LLVM(Low Level Virtual Machine), Clang and GDK · 2012. 10. 30. · LLVM(Low Level Virtual Machine), Clang and GDK 10th Kandroid Conference . 10th Kandroid Conference ... (Dalvik

www.kandroid.org 운영자 : 양정수 (yangjeongsoo at gmail.com), 닉네임: 들풀

2012. 10. 26.

The Gate of the AOSP #3 : Externals & Extras

LLVM(Low Level Virtual Machine), Clang and GDK

10th Kandroid Conference



1. Background History

• LLVM and RenderScript

• NDK : Current State and Issues(limitations)

2. LLVM(Low Level Virtual Machine)

• Why/What is LLVM?

• LLVM IR(Intermediate Representation)

• Lifetime long optimization / Multi-stage optimization

3. Clang : LLVM Compiler Frontend

• Why new Compiler Frontend : Motivation and Features

• Clang Architecture

• Integrate clang into IDEs – Clang and EClipse CDT

4. Clang/LLVM vs. GCC Issues and GDK git branch

• Issue #1 : LLVM vs. GCC Optimization

• Issue #2 : Clang vs. GCC Static Analysis

• GDK : What is GDK?

• GDK : Why GDK uses Clang/LLVM?

3 10th Kandroid Conference - www.kandroid.org

RenderScript offers

a high performance 3D graphics rendering and compute API

at the native level, which you write in the C (C99 standard).

The main advantage :

• Portability

• Performance

• Usability

The main disadvantage :

• Development complexity

• Debugging visibility

• Less features

The general guideline for OpenGL and RenderScript

• Android Framework OpenGL API

• OpenGL and NDK

• RenderScript

LLVM and RenderScript


• Develop a solution to providing a solid 60fps for our application

frameworks

• Has to work well with Dalvik

• Has to work with existing hardware

• Has to scale to future hardware without requiring developers to rewrite

their applications

• Developed applications must be portable across a variety of hardware.

ARM v5, v7, NEON, x86, SSE, GPUs, DSPs

• Good performance across all devices instead of peak performance for one

device at the expense of others

• Build a forward looking 3D graphics and compute API

Source : http://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdf

LLVM and RenderScript : RenderScript Goals

http://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdfhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdfhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdf


Native Layer

(RenderScript)

Native Layer

(LLVM Code)

Reflected Layer

(C99)

helloworld.rs

helloworld.bc

ScriptC_

helloworld

.java

ScriptField_

xxxxxxxxx

.java

llvm-rs-cc

App Java

Sources

App Java

Sources



APK file

Native Layer

(LLVM Code)

Reflected Layer

helloworld.bc

ScriptC_

helloworld

.java

Framework Layer

App Java

Sources

App Java

Sources

App Java

Sources Dalvik

JIT Compiler

libbcc

LLVM based

Jit compiler

System lib.

.bc files

Multicore CPUs

GPUs/DSPs



Android Runtime

(Dalvik VM)

RenderScript Runtime

(LLVM)

Reflected Layer

helloworld.bc

ScriptC_

helloworld

.java

ScriptField_

xxxxxxxxx

.java

App Java

Sources

memory

Memory

Allocation

Read/Write

Read/Write

Memory

Bind



Library Linking option 3 4 5,6,7 8 9(10) 14

c default ○ ○ ○ ○ ○ ○

math default ○ ○ ○ ○ ○ ○

c++ default ○ ○ ○ ○ ○ ○

log -llog ○ ○ ○ ○ ○ ○

zlib -lz ○ ○ ○ ○ ○ ○

Dynamic Linker -ldl ○ ○ ○ ○ ○ ○

OpenGL ES 1.x

-lGLESv1_CM.so ○ ○ ○ ○ ○

OpenGL ES 2.0

-lGLESv2.so ○ ○ ○ ○

jnigraphics -ljnigrahics ○ ○ ○

OpenSL/ES -lOpenSLES ○ ○

Android Native

Application API -landroid ○ ○

OpenMAX AL -lOpenMAXAL ○

NDK : Current State and Issues(limitations)


