Analysing PHP Code

Analysing PHP Code Sebastian Bergmann November 18th 2009

Sebastian Bergmann  Co-Founder and Principal Consultant with thePHP.cc  Creator of PHPUnit  Involved in the PHP project since 2000

Code Analysis  Dynamic Code Analysis Analysis of software while executing it  Code Coverage  Profiling  Tracing  …  Static Code Analysis Analysis of software without executing it  Data-Flow Analysis  Software Metrics  Syntax Check  …

Dynamic Code Analysis Code Coverage  Xdebug1 provides raw code coverage information  xdebug_start_code_coverage()  xdebug_stop_code_coverage()  $data = xdebug_get_code_coverage()  PHPUnit2 leverages Xdebug to  generate Clover XML logfiles  generate HTML reports  php-code-coverage3 provides  a wrapper around Xdebug's low-level code coverage API  reusable functionality for code coverage analysis and reporting 1. http://xdebug.org/ 2. http://phpunit.de/ 3. http://github.com/sebastianbergmann/php-code-coverage

Dynamic Code Analysis Code Coverage with Xdebug <?php xdebug_start_code_coverage(); require_once 'function.php'; foo(); $coverage = xdebug_get_code_coverage(); print_r($coverage['/home/sb/function.php']); ?> Array function.php ( 1 <?php [2] => 1 2 function foo() 3 { [4] => 1 4 if (TRUE) { [5] => 1 5 $foo = TRUE; [6] => 1 6 } else { [10] => 1 7 $foo = FALSE; [12] => 1 8 } ) 9 10 return NULL; 11 }

Dynamic Code Analysis Code Coverage with Xdebug <?php xdebug_start_code_coverage(XDEBUG_CC_UNUSED); require_once 'function.php'; foo(); $coverage = xdebug_get_code_coverage(); print_r($coverage['/home/sb/function.php']); ?> Array function.php ( 1 <?php [2] => 1 2 function foo() 3 { [4] => 1 4 if (TRUE) { [5] => 1 5 $foo = TRUE; [6] => 1 6 } else { [7] => -1 7 $foo = FALSE; [10] => 1 8 } [11] => -1 9 [12] => 1 10 return NULL; 11 } )

Dynamic Code Analysis Code Coverage with Xdebug <?php xdebug_start_code_coverage(XDEBUG_CC_UNUSED | XDEBUG_CC_DEAD_CODE); require_once 'function.php'; foo(); $coverage = xdebug_get_code_coverage(); print_r($coverage['/home/sb/function.php']); ?> Array function.php ( 1 <?php [2] => 1 2 function foo() 3 { [4] => 1 4 if (TRUE) { [5] => 1 5 $foo = TRUE; [6] => 1 6 } else { [7] => -1 7 $foo = FALSE; [10] => 1 8 } [11] => -2 9 [12] => 1 10 return NULL; 11 } )

Dynamic Code Analysis Profiling  Xdebug1 writes profiling information in Cachegrind format  xdebug.profiler_enable=1  xdebug.profiler_enable_trigger=0  xdebug.profiler_output_dir=/tmp  xdebug.profiler_output_name=cachegrind.out.%p  xdebug.profiler_append=0 2  XHProf provides raw profiling information  xhprof_enable()  $data = xhprof_disable() 1. http://xdebug.org/ 2. http://pecl.php.net/package/xhprof

Dynamic Code Analysis Profiling with Xdebug sb@thinkpad phploc % php -d xdebug.profiler_enable=1 phploc.php --count-tests . phploc @package_version@ by Sebastian Bergmann. Directories: 5 Files: 9 Lines of Code (LOC): 1490 Cyclomatic Complexity / Lines of Code: 0.22 Executable Lines of Code (ELOC): 720 Comment Lines of Code (CLOC): 444 Non-Comment Lines of Code (NCLOC): 1046 . . .

Dynamic Code Analysis Analysing Xdebug Profiling Data with KCachegrind

Dynamic Code Analysis Profiling with XHProf <?php function.php require_once 'function.php'; <?php xhprof_enable(); function foo() { foo(); if (TRUE) { $foo = TRUE; $data = xhprof_disable(); } else { print_r($data); $foo = FALSE; ?> } Array ( return NULL; [main()==>foo] => Array } ( [ct] => 1 1 call from main() to foo() [wt] => 80 inclusive time in foo() when called from main() ) [main()==>xhprof_disable] => Array ( [ct] => 1 1 call from main() to xhprof_disable() [wt] => 4 inclusive time in xhprof_disable() when called from main() ) [main()] => Array fake symbol for main script entry ( [ct] => 1 [wt] => 140 inclusive time in main() ) )

