[PPT] - DebugAllYourCode: PortableMixedEnvironmentDebugging PowerPoint Presentation

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Debug All Your Code:   Portable Mixed‐Environment Debugging 

Byeongcheol Lee   Mar:n Hirzel  Robert Grimm  Kathryn McKinley 

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OOPSLA 2009

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

1. Leverage legacy code and exis:ng libraries.  2. Match language features to a task. 

FFI Mixed-Language X Language Y Language

Programmers build systems in mul:ple languages. 

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Portable mixed‐environment debugging 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

JNI Mixed-Environment Managed Java Native C/C++

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Portable mixed‐environment debugging 

1. Leverage legacy code and exis:ng libraries.  2. Match language features to a task. 

Programmers build systems in mul:ple languages. 

Mixed-Language

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

JNI Managed Java Native C/C++

Bugs appear in all your code!

4

The problem 

Mixed-Environment

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

JNI Managed Java Native C/C++

The problem with single‐environment debugging 

Eclipse JDT

0 

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Mixed-Environment

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

JNI Managed Java Native C/C++

The problem with single‐environment debugging 

0 

Eclipse CDT

6

Mixed-Environment

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Portable mixed-environment debugging

JNI Managed Java Native C/C++

7

Our goal 

Mixed-Environment

SLIDE 8

B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Our contribu:on and results  Composi:on 

1. Add an intermediate agent.  2. AOach single‐environment debuggers.  3. Dispatch debuggers dynamically. 

Blink results 

1. Simple: Add 10 K SLOC of new code.  2. Portable: Support Linux, Windows, Hotspot, J9,  GCC, MicrosoW C++.  3. Powerful: Catch FFI bugs. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Problem: GDB does not work at a Java breakpoint.  

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JNI Managed Java Native C/C++ JDB GDB

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Problem: GDB does not work at a Java breakpoint.  

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JNI Managed Java Native C/C++ JDB GDB Naïve composition How can I print a C variable at a  Java breakpoint?  Unfortunately, GDB does not  work at the Java breakpoint. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Our solu:on: the intermediate agent switches debugger context. 

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JNI Managed Java Native C/C++ JDB GDB Blink controller We will wake up GDB at a Java  breakpoint ‐ Switching  debugger context. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Our solu:on: switch debugger context from Java to C. 

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JDB  J‐Agent  C‐Agent  j2c(){cbreak();  void cbreak(){  eval j2c() breakpoint hit GDB

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Our solu:on: switch debugger context from Java to C. 

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JDB  J‐Agent  C‐Agent  j2c(){cbreak();  void cbreak(){  eval j2c() breakpoint hit GDB print c_var

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Our solu:on: switch debugger context from Java to C. 

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JDB  J‐Agent  C‐Agent  j2c(){cbreak();  void cbreak(){  eval j2c() return;}  return;}  j2c() completed breakpoint hit continue GDB print c_var

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Problem: GDB does not understand JNI calling conven:ons. 

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JNI Managed Java Native C/C++ JDB GDB How did the program reach the  current breakpoint?  How can I tell you the calling  context?  Unfortunately, GDB does not  understand JNI transiNons.  Naïve composition

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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jping(i)  cpong(j) 

Problem: GDB does not understand JNI calling conven:ons. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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j2j_call j2c_call main  jping(3)  cpong(2)  Problem: GDB does not understand JNI calling conven:ons.  main  jping(3)  cpong(2)  JDB stack GDB stack

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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j2j_call j2c_call c2j_call main  jping(3)  cpong(2)  jping(1)  Problem: GDB does not understand JNI calling conven:ons.  main  jping(3)  jping(1)  cpong(2)  JDB stack GDB stack GDB does not  understand JNI  calling  convenNon. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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j2j_call j2c_call c2j_call j2c_call main  jping(3)  cpong(2)  jping(1)  cpong(0)  Problem: GDB does not understand JNI calling conven:ons.  main  jping(3)  jping(1)  cpong(0)  cpong(2)  JDB stack GDB stack GDB does not  understand JNI  calling  convenNon. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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j2j_call j2c_call c2j_call j2c_call main  jping(3)  jping(1)  cpong(0)  cpong(2)  main  jping(3)  cpong(2)  jping(1)  cpong(0)  JDB stack GDB stack with the agent

Our solu:on: translate JNI transi:ons into C transi:ons. 

