Callstack collection and dump & positions for invokable

.php-cs-fixer.php

@@ -18,10 +18,12 @@
 ];
 
 config->setRules(rules);
-config->setFinder(PhpCsFixer\Finder::create()
-    ->in(__DIR__ . '/bin')
-    ->in(__DIR__ . '/src')
-    ->in(__DIR__ . '/tests')
+config->setRiskyAllowed(true);
+config->setFinder(
+    PhpCsFixer\Finder::create()
+        ->in(__DIR__ . '/bin')
+        ->in(__DIR__ . '/src')
+        ->in(__DIR__ . '/tests'),
 );
 
 return config;

README.md

@@ -42,7 +42,7 @@ php main.php
 
 ## WIP
 
-This is a toy project, currently work-in-progress.
+This is a toy project, not intended for production use.
 
 To see what is already implemented, refer to [tests](tests/Functional/files/).
 
@@ -61,3 +61,7 @@ make test
 ```
 
 run `make help` for more commands.
+
+## Differences from the Go compiler
+
+- No support for real goroutines, go statements run sequentially

bin/go-php

@@ -4,12 +4,15 @@
 declare(strict_types=1);
 
 use GoPhp\EnvVarSet;
-use GoPhp\ErrorHandler\OutputToStream;
+use GoPhp\ErrorHandler\StreamWriter;
+use GoPhp\ExitCode;
 use GoPhp\Interpreter;
 use GoPhp\Stream\ResourceOutputStream;
 
 use const GoPhp\VERSION;
 
+use function GoPhp\Debug\dump_call_stack;
+
 const AUTOLOAD_PATHS = [
     __DIR__ . '/../vendor/autoload.php',
     __DIR__ . '/../../../autoload.php',
@@ -55,6 +58,7 @@ function print_help(): void
         -e, --eval          Evaluate given code
         --goroot            Set GOROOT environment variable
         --gopath            Set GOPATH environment variable
+        --dump-stack-trace  Dump stack trace on error
 
     HELP, VERSION));
 }
@@ -71,6 +75,7 @@ enum Flag: string
     case Eval = 'eval';
     case Goroot = 'goroot';
     case Gopath = 'gopath';
+    case DumpStackTrace = 'dump-stack-trace';
 
     private const array FLAGS_WITH_VALUE = [
         self::Goroot,
@@ -81,6 +86,7 @@ enum Flag: string
         self::Help,
         self::Version,
         self::Eval,
+        self::DumpStackTrace,
     ];
 
     /**
@@ -139,6 +145,7 @@ function main(array $argv): never
     $gopath = EnvVarSet::DEFAULT_GOPATH;
     $eval = false;
     $script = null;
+    $dumpTrace = false;
 
     foreach ($argv as $arg) {
         if ($eval) {
@@ -166,6 +173,9 @@ function main(array $argv): never
             case Flag::Eval:
                 $eval = true;
                 break;
+            case Flag::DumpStackTrace:
+                $dumpTrace = true;
+                break;
             default:
                 $file = $arg;
                 break 2;
@@ -177,25 +187,30 @@ function main(array $argv): never
         exit(0);
     }
 
-    $src = $script !== null
-        ? $script
-        : file_get_contents($file);
-
     $stderr = new ResourceOutputStream(STDERR);
-    $errorHandler = new OutputToStream($stderr);
+    $errorHandler = new StreamWriter($stderr);
 
     $runtime = Interpreter::create(
-        source: $src,
+        source: $script !== null ? $script : null,
         errorHandler: $errorHandler,
         envVars: new EnvVarSet(
             goroot: $goroot,
             gopath: $gopath,
         ),
+        filename: $file,
         toplevel: $script !== null,
+        debug: $dumpTrace,
     );
 
     $result = $runtime->run();
 
+    if ($dumpTrace && $result->exitCode === ExitCode::Failure) {
+        $callStack = $result->debugger?->getCallStack();
+
+        fwrite(STDERR, "\n");
+        dump_call_stack($callStack);
+    }
+
     exit($result->exitCode->value);
 }
 

composer.json

@@ -14,7 +14,7 @@
         "tuqqu/go-parser": "^0.5.1"
     },
     "require-dev": {
-        "symfony/var-dumper": "^6",
+        "symfony/var-dumper": "^7",
         "friendsofphp/php-cs-fixer": "^3.48",
         "phpunit/phpunit": "^10.5",
         "vimeo/psalm": "^5.20"
@@ -29,6 +29,7 @@
         "files": [
             "src/asserts.php",
             "src/utils.php",
+            "src/Debug/utils.php",
             "src/GoValue/utils.php"
         ]
     },

examples/helloworld/main.php

@@ -22,4 +22,4 @@
 $result = $interp->run();
 
 print "Output:\n$stdout\n";
-print "Exit code: $result->exitCode->value\n";
+print "Exit code: {$result->exitCode->value}\n";

examples/sorting/main.php

@@ -22,4 +22,4 @@
 $result = $interp->run();
 
 print "Output:\n$stdout\n";
-print "Exit code: $result->exitCode->value\n";
+print "Exit code: {$result->exitCode->value}\n";