Hardware Platform

User Applications

Kernel

System Call Interface

glibc

Architecture Dependent Kernel Code

User

Space

Kernel

Space

NPTL

(pthread)

bionic

libc

lib

cutils

NDK : Current State and Issues(limitations) – C libc


Hardware Platform

User Applications

Kernel

System Call Interface

glibc

Architecture Dependent Kernel Code

User

Space

Kernel

Space

NPTL

(pthread)

bionic

libc

lib

cutils

gnu-

libstdc++ libstdc++

gabi++

stlport

gnustl

libutils

libbinder

NDK : Current State and Issues(limitations) – C++ libc


C++ Exceptions C++ RTTI Standard Library

system No No No

gabi++ No Yes No

stlport No Yes Yes

gnustl Yes Yes Yes

The Android platform provides a very minimal C++ runtime support library

(/system/lib/libstdc++) and corresponding headers for it in the NDK.

By default, this 'system' runtime does *not* provide the following:

- Standard C++ Library support (except a few trivial headers).

- C++ exceptions support

- RTTI support

The only headers provided here are the following:

cassert cctype cerrno cfloat climits cmath csetjmp csignal cstddef cstdint

cstdio cstdlib cstring ctime cwchar new stl_pair.h typeinfo utility

NDK : Current State and Issues(limitations) – C++ libc


What is LLVM?

• LLVM Project History : This project started in 2000 at the University of Illinois at

Urbana-Champaign, under the direction of Vikram Adve and Chris Lattner.

• LLVM Compiler Infrastructure

“a design and implementation of a compiler infrastructure which supports a

unique multi-stage optimization system. This system is designed to support

extensive interprocedural and profile-driven optimizations, while being efficient

enough for use in commercial compiler systems”

- In 2002, Chris Lattner stated a definition of the LLVM in his master‟s thesis

“a compiler framework that aims to make lifelong program analysis and

transformation available for arbitrary software and in a manner that is

transparent to programmers”

- In 2004, Vikram Adve and Chris Lattner provided a further description of the LLVM


Knowledge Base : Compiler Infrastructure (1)

source program

modified source program

target assembly program

relocatable machine code

target machine code

Preprocessor

Compiler

Assembler

Linker library files

relocatable object files

Loader (+ fork & exec)

Memory


gcc binutils glibc

gcc

cpp

cc1

as

collect2

ld

(Soft-Link)

ld.gold

ld.bfd link script

CRT*

library

Source (.c and .h)

Preprocessed source (.i or .ii)

Asm (.s)

Relocatable (.o)

Binary

(Executable)

Compiler driver vs. compiler proper

The executable gcc is not a compiler proper, but a compiler driver


gcc --save-temp



Lexical Analyzer

Parser (syntax

& semantic analyzer)

Intermediate Code

Generator

Code Optimizer

Code Generator

token stream

Intermediate

representation

Intermediate

representation

Symbol

Table

Name + Attribute

Attribute

• Type

• Scope

• Offset

machine

independent

machine

dependent

assembly code

character stream

frontend

backend

frontend

middle-end

backend

CFG

Language

Expression

yacc,

bison

Parsing

table

Yacc : LALR(1) Parser Generator

lex,

flex

Regular

Expression &

Action Code


What is LLVM?

$ svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm

$ cd llvm/tools ; svn co http://llvm.org/svn/llvm-project/cfe/trunk clang

$ cd ../projects ; svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk compiler-rt

$ svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite

$ cd ../.. ; mkdir build ; cd build/ ; ../llvm/configure ; make

$ export PATH=/Release+Asserts/bin/:$PATH:.

$ cat > hello.c

#include

int main(void) {

printf("Hello LLVM\n"); return 0;

}

$ clang -emit-llvm -O0 -c hello.c -o hello.bc

$ llc hello.bc # result : hello.s

$ lli hello.bc

Hello LLVM

$ gcc hello.s -o hello

$ ./hello

Hello LLVM

$ llvm-dis hello.bc # result : hello.ll

$ vi hello.ll

# [12 x i8] c"Hello LLVM

=> [13 x i8] c"Hello Clang

# [12 x i8]* @.str

=> [13 x i8]* @.str

$ llvm-as hello.ll # result : hello.bc

$ lli hello.bc

Hello Clang


What is LLVM ? - LLVM Tools (1)

• Basic Commands

– llvm-as : LLVM assembler (LLVM ASM (.ll) → bitcode (.bc))

– llvm-dis : LLVM disassembler (bitcode (.bc) → LLVM ASM (.ll))

