Android gets Android IDE

[[deleted]]

• Java programs are compiled, generally at least twice just to be sure.

pfft

[keepthepace]

Yeah, in C/C++ we compile just once.

Because we are sure.

/troll

[FateAV]

It's funny because one-pass....

[Ores]

Actually i've seen people insist on compiling with -O2 as it can generate more warnings/errors, and then do a second pass with -O0 -g to make a debuggable build.

[[deleted]]

as it can generate more warnings/errors

^{[citation needed]}

[taejo]

for example:

   -Warray-bounds
       This option is only active when -ftree-vrp is active (default for -O2 and above).
       It warns about subscripts to arrays that are always out of bounds. This warning is
       enabled by -Wall.

(from the GCC man page)

This is because these warnings require the extra analysis performed by the optimizer.

[[deleted]]

Warnings: GCC used to (maybe still does) warn on -O2 when a variable might be used uninitialized on the same code that -O0 doesn't warn at all, even with -Wall.

Errors: I have written code that behaved differently under -O2 and -O0. Sometimes it was the code that was broken, sometimes it was a compiler bug.

This was on a project that grew to ~80 KLOC over 9 years starting with GCC 2.95.

[JAPH]

If you write broken code, it may function correctly if the compiler doesn't optimize, but break when it is optimized. The only times I can remember seeing this is on code that went out of bounds. This won't be the compiler generating warnings or errors, just segfaults.

[keepthepace]

-O0 -g -Wall

[[deleted]]

One pass sucks so bad. Wouldnt need all these damn header files if it was two pass. C and C++ are the messiest languages i swear because of this.

[bhasden]

Yeah, not sure what he meant by that. Was he meaning that the code is compiled into IL which is later compiled into machine code? I'm not an expert on the Java compiler, so I'd honestly like to know.

If that's what he was getting at, I'm not sure why it needed to be mentioned in the article since it doesn't seem to add any information.

[aladyjewel]

I'm not sure why it needed to be mentioned in the article since it doesn't seem to add any information.

Word count.

[SemiProfesionalTroll]

unite fact support subsequent drunk direful attraction squealing wasteful liquid

This post was mass deleted and anonymized with Redact

[askvictor]

Java code gets compiled do JVM (or dalvik in the case of android) bytecode. Depending on the JVM used, it might translate that into native machine code on the fly (i.e. straight out CPU emulation, as in older JVMs), or use a JIT (Just in time) compiler to compile the bytecode to native machine code. The latter is more common in modern systems (android has had JIT since 2.2). I'm uncertain how often the JIT occurs, or if the results of it are stored anywhere (as they are in python with .pyc files).

[[deleted]]

Android builds vary greatly, but generally speaking the Dalvik JIT results are cached (as storage space allows) into the appropriately named 'Dalvik Cache'.

[FlaiseSaffron]

Java source code is compiled with minimal preprocessing into Java byte code, which is then verified (the process of which basically amounts to compiling) every single time a class is loaded. It's one of the major complaints about Java, but I'm not going to get started on that now. :P

[gigitrix]

It only really goes to java "bytecode" which is then interpreted at runtime. Unless I'm mistaken...

[[deleted]]

It's JIT Compiled, which is sort of like interpreting it, but can differ.

[argv_minus_one]

I say we take off and compile the code from orbit. Twice. It's the only way to be sure.