Files
tinygo/compileopts/options.go
Jake Bailey 89d9e33bca interp: bail out of loops that iterate too many times (#5395)
* interp: bail out of loops that iterate too many times

The existing loop guard (errLoopUnrolled) only fires when a loop body
emits runtime instructions. Loops that are fully evaluable at compile
time, such as inserting thousands of entries into a map, were not
caught and could hang the compiler.

Add a per-basic-block iteration counter that triggers a recoverable
error (errLoopTooLong) when any block is entered more than 1000 times
in a single function call. This defers the init function to runtime,
which is the same behavior as other interp bailouts.

Profiling showed that 83% of CPU time was spent in GC, caused by
allocation pressure from the interp memory cloning on each map
mutation. The iteration limit avoids this entirely by bailing out
before the quadratic cost becomes significant.

Performance on the reproducer from #2090 (map init with strconv.Itoa):

    entries  before       after
    5,000    7.4s         2.1s
    10,000   17.5s        2.1s
    20,000   48.0s        2.8s
    65,536   >180s (OOM)  3.2s

* Add -interp-loop-limit
2026-05-17 20:42:27 +02:00

138 lines
4.5 KiB
Go

package compileopts
import (
"fmt"
"regexp"
"strings"
"time"
)
var (
validBuildModeOptions = []string{"default", "c-shared", "wasi-legacy"}
validGCOptions = []string{"none", "leaking", "conservative", "custom", "precise", "boehm"}
validSchedulerOptions = []string{"none", "tasks", "asyncify", "threads", "cores"}
validSerialOptions = []string{"none", "uart", "usb", "rtt"}
validPrintSizeOptions = []string{"none", "short", "full", "html"}
validPanicStrategyOptions = []string{"print", "trap"}
validOptOptions = []string{"none", "0", "1", "2", "s", "z"}
)
// Options contains extra options to give to the compiler. These options are
// usually passed from the command line, but can also be passed in environment
// variables for example.
type Options struct {
GOOS string // environment variable
GOARCH string // environment variable
GOARM string // environment variable (only used with GOARCH=arm)
GOMIPS string // environment variable (only used with GOARCH=mips and GOARCH=mipsle)
Directory string // working dir, leave it unset to use the current working dir
Target string
BuildMode string // -buildmode flag
Opt string
GC string
PanicStrategy string
Scheduler string
StackSize uint64 // goroutine stack size (if none could be automatically determined)
Serial string
Work bool // -work flag to print temporary build directory
InterpTimeout time.Duration
InterpMaxLoopIterations int
PrintIR bool
DumpSSA bool
VerifyIR bool
SkipDWARF bool
PrintCommands func(cmd string, args ...string) `json:"-"`
Semaphore chan struct{} `json:"-"` // -p flag controls cap
Debug bool
Nobounds bool
PrintSizes string
PrintAllocs *regexp.Regexp // regexp string
PrintStacks bool
Tags []string
GlobalValues map[string]map[string]string // map[pkgpath]map[varname]value
TestConfig TestConfig
Programmer string
OpenOCDCommands []string
LLVMFeatures string
Monitor bool
BaudRate int
Timeout time.Duration
WITPackage string // pass through to wasm-tools component embed invocation
WITWorld string // pass through to wasm-tools component embed -w option
ExtLDFlags []string
GoCompatibility bool // enable to check for Go version compatibility
}
// Verify performs a validation on the given options, raising an error if options are not valid.
func (o *Options) Verify() error {
if o.BuildMode != "" {
valid := isInArray(validBuildModeOptions, o.BuildMode)
if !valid {
return fmt.Errorf(`invalid buildmode option '%s': valid values are %s`,
o.BuildMode,
strings.Join(validBuildModeOptions, ", "))
}
}
if o.GC != "" {
valid := isInArray(validGCOptions, o.GC)
if !valid {
return fmt.Errorf(`invalid gc option '%s': valid values are %s`,
o.GC,
strings.Join(validGCOptions, ", "))
}
}
if o.Scheduler != "" {
valid := isInArray(validSchedulerOptions, o.Scheduler)
if !valid {
return fmt.Errorf(`invalid scheduler option '%s': valid values are %s`,
o.Scheduler,
strings.Join(validSchedulerOptions, ", "))
}
}
if o.Serial != "" {
valid := isInArray(validSerialOptions, o.Serial)
if !valid {
return fmt.Errorf(`invalid serial option '%s': valid values are %s`,
o.Serial,
strings.Join(validSerialOptions, ", "))
}
}
if o.PrintSizes != "" {
valid := isInArray(validPrintSizeOptions, o.PrintSizes)
if !valid {
return fmt.Errorf(`invalid size option '%s': valid values are %s`,
o.PrintSizes,
strings.Join(validPrintSizeOptions, ", "))
}
}
if o.PanicStrategy != "" {
valid := isInArray(validPanicStrategyOptions, o.PanicStrategy)
if !valid {
return fmt.Errorf(`invalid panic option '%s': valid values are %s`,
o.PanicStrategy,
strings.Join(validPanicStrategyOptions, ", "))
}
}
if o.Opt != "" {
if !isInArray(validOptOptions, o.Opt) {
return fmt.Errorf("invalid -opt=%s: valid values are %s", o.Opt, strings.Join(validOptOptions, ", "))
}
}
return nil
}
func isInArray(arr []string, item string) bool {
for _, i := range arr {
if i == item {
return true
}
}
return false
}