Ubuntu14.04下64位Java虚拟机编译过程

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引言

Java程序员应该都听过HotSpot JVM,它是Sun JDK和Open JDK中所带的虚拟机,也是目前使用范围最广的虚拟机. 不过很多人不知道的是,这个目前“血统纯正”的虚拟机最初并非由Sun公司开发,而是由一家名为”Longview Technologies”的小公司设计的;甚至这个虚拟机最初并非是为Java语言开发的,它来源于Strongtalk VM,而这款虚拟机中相当多的技术又是来源于一款支持Self语言实现”达到C语言50%以上的执行效率”的目标而设计的虚拟机,Sun公司注意到了这款虚拟机在JIM编译上有许多优秀的理念和实际效果,在1997年收购了Longview Technologies公司,从而获得了HotSpot VM.

HotSpot VM继承了Sun之前的两款商用VM的优点,同时也有直接的一些优势,如它名称中的HotSpot指的是它的热点代码探测技术.

为了更好地分析这款目前使用最广的Java虚拟机,首先需要将虚拟机源码进行编译。这里选择jdk7进行分析是基于以下原因:

  • hotspot源代码包含在openjdk7中

  • openjdk7包含了jdk的Java代码，所以要用jdk6对这部分代码进行编译。（有点类似于gcc高版本代码要用gcc低版本编译一样）

1.安装依赖项

安装如下依赖即可:

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$ sudo apt-get install build-essential gawk m4 openjdk-6-jdk libasound2-dev libcups2-dev libxrender-dev xorg-dev xutils-dev X11proto-print-dev binutils libmotifs3 libmotif-dev ant

2.openjdk6安装

由于jdk7的很多feature使用java完成,所以它需要一个老版本的jdk来编译它自己,很多的书或者博客会说安装openjdk6就可以,但实际上由于openjdk的一个bug,导致使用openjdk6会出现以下错误: 

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./gamma: relocation error: /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.36.x86_64/jre/lib/amd64/libjava.so: symbol JVM_FindClassFromCaller, version SUNWprivate_1.1 not defined in file libjvm.so with link time reference

真正要安装的是Oracel JDK6,我自己安装的是Oracel JDK 1.6.0_45-b06这个版本.至于如何安装Oracle JDK这样简单的问题就不说了,不知道的童鞋可以看看这个:
安装JDK步骤

3.下载openjdk7源码

最开始我是下载Oracle官网上最新的Openjdk源码，但是发现始终编译不过,从出错信息也查不到原因,所以后面使用了另外一个版本的源码(openjdk-7u6-fcs-src-b24-28_aug_2012),可以在这个链接下载:
openjdk7u6

4.编译脚本

在编译前,需要设置一些条件,由于条件非常多,最好将其写成脚本,如下是我的编译脚本:

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export LANG=C
export ALT_BOOTDIR=/usr/lib/jvm/jdk1.6.0_45
export HOST_BUILD_JOBS=6
export ALLOW_DOWNLOADS=true
export USE_PRECOMPILED_HEADER=true
export BUILD_LANGTOOLS=true
export BUILD_JAXP=true
export BUILD_JAXWS=true
export BUILD_CORBA=true
export BUILD_HOTSPOT=true
export BUILD_JDK=true
export SKIP_DEBUG_BUILD=false
export SKIP_FASTDEBUG_BUILD=true
export DEBUG_NAME=debug
BUILD_DEPLOY=false
BUILD_INSTALL=false
export ALT_OUTPUTDIR=/home/allen/Study/CS/Java/jvm/openjdk/build
unset CLASSPATH
unset JAVA_HOME

编写好之后运行一下,然后输入以下命令检查： 

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$ make sanity

如果检查无误的话会出现如下画面:

之后可以简单的输入make,也可以使用以下命令以保存log:

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$ make 2>&1 | tee $ALT_OUTPUTDIR/build.log

5.编译中遇到的问题

一定会遇到的error如下:

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/opt/jdk1.6.0_31/bin/java  -Xmx896m -Xms128m -XX:PermSize=32m -XX:MaxPermSize=160m -jar /root/openjdk6/build/btjars/generatecurrencydata.jar -o /root/openjdk6/build/lib/currency.data.temp \
                < ../../../src/share/classes/java/util/CurrencyData.properties
Error: time is more than 10 years from present: 1120165200000
java.lang.RuntimeException: time is more than 10 years from present: 1120165200000
        at build.tools.generatecurrencydata.GenerateCurrencyData.makeSpecialCaseEntry(GenerateCurrencyData.java:285)
        at build.tools.generatecurrencydata.GenerateCurrencyData.buildMainAndSpecialCaseTables(GenerateCurrencyData.java:225)
        at build.tools.generatecurrencydata.GenerateCurrencyData.main(GenerateCurrencyData.java:154)