The agent  translates JNI  calls into C calls  – transiNon  interposiNon. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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j2j_call j2c_call c2j_call j2c_call main  jping(3)  jping(1)  cpong(0)  cpong(2)  main  jping(3)  cpong(2)  jping(1)  cpong(0)  JDB GDB with the agent

Our solu:on: compose a calling context. 

main  jping(3)  jping(1)  Blink cpong(0)  cpong(2) 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Our solu:on: controller and intermediate agent 

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JNI Managed Java Native C/C++ JDB GDB Controller Intermediate  agent 

SLIDE 23

B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

I. Problem  II. Debugger composi:on 

A. Switching debugger context  B. Interposing transi:ons 

III. Advanced features

A. Evalua:ng Jeannie mixed‐environment expressions  B. Detec:ng FFI bugs 

IV. Evalua:on

23

Outline 

SLIDE 24

B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

JNI Mixed-Environment Managed Java Native C/C++

Debugging boundary code 

24

What do I need to debug boundary  code? 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

JNI Mixed-Environment Managed Java Native C/C++

Advanced features to debug boundary code 

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2. Detec:ng FFI bugs  1. Evalua:ng Jeannie Expressions 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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jstring name;

Problem: you can not de‐reference opaque pointers in C. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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jstring name;

print *name 

The name is an 

paque C pointer.

Problem: you can not de‐reference opaque pointers in C. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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“smiley” 

jstring name;

print *name  print `name 

The name is an 

paque C pointer.

The Jeannie  backNck gives me  eyes to see the  Java world. 

Our solu:on: use Jeannie expression 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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“smiley” 

jstring name;

print *name  print `name 

The name is an 

paque C pointer.

How can I evaluate  the Jeannie  expression? 

Our solu:on: use Jeannie expression. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Build abstract syntax tree 

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print

`

name

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Evaluate AST in BoOom‐up order. 

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JDB  Agent  GDB $vc1 = name

print

`

name

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Evaluate AST in BoOom‐up order. 

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JDB  Agent  GDB $vc1 = name $vj2 = $vc1

print

`

name

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Evaluate AST in BoOom‐up order. 

33

print

`

name

JDB  Agent  GDB $vc1 = name $vj2 = $vc1 Print $vj2

“smiley” 

SLIDE 34

B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

JNI Managed Java Native C/C++

Advanced features 

34

B. Detec:ng FFI bugs  A. Evalua:ng Jeannie Expressions 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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(*env)‐>GetStringUTFChars(env, NULL); 

C code 

Problem: you may misuse foreign func:on interface. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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(*env)‐>GetStringUTFChars(env, NULL); 

C code  The NULL is invalid. The java-gnome bug 576107 crashes the J9 JVM.

Problem: you may misuse foreign func:on interface. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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(*env)‐>GetStringUTFChars(env, NULL); 

c2j_wrap_GetStringUTFChars(env, cstr) { 

C code  Agent  GDB The NULL is invalid. The java-gnome bug 576107 crashes the IBM J9 SR5.

Our solu:on: detect FFI bugs 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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(*env)‐>GetStringUTFChars(env, NULL); 

c2j_wrap_GetStringUTFChars(env, cstr) {    if  (cstr == NULL) {cbreak();}  

C code  Agent  GDB The NULL is invalid. The java-gnome bug 576107 crashes the IBM J9 SR5.

Our solu:on: detect FFI bugs. 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

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(*env)‐>GetStringUTFChars(env, NULL); 

c2j_wrap_GetStringUTFChars(env, cstr) {    if  (cstr == NULL) {cbreak();}   void cbreak() { 

C code  Agent  GDB The NULL is invalid. The java-gnome bug 576107 crashes the IBM J9 SR5. The agent immediately reports the bug.

Our solu:on: detect FFI bugs. 

SLIDE 40

B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

I. Problem  II. Debugger composi:on 

A. Switching debugger context  B. Interposing transi:ons 

III. Advanced features

A. Evalua:ng Jeannie mixed‐environment expressions  B. Detec:ng FFI bugs 

IV. Evalua:on

40

Outline 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is simple. 

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515K source lines of code in total JDB  17%  GDB  81%  Agent   1%  Controller  1% 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is portable. 

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Source lines of code Platforms IA32/Linux/ Hotspot 4,575 8,840 Agent Controller

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is portable. 