– opt : LLVM optimizer

– llc : LLVM static compiler (bitcode (.bc) → Machine ASM (.s))

– lli : directly execute programs from LLVM bitcode

– llvm-link : LLVM linker (bitcodes (.bc) -> bitcode (.bc))

– llvm-ar : LLVM archiver

– llvm-ranlib : Generate index for LLVM archive

– llvm-nm : list LLVM bitcode and object file‟s symbol table

– llvm-config : Print LLVM compilation options

– llvm-sterss : generate random .ll files

– llvm-diff : LLVM structural „diff‟

– llvm-prof : print execution profile of LLVM program

– llvm-cov : emit coverage information


• Debugging Tools

– bugpoint : automatic test case reduction tool

– llvm-extract : extract a function from an LLVM module

– llvm-bcanalyzer : LLVM bitcode analyzer

• Developer Tools

– FileCheck : Flexible pattern matching file verifier

– tblgen : Target Description To C++ Code Generator

– lit : LLVM Integrated Tester

– llvm-build : LLVM Project Build Utility

What is LLVM ? - LLVM Tools (1)


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What is LLVM?

Chris Lattner Shih-Wei Liao


Upstream Major Releases

• 3.1 (May 2012) Includes AddressSanitizer, a fast memory error detector at runtime

• 3.0 (Dec 2011) GCC frontend(llvm-gcc) is no longer supported, and not included in the release

Supports MIPS target

• 2.1 (Sep 2007) Includes its own native C and Objective-C front-end (clang)

• 1.8 (Aug 2006) Supports DWARF debugging, ARM target

• 1.6 (Nov 2005) Supports Mac OS X

• 1.4 (Dec 2004) Supports PowerPC

• 1.0 (Oct 2003) : The first public release - Includes stable C compiler, beta C++ compiler

- Supports X86, Sparc

android/external/llvm git branch

• 368 line diff from LLVM upstream!

• Mostly patches for legacy JIT path (no longer used - essentially dead code)

• Stripped down a bit to fit on current tablet/smartphone

• No debugging support currently

(since we don't emit DWARF from llvm-rs-cc today)

source : http://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdf

What is LLVM?

http://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdfhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdfhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdfhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdf


LLVM Life Long Time Optimization & IR

• LLVM enables life long time optimization

• Why is the whole optimization possible with LLVM?

– LLVM is well-defined and modular architecture.

– It is easy to make a new compiler/optimizer with LLVM.

– Powerful IR(LLVM Virtual Instruction Set and Type system)

and IR’s long lifetime

Source Code

Object Code

Executable Code

Running Code

Profile

Compile-time Optimization

Link-time Optimization

Run-time

Optimization

Off-line Optimization Install-time

Optimization

AOT vs. JIT


C

Frontend C

Code

LLVM

Optimizer

Machine

Code

Generator

ARM

Code

Bitcode

(LLVM IR)

A C Compiler based on LLVM




– LLVM 기반 컴파일러가 소스 코드를 최적화하거나 기계어 코드를 생성할 때, 내부적으로 유지하는 중간 코드

– A Low-level RISC-like Virtual Instruction Set

(Example) %a = add i32 4, %b (i32 : b+4의 결과는 32비트 정수 타입)

• LLVM IR Features

– Language-independent Instruction Set

– Instruction in SSA(Static Single Assignment form)

• SSA : Each variable is assigned exactly once.

(Example of SSA transformation) X=1; X=2; Y=X ⇒ X1=1; X2=2; Y=X

• It‟s feasible to do fast analysis of bitcode.

– Type System

• Supporting types such as integer, float, pointer, array, vector, structure,

function



• IR Example

< C Code >

< LLVM IR Assembly Code >



LLVM : A Collection of Libraries

• LLVM Design

– It is designed as a set of libraries, rather than a monolithic command line

compiler like GCC or an opaque virtual machine like the JVM

• The Number of LLVM Libraries : 82 (LLVM 3.1)

※ LLVM은 라이브러리 형태로 모듈화가 잘 되어 있어서, 필요한 형태의 최적화, 새로운 최적화 및 코드 생성 기법 추가 등을 빠르게 할 수 있음


LLVM Optimization (Compile-Time)

Source

Code

Compile-Time

Optimizer Frontend

Object

Code

Bitcode

(LLVM IR)

