Android 292 Jrme Pilliet Universit Paris-Est Marne-la-Valle - - PowerPoint PPT Presentation

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Android 292 Jrme Pilliet Universit Paris-Est Marne-la-Valle - - PowerPoint PPT Presentation

Oct 18, 2022 180 likes •468 views

Android 292 Jrme Pilliet Universit Paris-Est Marne-la-Valle Forewords Dynamic languages Semantic determined at runtime Smartphone / Tablet Constraint memory Constraint computing power Android and Dalvik OS most used Java

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Jérôme Pilliet Université Paris-Est Marne-la-Vallée

Android 292

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Forewords

Dynamic languages

Semantic determined at runtime

Smartphone / Tablet

Constraint memory Constraint computing power

Android and Dalvik

OS most used Java technology - Dalvik

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invokedynamic

Example

…

  • .bar(8)

... . . . . invokevirtual java/lang/Object.bar:(I)V invokedynamic ''bar'':(Ljava/lang/Object;I)V class Foo { def bar(a, b=5, c=2:float, d=10) { … } }

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… invokedynamic "bar" (Ljava/lang/Object;I)V bsm: RT.bsm(Lookup, String, MethodType)CallSite ... CallSite bsm(Lookup lookup, String name, MethodType mType) { MethodHandle mh0 = lookup.findVirtual(Foo.class, ''bar'', mType); MethodHandle mh1 = tree(mh0); return new CallSite(mh1); }

  • 1. call bootstrap method
  • 2. bind a CallSite

// example …

  • .bar(8);

... bar(8, 5, 2.0, 10)

invokedynamic

Example

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… invokedynamic "bar" (Ljava/lang/Object;I)V bsm: RT.bsm(Lookup, String, MethodType)CallSite ... CallSite bsm(Lookup lookup, String name, MethodType mType) { MethodHandle mh0 = lookup.findVirtual(Foo.class, ''bar'', mType); MethodHandle mh1 = tree(mh0); return new CallSite(mh1); } bar(8, 5, 2.0, 10)

  • 1. call bootstrap method
  • 2. bind a CallSite
  • 3. next calls

// example …

  • .bar(8);

... MethodHandles Tree

invokedynamic

Example

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… invokedynamic "bar" (Ljava/lang/Object;I)V bsm: RT.bsm(Lookup, String, MethodType)CallSite ... CallSite bsm(Lookup lookup, String name, MethodType mType) { MethodHandle mh0 = lookup.findVirtual(Foo.class, ''bar'', mType); MethodHandle mh1 = mh0.asType(mType); MethodHandle mh2 = MethodHandles.insertArguments(mh1, 1, 5); MethodHandle mh3 = MethodHandles.insertArguments(mh2, 1, 2, 10); return new ConstantCallSite(mh3); } bar(8, 5, 2.0, 10)

  • 1. call bootstrap method
  • 2. bind a CallSite
  • 3. next calls

// example …

  • .bar(8);

... MethodHandles Tree

invokedynamic

Example

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CallSite bsm(Lookup lookup, String name, MethodType mType) { MethodHandle mh0 = lookup.findVirtual(Foo.class, ''bar'', mType); MethodHandle mh1 = mh0.asType(mType); MethodHandle mh2 = MethodHandles.insertArguments(mh1, 1, 5); MethodHandle mh3 = MethodHandles.insertArguments(mh2, 1, 2, 10); return new ConstantCallSite(mh3); } bar(8)

  • (I)V

mh3 = MethodHandles.insertArguments(mh2, 1, 2, 10); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1 = mh0.asType(mType); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

invokedynamic

Example

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CallSite bsm(Lookup lookup, String name, MethodType mType) { MethodHandle mh0 = lookup.findVirtual(Foo.class, ''bar'', mType); MethodHandle mh1 = mh0.asType(mType); MethodHandle mh2 = MethodHandles.insertArguments(mh1, 1, 5); MethodHandle mh3 = MethodHandles.insertArguments(mh2, 1, 2, 10); return new ConstantCallSite(mh3); } bar(8)