src/Builtin/BuiltinFunc/Recover.php

@@ -24,10 +24,10 @@ public function __construct(
     public function __invoke(Argv $argv): InterfaceValue
     {
         assert_argc($this, $argv, 0);
+        $lastPanic = $this->panicPointer->pointsTo();
 
-        if ($this->panicPointer->panic !== null) {
-            $lastPanic = $this->panicPointer->panic;
-            $this->panicPointer->panic = null;
+        if ($lastPanic !== null) {
+            $this->panicPointer->clear();
 
             return new InterfaceValue($lastPanic->panicValue);
         }

src/Debug/CallStack.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GoPhp\Debug;
+
+use function array_pop;
+use function array_reverse;
+use function array_shift;
+use function count;
+
+final class CallStack
+{
+    /**
+     * @var list<CallTrace>
+     */
+    private array $callTraces = [];
+
+    public function __construct(
+        private readonly int $limit,
+    ) {}
+
+    public function add(CallTrace $callTrace): void
+    {
+        if (count($this->callTraces) > $this->limit) {
+            array_shift($this->callTraces);
+        }
+
+        $this->callTraces[] = $callTrace;
+    }
+
+    public function pop(): void
+    {
+        array_pop($this->callTraces);
+    }
+
+    /**
+     * @return list<CallTrace>
+     */
+    public function getCallTraces(): array
+    {
+        return array_reverse($this->callTraces);
+    }
+
+    public function count(): int
+    {
+        return count($this->callTraces);
+    }
+}

src/Debug/CallStackCollectorDebugger.php

@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GoPhp\Debug;
+
+use GoPhp\Error\InternalError;
+use GoPhp\GoValue\AddressableValue;
+use GoPhp\GoValue\BuiltinFuncValue;
+use GoPhp\InvokableCall;
+
+final class CallStackCollectorDebugger implements Debugger
+{
+    public const int DEFAULT_STACK_TRACE_DEPTH = 128;
+
+    private readonly CallStack $callStack;
+
+    public function __construct(int $maxTraceDepth = self::DEFAULT_STACK_TRACE_DEPTH)
+    {
+        $this->callStack = new CallStack($maxTraceDepth);
+    }
+
+    public function addStackTrace(InvokableCall $call): void
+    {
+        $name = match (true) {
+            $call->func instanceof AddressableValue => $call->func->getQualifiedName(),
+            $call->func instanceof BuiltinFuncValue => $call->func->getName(),
+            default => throw new InternalError(sprintf('unknown call stack value %s', $call->func::class)),
+        };
+
+        $this->callStack->add(new CallTrace($name, $call->getPosition()));
+    }
+
+    public function releaseLastStackTrace(): void
+    {
+        $this->callStack->pop();
+    }
+
+    public function getCallStack(): CallStack
+    {
+        return $this->callStack;
+    }
+}

src/Debug/CallTrace.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GoPhp\Debug;
+
+use GoParser\Lexer\Position;
+
+final class CallTrace
+{
+    public function __construct(
+        public readonly string $name,
+        public readonly ?Position $position,
+    ) {}
+}

src/Debug/Debugger.php

@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GoPhp\Debug;
+
+use GoPhp\InvokableCall;
+
+interface Debugger
+{
+    public function addStackTrace(InvokableCall $call): void;
+
+    public function releaseLastStackTrace(): void;
+
+    public function getCallStack(): CallStack;
+}

src/Debug/utils.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GoPhp\Debug;
+
+use GoParser\Lexer\Position;
+
+use function realpath;
+use function sprintf;
+
+use const STDERR;
+
+/**
+ * Dumps the call stack to STDERR.
+ */
+function dump_call_stack(CallStack $callStack): void
+{
+    $positionDumper = fn(?Position $position): string => $position === null
+        ? 'unknown'
+        : sprintf(
+            "%s:%d:%d",
+            $position->filename === null
+                ? ''
+                : realpath($position->filename),
+            $position->line,
+            $position->offset,
+        );
+
+    $callTraces = $callStack->getCallTraces();
+    $length = $callStack->count();
+
+    for ($i = 0; $i < $length; $i++) {
+        if ($i === 0) {
+            continue;
+        }
+
+        fwrite(STDERR, sprintf(
+            "%s(...)\n\t%s\n",
+            $callTraces[$i]->name,
+            $positionDumper($callTraces[$i - 1]->position),
+        ));
+    }
+}