1. Perform language-specific optimization

(ex, optimizing closures in languages with higher-order functions)

2. Translate source program to LLVM code : required

(synthesizing as much useful LLVM type information as possible,

especially to expose pointer, structures, and arrays)

3. Invoke LLVM passes for global or interprocedural optimizations at module level

Source : Getting to know the LLVM compiler, Guobin YE, August 19, 2011


LLVM Optimization (Link-Time)

Object Code

Object Code Link-Time

Optimizer

Object Code

∙∙∙

Executable

Code

Bitcode

(LLVM IR)

LLVM link-time optimizer can use the optimized information to improve its performance of

interprocedural optimizations at link-time.

The design of the compile- and link-time optimizers in LLVM permit the use of a well-known

technique for speeding up interprocedural analysis. At compile-time, interprocedural

summaries can be computed for each function in the program and attached to the

LLVM bytecode. The link-time interprodecural optimizer can then process these

interprocedural summaries as input instead of having to compute result from scratch.



The job of linker is to combine the object files generated by compiler and libraries to form an

executable program. The GOLD is a new linker written in C++, which is developed by Ian Lance

Taylor and was added to the GNU Binary Utilities(binutils) in 2008. The goal of the gold linker

is to be faster than the GNU linker, and also enable link-time (global) optimization (LTO).

The gold linker can only be used for ELF operating systems such as GNU and Linux.


LLVM Optimization (Link-Time)

gcc

cpp

cc1

as

collect2

ld

(Soft-Link)

ld.gold

ld.bfd link script

CRT*

library

Source (.c and .h)

Preprocessed source (.i or .ii)

Asm (.s)

Relocatable (.o)

Binary

(Executable)

gcc --save-temps


LLVM Optimization (Runtime)

Executable

Bitcode

Machine

Code

Generator

Executable

Machine Code

Hot

Spot

Runtime

Optimizer

Hot

Spot

optimized

hot spot

bitcode after machine code

generation, replaced

after first

running,

hot spot

found

Running

1

2

3

4

5


Some “hot” functions may not be able to defined and optimized at compile-time,

except the program is running. The main purpose of run-time optimizer is to

overcome this disadvantage. Run-time optimizer monitors the running program in real-

time, if the “hot” functions are detected, run-time optimizer will reoptimize the function.

“When a hot loop region is detected at runtime, a runtime instrumentation library

instrument the executing native code to identify frequently-executed paths within that

region. Once hot paths are identified, we duplicate the original LLVM code into a trace,

perform LLVM optimization on it, and then regenerate native code into a software-

managed trace cache. We then insert branches between the original code and the new

native code.”

Chris Lattner and Vikram Adve, “LLVM: A Compilation Framework for Lifelong Program

Analysis & Transformation”, 2004, Proc. of the 2004

International Symposium on Code Generation and Optimization (CGO'04), Palo

Alto, California.


LLVM Optimization (Runtime)


LLVM Optimization (Idle time)

“Some transformations are too expensive to perform at run-time, even given an

efficient representation to work with. For these transformations, the run-time optimizer

gathers profile information, serializing it to disk … when idle time is detected on the user‟s

computer, on offline reoptimizer is used to perform the most aggressive profile-

driven optimizations to the application”

Compared to traditional profile-guided optimizers, the different of the LLVM offline, idle-

time reoptimizer is that it can use profile information gather from run-time optimizer with

the LLVM bytecode to reoptimize and recompile the application, and perform aggressive

profile-driven interprocedural optimizations without competing with the application for

processor cycles.



LLVM Performance (Execution Time)

• Benchmark Program : SPEC 2000

source : http://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdf

Optimization Level

http://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdfhttp://llvm.org/pubs/2008-10-04-ACAT-LLVM-Intro.pdf


What is Clang? (in Wikipedia)

• Clang

– A compiler front-end for the C, C++, Objective-C, and Objective-C++

programming languages. It uses LLVM as its back-end and has been

part of its releases since LLVM 2.6

• Why not GCC for LLVM front-end ?

– GCC is a large and somewhat cumbersome system to develop

– Apple software makes heavy use of Objective-C, but the Objective-C

front-end in GCC is a low priority

– GCC does not fit smoothly into Apple‟s IDE

– GCC is GPL V3 licensed, but LLVM has a BSD-like license which

permits including the source into proprietary software

– So Apple chose to develop a new compiler front-end from scratch. And

the Clang project was open-sourced in July 2007.