从出错消息也能判断,这个是由于时间超过10年导致的,这个问题很好解决：通过修改openjdk/jdk/src/share/classes/java/util/CurrencyData.properties文件, 把10年之前的时间修改为10年之内即可(把所有的时间格式的时间改为2015以前的十年以内的年数）。下面是我修改后的文件:

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#
# Copyright (c) 2000, 2008, Oracle and/or its affiliates. All rights reserved.
# DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
#
# This code is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License version 2 only, as
# published by the Free Software Foundation.  Oracle designates this
# particular file as subject to the "Classpath" exception as provided
# by Oracle in the LICENSE file that accompanied this code.
#
# This code is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# version 2 for more details (a copy is included in the LICENSE file that
# accompanied this code).
#
# You should have received a copy of the GNU General Public License version
# 2 along with this work; if not, write to the Free Software Foundation,
# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
#
# Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
# or visit www.oracle.com if you need additional information or have any
# questions.
#
formatVersion=1
# Version of the currency code information in this class.
# It is a serial number that accompanies with each amendment, such as 
# 'MAxxx.doc'
dataVersion=151
# List of all valid ISO 4217 currency codes.
# To ensure compatibility, do not remove codes.
all=ADP020-AED784-AFA004-AFN971-ALL008-AMD051-ANG532-AOA973-ARS032-ATS040-AUD036-\
    AWG533-AYM945-AZM031-AZN944-BAM977-BBD052-BDT050-BEF056-BGL100-BGN975-BHD048-BIF108-\
    BMD060-BND096-BOB068-BOV984-BRL986-BSD044-BTN064-BWP072-BYB112-BYR974-\
    BZD084-CAD124-CDF976-CHF756-CLF990-CLP152-CNY156-COP170-CRC188-CSD891-CUP192-CUC931-\
    CVE132-CYP196-CZK203-DEM276-DJF262-DKK208-DOP214-DZD012-EEK233-EGP818-\
    ERN232-ESP724-ETB230-EUR978-FIM246-FJD242-FKP238-FRF250-GBP826-GEL981-\
    GHC288-GHS936-GIP292-GMD270-GNF324-GRD300-GTQ320-GWP624-GYD328-HKD344-HNL340-\
    HRK191-HTG332-HUF348-IDR360-IEP372-ILS376-INR356-IQD368-IRR364-ISK352-\
    ITL380-JMD388-JOD400-JPY392-KES404-KGS417-KHR116-KMF174-KPW408-KRW410-\
    KWD414-KYD136-KZT398-LAK418-LBP422-LKR144-LRD430-LSL426-LTL440-LUF442-\
    LVL428-LYD434-MAD504-MDL498-MGA969-MGF450-MKD807-MMK104-MNT496-MOP446-MRO478-\
    MTL470-MUR480-MVR462-MWK454-MXN484-MXV979-MYR458-MZM508-MZN943-NAD516-NGN566-\
    NIO558-NLG528-NOK578-NPR524-NZD554-OMR512-PAB590-PEN604-PGK598-PHP608-\
    PKR586-PLN985-PTE620-PYG600-QAR634-ROL946-RON946-RSD941-RUB643-RUR810-RWF646-SAR682-\