  • (I)V

mh3 = MethodHandles.insertArguments(mh2, 1, 2, 10); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1 = mh0.asType(mType); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

invokedynamic

Example

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CallSite bsm(Lookup lookup, String name, MethodType mType) { MethodHandle mh0 = lookup.findVirtual(Foo.class, ''bar'', mType); MethodHandle mh1 = mh0.asType(mType); MethodHandle mh2 = MethodHandles.insertArguments(mh1, 1, 5); MethodHandle mh3 = MethodHandles.insertArguments(mh2, 1, 2, 10); return new ConstantCallSite(mh3); } bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

invokedynamic

Example

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JSR 292

java.lang.invoke

direct combiner

GuardWithTest insert/bind ... ... findStatic

MethodHandle

findVirtual

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Hotspot

Implementations

Two different implementations

JDK7: Interpreter : stubs in assembler + ricochet frame JIT only constant method handle (static final + invokedynamic)

done by generating java code + classical JIT

JDK8 : Interpreter : written in Java (lambda form) JIT both invokedynamic and method handle

done by generating java code from lambda form + classical JIT

We don't want/can't/think it's a good idea to generate java code

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Android 292

Mini-Interpreter

MethodHandle.invoke

mh.asType().invokeExact() mh.asType is a MH tree

invokedynamic

CS.getTarget().invokeExact()

MethodHandle.invokeExact

MethodHandle direct direct call, no intermediate stack frame MethodHandle Tree mini-interpreter specific calling convention, one specific stack frame

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Android 292

Mini-Interpreter

is a combiner ? mh.invokeExact(...) javaCall : code = generateCode(mh) mini-interpreter code exists ? yes no no yes direct call mini_interpreter.execute(code)

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Move/permute/insert/filter/... stack values in one stack frame Use an indirection encoded as integers to avoid to move values

A stack frame of the mini interpreter is known and typed

Do most of the operations on 3 raw types (Object, 32bits, 64bits)

Can reuse the same mini-interpreter code for several method handle trees

The mini-interpreter is register based (like Dalvik) No mini-interpreter

Hijack Dalvik interpreter to re-use Dalvik opcodes Add just one new opcode for the mini-interpreter

Android 292

Mini-Interpreter

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Android 292

Data Structures

int nb_r; // number of registers int nb_rv; // number of return values MethodHandle[] mhs; // list of methodhandles byte[] code; // code of methodhandle tree … CombinerMethodHandle.java int bd32; // 32bits bound primitive long bd64; // 64bits bound primitive Object bo; // bound object … BoundMethodHandle.java int kind; // invokestatic, invokevirtual, combiner Method* m; // Android raw method pointer int index; // field slot/vtable index … MethodHandle.java

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MethodHandle Activation Header Code Reference (Java) Return Values (known types) Registers (32 bits integers) MH arguments Stack

a : argument rv : return value m : methodhandle bd : bound data bo : bound object 32/64bits

Register number representation Numbers known

  • n the first execution

Mini Interpreter Program Counter

Android 292

Mini-Interpreter Stack Frame

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Android 292

Mini-Interpreter

is a combiner ? mh.invokeExact(...) mini_interpreter.execute(code) javaCall : code = generateCode(mh) yes no yes direct call mini-interpreter code exists ? no

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MethodHandle Activation Header 0x... 8 int rv r a 1 2 3 code { const r0 a0, const r2 bd0, const r1 bd1, move r3 r2, move r2 r1, const r1 bd2, invoke_mh rv0 m3 r2 1, const r2 rv0, invoke_mh 0 m4 r0 4 } nb_r = 0 nb_rv = 0

Android 292

Example

program counter = code + 0

bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

mhs = { mh3_2, mh3_1, mh2, mh1_1, mh0 }

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MethodHandle Activation Header 0x... 8 int rv r a 1 2 3 code { const r0 a0, const r2 bd0, const r1 bd1, move r3 r2, move r2 r1, const r1 bd2, invoke_mh rv0 m3 r2 1, const r2 rv0, invoke_mh 0 m4 r0 4 } nb_r = 1 nb_rv = 0 a0

Android 292

Example

program counter = code + 1

bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

mhs = { mh3_2, mh3_1, mh2, mh1_1, mh0 }

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MethodHandle Activation Header 0x... 8 int rv r a 1 2 3 code { const r0 a0, const r2 bd0, const r1 bd1, move r3 r2, move r2 r1, const r1 bd2, invoke_mh rv0 m3 r2 1, const r2 rv0, invoke_mh 0 m4 r0 4 } nb_r = 2 nb_rv = 0 a0 bd0/32