Structure of Clang Compiler

C/C++, Objective C/C++

Code

Frontend

LLVM Compile-Time Optimizer

LLVM Link-Time Optimizer

Machine Code Generator

Linker

Executable Machine Code

LLVM

IR

Clang

LLVM

GCC linker

What is Clang?


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What is Clang?


What is Clang?

Clang is a native front-end of the LLVM compiler, a new generation development tool,

which supports C, C++ and Objective-C languages. As a new compiler front-end, Clang has

many new features, such as fast compile time, low memory use, providing better

support for Apple’s IDE, expressive diagnostics (which provide very useful error and

warning message, clearly point out where exactly the problem is and highlight the errors

code with colorful font), modular design, easy to understand and maintain.

The fast compile time and low memory use are two of major purpose of the Clang, a testing

result published on the Clang performance testing website shows that the time taken by

clang is 2.5 times faster than GCC(version 4.0) on Mac OS/X when parsing “Carbon.h”: the

Abstract Syntax Tree(AST) memory use of Clang is 5 times less than GCC syntax trees on

the Space testing : http://clang.llvm.org/features.html#performance


android/external/clang

• 32 line diff from Clang upstream!

• Support for RGBA vector selection (28 lines)

• Support flag to force "long" to 64-bit (4 lines)

• Ready to upstream now

Source : http://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdf

http://clang.llvm.org/features.htmlhttp://clang.llvm.org/features.htmlhttp://clang.llvm.org/features.htmlhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdfhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdfhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdfhttp://llvm.org/devmtg/2011-11/Hines_AndroidRenderscript.pdf


Structure of Clang (Frontend)

C/C++ Source Code

Lexer & Parser

Semantic Analyzer

LLVM Code Generator

Bitcode

Preprocessor

AST

(Abstract

Syntax Tree)

• Syntax checking

• Semantic analysis

• Type checking

• Processing C/C++

macros (#...)

Static Code Analyzer • Finding runtime

bugs


Clang Supports Expressive Diagnostics

• Example

< Sample code with compile-time error >

< Error messages in clang compiler >

< Error messages in GCC >


Clang Performance (Compile Time)

• Test Environment

– Benchmark Program : 176.gcc (in SPECINT 2000)

– Including 65 source files, LOC : 205,760

– Compile option : -O0 –g

– Tested at 2009.06.26

source : http://clang.llvm.org/performance.html

http://clang.llvm.org/performance.htmlhttp://clang.llvm.org/performance.htmlhttp://clang.llvm.org/performance.html


Clang Static Analyzer

• Clang Static Analyzer

– 컴파일 시간에 실행 시간에 발생할 수 있는 오류를 미리 예측

• 실행시간 분석보다 정확도는 떨어지지만 빠르게 분석할 수 있는 장점이 있음

• Clang Command

– clang –analyze

• Example

< foo.c >

< clang과 gcc 수행 결과 >


Eclipse CDT for Clang/LLVM

• Eclipse CDT 홖경에서 Clang/LLVM 빌드 홖경 지원

• A Bachelor‟s Thesis in Finland (Mar. 2011)

– Refer http://code.google.com/p/llvm4eclipsecdt/

< A snap shot >

http://code.google.com/p/llvm4eclipsecdt/


LLVM and GCC

• LLVM은 단일 IR로 다양한 형태(compile-time, link-time, runtime, offline)의 최적화 지원 가능하지만 GCC는 compile-time 과 gold linker 사용시에 한정된 link-time에서의 최적화만 가능

• LLVM은 BSD License로 소스 코드 공개의 의무가 없으나, GCC는 GPL로 소스 코드 공개 의무 있음

• LLVM, GCC 누가 더 성능 좋은 코드를 만들어 내는 것은 논의 대상이 아니며, 대신 새로운 최적화 기법을 추가하는 데 있어서, LLVM이 GCC 보다 쉽게 접근할 수 있는 구조인 것은 명확함

• GCC는 1987년 이후로 다양한 응용과 타겟 지원을 통하여 검증된 컴파일러이지만, LLVM은 10년 정도의 역사라 아직 검증된 컴파일러라고 볼 수는 없음