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Source lines of code Platforms IA32/Linux/ Hotspot J9 4,575 8,840 Agent Controller

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is portable. 

44

Source lines of code Platforms IA32/Linux/ Hotspot J9 Cygwin 4,575 8,840 Agent Controller

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is portable. 

45

Source lines of code Platforms IA32/Linux/ Hotspot J9 Cygwin Windows 4,575 8,840 9,481 Agent Controller

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is powerful. 

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The bug 576107 in java-gnome 4.0.10

Hotspot VM 1.6.0_10  J9 VM SR5  Produc:on run  running  crash 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is powerful. 

47

The bug 576107 in java-gnome 4.0.10

Hotspot VM 1.6.0_10  J9 VM SR5  Produc:on run  running  crash  Run:me  checking  (‐Xcheck:jni)  warning  warning 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is powerful. 

48

The bug 576107 in java-gnome 4.0.10

Hotspot VM 1.6.0_10  J9 VM SR5  Produc:on run  running  crash  Run:me  checking  (‐Xcheck:jni)  warning  warning  jdb  running  crash  gdb  running  fault 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Composi:on is powerful. 

49

The bug 576107 in java-gnome 4.0.10

Hotspot VM 1.6.0_10  J9 VM SR5  Produc:on run  running  crash  Run:me  checking  (‐Xcheck:jni)  warning  warning  jdb  running  crash  gdb  running  fault 

Blink  breakpoint  breakpoint 

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Related work 

Mixed‐environment debuggers

– Intel XDI for Harmony JVM  – SUN dbx  – MicrosoW .NET debuggers 

Advance debugging features

– Sta:c analyses 

BEAM [Kondoh & Onodera ’08] 
J‐Saffire [Furr & Foster ’06] 
ILEA [Tan & MorriseO ‘07]

– Language designs 

Jeannie [Hirzel & Grimm ‘07] 
SafeJNI [Tan et al. ‘06]

– Wrapper generators 

Automa:c binding generator [Ravitch ‘09] 
SWIG [Beazley ‘96]

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Summary 

Portable mixed‐environment debugging 
Composi:on with an intermediate agent 
1. Switching debugger context 
2. Interposing transi:ons 
Results 
1. Simple 
2. Portable 
3. Powerful

51

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B. Lee, M. Hirzel, R. Grimm, and K. S. McKinley

Thank you 

52

Debug All Your Code: Portable Mixed‐Environment Debugging

Byeongcheol Lee Mar:n Hirzel Robert Grimm Kathryn McKinley

OOPSLA 2009

1. Leverage legacy code and exis:ng libraries. 2. Match language features to a task.

FFI Mixed-Language X Language Y Language

Programmers build systems in mul:ple languages.

Portable mixed‐environment debugging

JNI Mixed-Environment Managed Java Native C/C++

Portable mixed‐environment debugging

1. Leverage legacy code and exis:ng libraries. 2. Match language features to a task.

Programmers build systems in mul:ple languages.

Mixed-Language

JNI Managed Java Native C/C++

Bugs appear in all your code!

The problem

Mixed-Environment

JNI Managed Java Native C/C++

The problem with single‐environment debugging

Eclipse JDT

0

Mixed-Environment

JNI Managed Java Native C/C++

The problem with single‐environment debugging

0

Eclipse CDT

Mixed-Environment

Portable mixed-environment debugging

JNI Managed Java Native C/C++

Our goal

Mixed-Environment

Our contribu:on and results Composi:on

1. Add an intermediate agent. 2. AOach single‐environment debuggers. 3. Dispatch debuggers dynamically.

Blink results

1. Simple: Add 10 K SLOC of new code. 2. Portable: Support Linux, Windows, Hotspot, J9, GCC, MicrosoW C++. 3. Powerful: Catch FFI bugs.

Problem: GDB does not work at a Java breakpoint.

JNI Managed Java Native C/C++ JDB GDB

Problem: GDB does not work at a Java breakpoint.

JNI Managed Java Native C/C++ JDB GDB Naïve composition How can I print a C variable at a Java breakpoint? Unfortunately, GDB does not work at the Java breakpoint.

Our solu:on: the intermediate agent switches debugger context.

JNI Managed Java Native C/C++ JDB GDB Blink controller We will wake up GDB at a Java breakpoint ‐ Switching debugger context.