Dynamic Code Analysis Profiling with XHProf <?php function.php require_once 'function.php'; <?php xhprof_enable(XHPROF_FLAGS_NO_BUILTINS); function foo() { foo(); if (TRUE) { $foo = TRUE; $data = xhprof_disable(); } else { print_r($data); $foo = FALSE; ?> } Array ( return NULL; [main()==>foo] => Array } ( [ct] => 1 1 call from main() to foo() [wt] => 80 inclusive time in foo() when called from main() ) [main()] => Array fake symbol for main script entry ( [ct] => 1 [wt] => 140 inclusive time in main() ) )

Dynamic Code Analysis Profiling with XHProf <?php function.php require_once 'function.php'; <?php xhprof_enable(XHPROF_FLAGS_CPU + XHPROF_FLAGS_MEMORY); function foo() { foo(); if (TRUE) { $foo = TRUE; $data = xhprof_disable(); } else { print_r($data); $foo = FALSE; ?> } Array ( return NULL; [main()==>foo] => Array } ( [ct] => 1 1 call from main() to foo() [wt] => 80 inclusive time in foo() when called from main() [cpu] => 0 cpu time in foo() when called from main() [mu] => 1480 change in PHP memory usage in bar() when called from foo() [pmu] => 0 change in PHP peak memory usage in bar() when called from foo() ) . . . )

Dynamic Code Analysis Analysing XHProf Profiling Data with XHProf UI <?php require_once 'function.php'; xhprof_enable(XHPROF_FLAGS_CPU + XHPROF_FLAGS_MEMORY); foo(); $data = xhprof_disable(); require_once 'xhprof_lib/utils/xhprof_lib.php'; require_once 'xhprof_lib/utils/xhprof_runs.php'; $run = new XHProfRuns_Default; $runId = $run->save_run($data, 'function'); print '<a href="http://localhost/xhprof_html/index.php?run=' . $runId . '&source=function">View profile</a>'; ?>  Analyse a single run: http://localhost/xhprof_html/index.php?source=<namespace>&run=<id>  Compare two runs: http://localhost/xhprof_html/index.php?source=<namespace>&run1=<id>&run2=<id>

Dynamic Code Analysis Tracing with Xdebug sb@thinkpad phploc % php -d xdebug.auto_trace=1 phploc.php --count-tests . phploc @package_version@ by Sebastian Bergmann. Directories: 5 Files: 9 Lines of Code (LOC): 1490 Cyclomatic Complexity / Lines of Code: 0.22 Executable Lines of Code (ELOC): 720 Comment Lines of Code (CLOC): 444 Non-Comment Lines of Code (NCLOC): 1046 . . .

Dynamic Code Analysis Tracing with Xdebug <?php function.php require_once 'function.php'; <?php xdebug_start_trace(); function foo() { foo(); if (TRUE) { $foo = TRUE; print file_get_contents(xdebug_get_tracefile_name()); xdebug_stop_trace(); } else { ?> $foo = FALSE; } return NULL; } TRACE START [2009-11-18 14:00:00] 0.0015 662408 -> foo() /home/sb/trace.php:6 0.0016 662528 -> xdebug_get_tracefile_name() /home/sb/trace.php:8 0.0016 662760 -> file_get_contents() /home/sb/trace.php:8

Static Code Analysis  Token-Level Analysis  ext/tokenizer1  PHP_TokenStream2  Syntax-Level Analysis  PHP_Reflection_AST3  ext/parse_tree4  Bytecode-Level Analysis  ext/bytekit5 1. http://php.net/tokenizer/ 2. http://github.com/sebastianbergmann/php-token-stream 3. Currently part of pdepend, http://pdepend.org/ 4. http://pecl.php.net/package/parse_tree 5. http://bytekit.org/

Static Code Analysis Compiling PHP Code, Phase 1: Lexical Analysis 1 <?php T_OPEN_TAG 2 if (TRUE) { T_IF T_WHITESPACE ( T_STRING ) T_WHITESPACE { T_WHITESPACE 3 print '*'; T_PRINT T_WHITESPACE T_CONSTANT_ENCAPSED_STRING ; T_WHITESPACE 4 } } T_WHITESPACE 5 ?> T_CLOSE_TAG

Static Code Analysis TokenLevel Analysis  ext/tokenizer1 provides raw token information  token_get_all($sourceCode)  token_name()  PHP_TokenStream2 provides a wrapper around the tokenizer extension's low-level API  All tokens represented through Token objects  SplDoublyLinkedList  SeekableIterator 1. http://php.net/tokenizer/ 2. http://github.com/sebastianbergmann/php-token-stream

Static Code Analysis TokenLevel Analysis with ext/tokenizer <?php function.php print_r(token_get_all(file_get_contents('function.php'))); ?> <?php function foo() Array ( { [0] => Array if (TRUE) { ( [0] => 368 T_OPEN_TAG $foo = TRUE; [1] => <?phpn text } else { [2] => 1 line number $foo = FALSE; ) } [1] => Array ( [0] => 334 T_FUNCTION return NULL; [1] => function } [2] => 2 ) [2] => Array ( [0] => 371 T_WHITESPACE [1] => [2] => 2 ) [3] => Array ( [0] => 307 T_STRING [1] => foo [2] => 2 ) [4] => ( . .