    SBD090-SCR690-SDD736-SDG938-SEK752-SGD702-SHP654-SIT705-SKK703-SLL694-SOS706-\
    SRD968-SRG740-STD678-SVC222-SYP760-SZL748-THB764-TJS972-TMM795-TMT934-TND788-TOP776-\
    TPE626-TRL792-TRY949-TTD780-TWD901-TZS834-UAH980-UGX800-USD840-USN997-USS998-\
    UYU858-UZS860-VEB862-VEF937-VND704-VUV548-WST882-XAF950-XAG961-XAU959-XBA955-\
    XBB956-XBC957-XBD958-XCD951-XDR960-XFO000-XFU000-XOF952-XPD964-XPF953-\
    XPT962-XSU994-XTS963-XUA965-XXX999-YER886-YUM891-ZAR710-ZMK894-ZWD716-ZWL932-ZWN942-ZWR935
# Mappings from ISO 3166 country codes to ISO 4217 currency codes.
#
# Three forms are used:
# Form 1: <country code>=<currency code>
# Form 2: <country code>=<currency code 1>;<time stamp>;<currency code 2>
# Form 3: <country code>=
# Form 1 is used if no future change in currency is known.
# Form 2 indicates that before the specified time currency 1 is used, from
# the specified time currency 2. The time is given in SimpleDateFormat's
# yyyy-MM-dd-HH-mm-ss format in the GMT time zone.
# Form 3 indicates the country doesn't have a currency (the entry is still
# needed to verify that the country code is valid).
#
# The table is based on the following web sites:
# http://www.din.de/gremien/nas/nabd/iso3166ma/codlstp1/db_en.html
# http://www.bsi-global.com/iso4217currency
# http://www.cia.gov/cia/publications/factbook/indexgeo.html
# AFGHANISTAN
AF=AFN
# \u00c5LAND ISLANDS
AX=EUR
# ALBANIA
AL=ALL
# ALGERIA
DZ=DZD
# AMERICAN SAMOA
AS=USD
# ANDORRA
AD=EUR
# ANGOLA
AO=AOA
# ANGUILLA
AI=XCD
# ANTARCTICA
AQ=
# ANTIGUA AND BARBUDA
AG=XCD
# ARGENTINA
AR=ARS
# ARMENIA
AM=AMD
# ARUBA
AW=AWG
# AUSTRALIA
AU=AUD
# AUSTRIA
AT=EUR
# AZERBAIJAN
AZ=AZM;2008-12-31-20-00-00;AZN
# BAHAMAS
BS=BSD
# BAHRAIN
BH=BHD
# BANGLADESH
BD=BDT
# BARBADOS
BB=BBD
# BELARUS
BY=BYR
# BELGIUM
BE=EUR
# BELIZE
BZ=BZD
# BENIN
BJ=XOF
# BERMUDA
BM=BMD
# Bonaire, Sint Eustatius and Saba
BQ=USD
# BHUTAN
BT=BTN
# BOLIVIA
BO=BOB
# BOSNIA AND HERZEGOVINA
BA=BAM
# BOTSWANA
BW=BWP
# BOUVET ISLAND
BV=NOK
# BRAZIL
BR=BRL
# BRITISH INDIAN OCEAN TERRITORY
IO=USD
# BRUNEI DARUSSALAM
BN=BND
# BULGARIA
BG=BGN
# BURKINA FASO
BF=XOF
# BURUNDI
BI=BIF
# CAMBODIA
KH=KHR
# CAMEROON
CM=XAF
# CANADA
CA=CAD
# CAPE VERDE
CV=CVE
# CAYMAN ISLANDS
KY=KYD
# CENTRAL AFRICAN REPUBLIC
CF=XAF
# CHAD
TD=XAF
# CHILE
CL=CLP
# CHINA
CN=CNY
# CHRISTMAS ISLAND
CX=AUD
# COCOS (KEELING) ISLANDS
CC=AUD
# COLOMBIA
CO=COP
# COMOROS
KM=KMF
# CONGO
CG=XAF
# CONGO, THE DEMOCRATIC REPUBLIC OF THE
CD=CDF
# COOK ISLANDS
CK=NZD
# COSTA RICA
CR=CRC
# COTE D'IVOIRE
CI=XOF