• LLVM은 GCC와 같은 범용적인 응용이 아니라, 응용의 범위를 좁혀서 시험 검증한다고 하면 완성도가 높은 컴파일러에 쉽게 도달 가능함

The LLVM Instruction Set and Compilation Strategy GCC Internals, Diego Novillo

[email protected], November 2007


Clang and GCC

• Clang은 LLVM의 frontend로 시작되었지만, LLVM backend를 사용하여 GCC와 유사한 명령 형태를 지원함

• Clang도 LLVM 처럼 라이브러리 형태로 모듈화가 잘되어 있어서, frontend에 새로운 기능을 추가, 삭제가 GCC에 비하여 용이함

• Clang도 BSD License로 소스 코드 공개의 의무 없음

• Clang은 컴파일 시간에 GCC에 비하여 다양한 오류, 경고를 제공하여 개발자가 디버깅을 쉽게 할 수 있음

• Clang은 컴파일 시간에 오류, 경고에 대한 메시지를 GCC 보다 세밀하게 표현하여 IDE와 통합할 때 유용함

Basic

Lex

Parse

AST

Sema

Analysis

Rewrite

LLVMGen

Core Libraries App Libraries


GDK : What is GDK?

Hooray! We done the GDK building system.

This building system is independent on NDK.

It builds what is should (bitcodes), and then transfer the control

to NDK building system, doing the remaining building.

This code is still ugly. Need cleanup.

gdk git commit id : edde771d8940a6f1b00fd68bcca1486b575e6d9e

Author : Nowar Gu


LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := hello_llvm

LOCAL_CFLAGS := -D NUM=7788

LOCAL_SRC_FILES := hello_llvm.c test.cpp

LOCAL_C_INCLUDES := jni/test-include

include $(BUILD_BITCODE)

include $(CLEAR_VARS)

LOCAL_MODULE := test2

LOCAL_SRC_FILES := test2.c

include $(BUILD_BITCODE)

Android-portable.mk

$ cd ~/android-4.1.1_r1/gdk/samples/hello-llvm/jni

$ export OUT=~/android-4.1.1_r1/out/target/product/generic

$ ../../../gdk-build --ndk-root=~/android-ndk-r8b

GDK : What is GDK? : hello-llvm Sample (1)


$ ../../../gdk-build --ndk-root=/home/jsyang/android-ndk-r8b

Compile Bitcode : hello_llvm


GDK : What is GDK? : bitmap-plasma-llvm Sample (1)

bccReadBC(script_ref, "libplasma_portable.bc",

(const char*)script_ptr, length, 0);

bccLinkFile(script_ref, "/system/lib/libclcore.bc", 0);

bccPrepareExecutable(script_ref,

"/data/data/com.example.plasma.llvm/",

"plasmaLLVM", 0);

native_function

= (pPlasmaType)bccGetFuncAddr(script_ref, "root");

native_function(info.width, info.height,

info.stride, time_ms,

palette, pixels, angle_sin_tab);

plasmaLLVM.cpp

crash


*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***

Build fingerprint: 'google/yakju/maguro:4.1.1/JRO03C/398337:user/release-keys'

pid: 16063, tid: 16063, name: ple.plasma.llvm >>> com.example.plasma.llvm


GDK : What is GDK? : bitmap-plasma-llvm Sample (3)

crash

LLVM Frame : ??


GDK : Why GDK uses Clang/LLVM?

Frame Rate Drawing Performance Comparison - LLVM vs. GCC

Enable the use of cache.

With this check-in, end-to-end LLVM milestone achieved.

For NDK samples, Plasma, running on Nexus-S, 800x480 screen:

• LLVM Time Run: 12.60ms per frame, Avg: 12.57

• GCC Time Run: 50.89ms per frame, Avg: 52.34

LLVM can achieve 80 fps,

while GCC yields 19 fps.

GCC is visibly much slower on my Nexus-S.

gdk git commit ID :

4a395f0e19b3e3f5790ef95fd7b72694cd4296b6

Shihwei Liao


www.kandroid.org

Q & A

Documents

LLVM(Low Level Virtual Machine), Clang and GDK · 2012. 10. 30. · LLVM(Low Level Virtual Machine), Clang and GDK 10th Kandroid Conference . 10th Kandroid Conference ... (Dalvik