuleBuilder. + if runtimeErr, ok := recovered.(runtime.Error); ok { + return fmt.Errorf("%w (recovered by wazero)\nwasm stack trace:\n\t%s\n\n%s\n%s", + runtimeErr, stack, GoRuntimeErrorTracePrefix, debug.Stack()) + } + + // At this point we expect the error was from a function defined by HostModuleBuilder that intentionally called panic. + if runtimeErr, ok := recovered.(error); ok { // e.g. panic(errors.New("whoops")) + return fmt.Errorf("%w (recovered by wazero)\nwasm stack trace:\n\t%s", runtimeErr, stack) + } else { // e.g. panic("whoops") + return fmt.Errorf("%v (recovered by wazero)\nwasm stack trace:\n\t%s", recovered, stack) + } +} + +// MaxFrames is the maximum number of frames to include in the stack trace. +const MaxFrames = 30 + +// AddFrame implements ErrorBuilder.AddFrame +func (s *stackTrace) AddFrame(funcName string, paramTypes, resultTypes []api.ValueType, sources []string) { + if s.frameCount == MaxFrames { + return + } + s.frameCount++ + sig := signature(funcName, paramTypes, resultTypes) + s.lines = append(s.lines, sig) + for _, source := range sources { + s.lines = append(s.lines, "\t"+source) + } + if s.frameCount == MaxFrames { + s.lines = append(s.lines, "... maybe followed by omitted frames") + } +} |