Android 292

Example

program counter = code + 2

bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

mhs = { mh3_2, mh3_1, mh2, mh1_1, mh0 }

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MethodHandle Activation Header 0x... 8 int rv r a 1 2 3 code { const r0 a0, const r2 bd0, const r1 bd1, move r3 r2, move r2 r1, const r1 bd2, invoke_mh rv0 m3 r2 1, const r2 rv0, invoke_mh 0 m4 r0 4 } nb_r = 3 nb_rv = 0 a0 bd1/32 bd0/32

Android 292

Example

program counter = code + 3

bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

mhs = { mh3_2, mh3_1, mh2, mh1_1, mh0 }

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MethodHandle Activation Header 0x... 8 int rv r a 1 2 3 code { const r0 a0, const r2 bd0, const r1 bd1, move r3 r2, move r2 r1, const r1 bd2, invoke_mh rv0 m3 r2 1, const r2 rv0, invoke_mh 0 m4 r0 4 } nb_r = 4 nb_rv = 0 a0 bd2/32 bd1/32 bd0/32

Android 292

Example

program counter = code + 6

bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

mhs = { mh3_2, mh3_1, mh2, mh1_1, mh0 }

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MethodHandle Activation Header 0x... 8 int rv r a 1 2 3 code { const r0 a0, const r2 bd0, const r1 bd1, move r3 r2, move r2 r1, const r1 bd2, invoke_mh rv0 m3 r2 1, const r2 rv0, invoke_mh 0 m4 r0 4 } mhs = { mh3_2, mh3_1, mh2, mh1_1, mh0 } nb_r = 4 nb_rv = 1 code + 7 2.0 float a0 bd2/32 rv0/32 bd0/32

Android 292

Example

program counter = code + 8

bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

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MethodHandle Activation Header 0x... 8 int rv r a 1 2 3 code { const r0 a0, const r2 bd0, const r1 bd1, move r3 r2, move r2 r1, const r1 bd2, invoke_mh rv0 m3 r2 1, const r2 rv0, invoke_mh 0 m4 r0 4 } mhs = { mh3_2, mh3_1, mh2, mh1_1, mh0 } nb_r = 4 nb_rv = 1 code + 9

Android 292

Example

program counter = code + 9

bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

2.0 float a0 bd2/32 rv0/32 bd0/32

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MethodHandle Activation Header 0x... 8 int rv r a 1 2 3 code { const r0 a0, const r2 bd0, const r1 bd1, move r3 r2, move r2 r1, const r1 bd2, invoke_mh rv0 m3 r2 1, const r2 rv0, invoke_mh 0 m4 r0 4 } nb_r = 4 nb_rv = 1

Android 292

Example

code + 9 program counter = code + 9

bar(8)

  • (I)V

mh3_2 = MethodHandles.insertArguments(mh3_1, 2, 10); bar(8,10)

  • (II)V

↳ mh3_1 = MethodHandles.insertArguments(mh2, 1, 2); bar(8,2,10)

  • (III)V

↳ mh2 = MethodHandles.insertArguments(mh1_1, 1, 5); bar(8,5,2,10)

  • (IIII)V

↳ mh1_1 = MethodHandles.filterArgument(mh0, 2, i2F); bar(8,5,2.0,10)

  • (IIFI)V

↳ mh0 = lookup.findVirtual(Foo.class, ''bar'', mType);

mhs = { mh3_2, mh3_1, mh2, mh1_1, mh0 } 2.0 float a0 bd2/32 rv0/32 bd0/32

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Roadmap

Master thesis

Prototype with Android 4.0 Generation DEX code

Thesis (start sept 2012)

Fresh restart with Android 4.2 Android SDK compiles with java 7 Add instructions : ldc_method*, invokeExact, invokeGeneric … Untainted implementation of java.lang.invoke No SwitchPoint yet ! Implementation of direct method handle in the interpreter Implementation of the mini interpreter

...

Lambda proxy ? (Java 8)

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Goal

Dalvik : a ''Java'' VM like the other

Open Questions

Perf ? Can Hotspot Zero reuse the same scheme ? Not obvious, java bytecode uses a stack Can we transform the mini interpreter code to JIT instructions ? Let say yes, all arguments of the opcodes are known A specific abstract interpretation should work.

Conclusion

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Jérôme Pilliet <pilliet@univ-mlv.fr> Université Paris-Est Marne-la-Vallée

Android 292

https://bitbucket.org/jpilliet/android-292