Static Code Analysis TokenLevel Analysis with PHP_TokenStream <?php function.php require_once 'PHP/Token/Stream.php'; <?php function foo() print_r(new PHP_Token_Stream('function.php')); { ?> if (TRUE) { PHP_Token_Stream Object $foo = TRUE; ( } else { [flags:SplDoublyLinkedList:private] => 0 $foo = FALSE; [dllist:SplDoublyLinkedList:private] => Array } ( [0] => PHP_Token_OPEN_TAG Object ( return NULL; [id:protected] => 368 } [text:protected] => <?phpn [line:protected] => 1 ) . . [4] => PHP_Token_OPEN_BRACKET Object ( [id:protected] => 501 [text:protected] => ( [line:protected] => 2 ) . .

Static Code Analysis Compiling PHP Code, Phase 2: Syntax Analysis

Static Code Analysis SyntaxLevel Analysis 1  PHP_Reflection_AST  provides an API to traverse the object- oriented structure of a PHP project 2  ext/parse_tree  provides an XML representation of the AST  comes with an XSLT stylesheet that emits PHP 1. Currently part of pdepend, http://pdepend.org/ 2. http://pecl.php.net/package/parse_tree

Static Code Analysis SyntaxLevel Analysis with PHP_Reflection_AST <?php source.php require_one 'PHP/Reflection.php'; <?php class Foo $reflection = new PHP_Reflection; { $packages = $reflection->parse('source.php'); public function bar() { foreach ($packages as $package) { print 'baz'; var_dump($package->getName()); } } foreach ($package->getClasses() as $class) { var_dump($class->getName()); foreach ($class->getMethods() as $method) { var_dump($method->getName()); } } } ?> string(8) "+unknown" string(3) "Foo" string(3) "bar"

Static Code Analysis SyntaxLevel Analysis with ext/parse_tree <?php print parse_tree_from_file(__FILE__); ?> <?xml version="1.0" encoding="ISO-8859-1" ?> <php:start xmlns:php="http://php.net/xsl"> <php:statement> <php:unticked_statement> <php:expr> <php:expr_without_variable> <php:T_PRINT>print</php:T_PRINT> <php:expr> <php:r_variable> <php:variable> <php:base_variable_with_function_calls> <php:function_call> <php:T_STRING>parse_tree_from_file</php:T_STRING> <php:CHAR40>(</php:CHAR40> <php:function_call_parameter_list> <php:non_empty_function_call_parameter_list> <php:expr_without_variable> <php:scalar> <php:common_scalar> <php:T_FILE>__FILE__</php:T_FILE> </php:common_scalar> </php:scalar> </php:expr_without_variable> </php:non_empty_function_call_parameter_list> </php:function_call_parameter_list> <php:CHAR41>)</php:CHAR41> </php:function_call> </php:base_variable_with_function_calls> </php:variable> </php:r_variable> </php:expr> </php:expr_without_variable> </php:expr> <php:CHAR59>;</php:CHAR59> </php:unticked_statement> </php:statement> </php:start>

Static Code Analysis Compiling PHP Code, Phase 3: Bytecode Generation 1 <?php 2 if (TRUE) { 3 print '*'; 4 } 5 ?> sb@thinkpad ~ % bytekit if.php bytekit-cli 1.0.0 by Sebastian Bergmann. Filename: /home/sb/if.php Function: main Number of oplines: 8 line # opcode result operands ----------------------------------------------------------------------------- 2 0 EXT_STMT 1 JMPZ true, ->6 3 2 EXT_STMT 3 PRINT ~0 '*' 4 FREE ~0 4 5 JMP ->6 6 6 EXT_STMT 7 RETURN 1

Static Code Analysis BytecodeLevel Analysis with ext/bytekit <?php $bytecode = bytekit_disassemble_file('if.php'); ?> 'functions' => array( 'main' => array( 'code' => ..., // disassembled code 'cfg' => ..., // code flow graph 'entries' => ..., // incoming edges 'exits' => ..., // outgoing edges 'bb' => ..., // basic blocks 'next_t' => ..., // true edges 'next_f' => ..., // false edges 'exception' => ..., // exception edges 'raw' => ... // raw op_array data ) ) Further reading: http://www.bytekit.org/download/IPC09-Bytekit.pdf

The End Thank you for your interest! These slides will be posted on http://slideshare.net/sebastian_bergmann

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Analysing PHP Code

by Sebastian Bergmann on Nov 18, 2009

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Analysing PHP Code — Presentation Transcript