Our solu:on: switch debugger context from Java to C.

JDB J‐Agent C‐Agent j2c(){cbreak(); void cbreak(){ eval j2c() breakpoint hit GDB

Our solu:on: switch debugger context from Java to C.

JDB J‐Agent C‐Agent j2c(){cbreak(); void cbreak(){ eval j2c() breakpoint hit GDB print c_var

Our solu:on: switch debugger context from Java to C.

JDB J‐Agent C‐Agent j2c(){cbreak(); void cbreak(){ eval j2c() return;} return;} j2c() completed breakpoint hit continue GDB print c_var

Problem: GDB does not understand JNI calling conven:ons.

JNI Managed Java Native C/C++ JDB GDB How did the program reach the current breakpoint? How can I tell you the calling context? Unfortunately, GDB does not understand JNI transiNons. Naïve composition

jping(i) cpong(j)

Problem: GDB does not understand JNI calling conven:ons.

j2j_call j2c_call main jping(3) cpong(2) Problem: GDB does not understand JNI calling conven:ons. main jping(3) cpong(2) JDB stack GDB stack

j2j_call j2c_call c2j_call main jping(3) cpong(2) jping(1) Problem: GDB does not understand JNI calling conven:ons. main jping(3) jping(1) cpong(2) JDB stack GDB stack GDB does not understand JNI calling convenNon.

j2j_call j2c_call c2j_call j2c_call main jping(3) cpong(2) jping(1) cpong(0) Problem: GDB does not understand JNI calling conven:ons. main jping(3) jping(1) cpong(0) cpong(2) JDB stack GDB stack GDB does not understand JNI calling convenNon.

j2j_call j2c_call c2j_call j2c_call main jping(3) jping(1) cpong(0) cpong(2) main jping(3) cpong(2) jping(1) cpong(0) JDB stack GDB stack with the agent

Our solu:on: translate JNI transi:ons into C transi:ons.

The agent translates JNI calls into C calls – transiNon interposiNon.

j2j_call j2c_call c2j_call j2c_call main jping(3) jping(1) cpong(0) cpong(2) main jping(3) cpong(2) jping(1) cpong(0) JDB GDB with the agent

Our solu:on: compose a calling context.

main jping(3) jping(1) Blink cpong(0) cpong(2)

Our solu:on: controller and intermediate agent

JNI Managed Java Native C/C++ JDB GDB Controller Intermediate agent

I. Problem II. Debugger composi:on

A. Switching debugger context B. Interposing transi:ons

A. Evalua:ng Jeannie mixed‐environment expressions B. Detec:ng FFI bugs

Outline

JNI Mixed-Environment Managed Java Native C/C++

Debugging boundary code

What do I need to debug boundary code?

JNI Mixed-Environment Managed Java Native C/C++

Advanced features to debug boundary code

2. Detec:ng FFI bugs 1. Evalua:ng Jeannie Expressions

jstring name;

Problem: you can not de‐reference opaque pointers in C.

jstring name;

print *name

The name is an

Problem: you can not de‐reference opaque pointers in C.

“smiley”

jstring name;

print *name print `name

Debug All Your Code:   Portable Mixed‐Environment Debugging 

Byeongcheol Lee   Mar:n Hirzel  Robert Grimm  Kathryn McKinley 

1. Leverage legacy code and exis:ng libraries.  2. Match language features to a task. 

Programmers build systems in mul:ple languages. 

Portable mixed‐environment debugging 

Portable mixed‐environment debugging 

1. Leverage legacy code and exis:ng libraries.  2. Match language features to a task. 

Programmers build systems in mul:ple languages. 

The problem 

The problem with single‐environment debugging 

0 

The problem with single‐environment debugging 

0 

Our goal 

Our contribu:on and results  Composi:on 

1. Add an intermediate agent.  2. AOach single‐environment debuggers.  3. Dispatch debuggers dynamically. 

Blink results 

1. Simple: Add 10 K SLOC of new code.  2. Portable: Support Linux, Windows, Hotspot, J9,  GCC, MicrosoW C++.  3. Powerful: Catch FFI bugs. 

Problem: GDB does not work at a Java breakpoint.  

Problem: GDB does not work at a Java breakpoint.  

JNI Managed Java Native C/C++ JDB GDB Naïve composition How can I print a C variable at a  Java breakpoint?  Unfortunately, GDB does not  work at the Java breakpoint. 

Our solu:on: the intermediate agent switches debugger context. 

JNI Managed Java Native C/C++ JDB GDB Blink controller We will wake up GDB at a Java  breakpoint ‐ Switching  debugger context. 

Our solu:on: switch debugger context from Java to C. 

JDB  J‐Agent  C‐Agent  j2c(){cbreak();  void cbreak(){  eval j2c() breakpoint hit GDB

Our solu:on: switch debugger context from Java to C. 

JDB  J‐Agent  C‐Agent  j2c(){cbreak();  void cbreak(){  eval j2c() breakpoint hit GDB print c_var

Our solu:on: switch debugger context from Java to C. 

JDB  J‐Agent  C‐Agent  j2c(){cbreak();  void cbreak(){  eval j2c() return;}  return;}  j2c() completed breakpoint hit continue GDB print c_var

Problem: GDB does not understand JNI calling conven:ons. 

JNI Managed Java Native C/C++ JDB GDB How did the program reach the  current breakpoint?  How can I tell you the calling  context?  Unfortunately, GDB does not  understand JNI transiNons.  Naïve composition

jping(i)  cpong(j) 

Problem: GDB does not understand JNI calling conven:ons. 

j2j_call j2c_call main  jping(3)  cpong(2)  Problem: GDB does not understand JNI calling conven:ons.  main  jping(3)  cpong(2)  JDB stack GDB stack

j2j_call j2c_call c2j_call main  jping(3)  cpong(2)  jping(1)  Problem: GDB does not understand JNI calling conven:ons.  main  jping(3)  jping(1)  cpong(2)  JDB stack GDB stack GDB does not  understand JNI  calling  convenNon. 

j2j_call j2c_call c2j_call j2c_call main  jping(3)  jping(1)  cpong(0)  cpong(2)  main  jping(3)  cpong(2)  jping(1)  cpong(0)  JDB stack GDB stack with the agent

Our solu:on: translate JNI transi:ons into C transi:ons. 

The agent  translates JNI  calls into C calls  – transiNon  interposiNon. 

j2j_call j2c_call c2j_call j2c_call main  jping(3)  jping(1)  cpong(0)  cpong(2)  main  jping(3)  cpong(2)  jping(1)  cpong(0)  JDB GDB with the agent

Our solu:on: compose a calling context. 

main  jping(3)  jping(1)  Blink cpong(0)  cpong(2) 

Our solu:on: controller and intermediate agent 

JNI Managed Java Native C/C++ JDB GDB Controller Intermediate  agent 

I. Problem  II. Debugger composi:on 

A. Switching debugger context  B. Interposing transi:ons 

A. Evalua:ng Jeannie mixed‐environment expressions  B. Detec:ng FFI bugs 

Outline 

Debugging boundary code 

What do I need to debug boundary  code? 

Advanced features to debug boundary code 

2. Detec:ng FFI bugs  1. Evalua:ng Jeannie Expressions 

Problem: you can not de‐reference opaque pointers in C. 

print *name 

The name is an 

Problem: you can not de‐reference opaque pointers in C. 

“smiley” 

print *name  print `name 

The name is an 

The Jeannie  backNck gives me  eyes to see the  Java world. 

Our solu:on: use Jeannie expression 

“smiley” 

print *name  print `name 

The name is an 

How can I evaluate  the Jeannie  expression? 

Our solu:on: use Jeannie expression. 

Build abstract syntax tree 

Evaluate AST in BoOom‐up order. 

JDB  Agent  GDB $vc1 = name

Evaluate AST in BoOom‐up order. 

JDB  Agent  GDB $vc1 = name $vj2 = $vc1

Evaluate AST in BoOom‐up order. 

JDB  Agent  GDB $vc1 = name $vj2 = $vc1 Print $vj2

“smiley” 

Advanced features 

B. Detec:ng FFI bugs  A. Evalua:ng Jeannie Expressions 

C code 

Problem: you may misuse foreign func:on interface. 

C code  The NULL is invalid. The java-gnome bug 576107 crashes the J9 JVM.

Problem: you may misuse foreign func:on interface. 

C code  Agent  GDB The NULL is invalid. The java-gnome bug 576107 crashes the IBM J9 SR5.