# CROATIA
HR=HRK
# CUBA
CU=CUP
# Cura\u00e7ao
CW=ANG
# CYPRUS
CY=EUR
# CZECH REPUBLIC
CZ=CZK
# DENMARK
DK=DKK
# DJIBOUTI
DJ=DJF
# DOMINICA
DM=XCD
# DOMINICAN REPUBLIC
DO=DOP
# ECUADOR
EC=USD
# EGYPT
EG=EGP
# EL SALVADOR
# USD is also legal currency as of 2001/01/01
SV=SVC
# EQUATORIAL GUINEA
GQ=XAF
# ERITREA
ER=ERN
# ESTONIA
EE=EUR
# ETHIOPIA
ET=ETB
# FALKLAND ISLANDS (MALVINAS)
FK=FKP
# FAROE ISLANDS
FO=DKK
# FIJI
FJ=FJD
# FINLAND
FI=EUR
# FRANCE
FR=EUR
# FRENCH GUIANA
GF=EUR
# FRENCH POLYNESIA
PF=XPF
# FRENCH SOUTHERN TERRITORIES
TF=EUR
# GABON
GA=XAF
# GAMBIA
GM=GMD
# GEORGIA
GE=GEL
# GERMANY
DE=EUR
# GHANA
GH=GHS
# GIBRALTAR
GI=GIP
# GREECE
GR=EUR
# GREENLAND
GL=DKK
# GRENADA
GD=XCD
# GUADELOUPE
GP=EUR
# GUAM
GU=USD
# GUATEMALA
GT=GTQ
# GUERNSEY
GG=GBP
# GUINEA
GN=GNF
# GUINEA-BISSAU
GW=XOF
# GUYANA
GY=GYD
# HAITI
HT=HTG
# HEARD ISLAND AND MCDONALD ISLANDS
HM=AUD
# HOLY SEE (VATICAN CITY STATE)
VA=EUR
# HONDURAS
HN=HNL
# HONG KONG
HK=HKD
# HUNGARY
HU=HUF
# ICELAND
IS=ISK
# INDIA
IN=INR
# INDONESIA
ID=IDR
# IRAN, ISLAMIC REPUBLIC OF
IR=IRR
# IRAQ
IQ=IQD
# IRELAND
IE=EUR
# ISLE OF MAN
IM=GBP
# ISRAEL
IL=ILS
# ITALY
IT=EUR
# JAMAICA
JM=JMD
# JAPAN
JP=JPY
# JERSEY
JE=GBP
# JORDAN
JO=JOD
# KAZAKSTAN
KZ=KZT
# KENYA
KE=KES
# KIRIBATI
KI=AUD
# KOREA, DEMOCRATIC PEOPLE'S REPUBLIC OF
KP=KPW
# KOREA, REPUBLIC OF
KR=KRW
# KUWAIT
KW=KWD
# KYRGYZSTAN
KG=KGS
# LAO PEOPLE'S DEMOCRATIC REPUBLIC
LA=LAK
# LATVIA
LV=LVL
# LEBANON
LB=LBP
# LESOTHO
LS=LSL
# LIBERIA
LR=LRD
# LIBYAN ARAB JAMAHIRIYA
LY=LYD
# LIECHTENSTEIN
LI=CHF
# LITHUANIA
LT=LTL
# LUXEMBOURG
LU=EUR
# MACAU
MO=MOP
# MACEDONIA, THE FORMER YUGOSLAV REPUBLIC OF
MK=MKD
# MADAGASCAR
MG=MGA
# MALAWI
MW=MWK
# MALAYSIA
MY=MYR
# MALDIVES
MV=MVR
# MALI
ML=XOF
# MALTA
MT=EUR
# MARSHALL ISLANDS
MH=USD
# MARTINIQUE
MQ=EUR
# MAURITANIA
MR=MRO
# MAURITIUS
MU=MUR
# MAYOTTE
YT=EUR
# MEXICO
MX=MXN
# MICRONESIA, FEDERATED STATES OF
FM=USD
# MOLDOVA, REPUBLIC OF
MD=MDL
# MONACO
MC=EUR
# MONGOLIA
MN=MNT
# MONTENEGRO
ME=EUR
# MONTSERRAT
MS=XCD
# MOROCCO
MA=MAD
# MOZAMBIQUE
MZ=MZM;2008-06-30-22-00-00;MZN
# MYANMAR
MM=MMK
# NAMIBIA
NA=NAD
# NAURU
NR=AUD
# NEPAL
NP=NPR
# NETHERLANDS
NL=EUR
# NETHERLANDS ANTILLES
AN=ANG
# NEW CALEDONIA
NC=XPF
# NEW ZEALAND
NZ=NZD
# NICARAGUA
NI=NIO
# NIGER
NE=XOF
# NIGERIA
NG=NGN
# NIUE
NU=NZD
# NORFOLK ISLAND
NF=AUD
# NORTHERN MARIANA ISLANDS
MP=USD
# NORWAY
NO=NOK
# OMAN
OM=OMR
# PAKISTAN
PK=PKR
# PALAU
PW=USD
# PALESTINIAN TERRITORY, OCCUPIED
PS=ILS
# PANAMA
PA=PAB
# PAPUA NEW GUINEA
PG=PGK
# PARAGUAY
PY=PYG
# PERU
PE=PEN
# PHILIPPINES
PH=PHP
# PITCAIRN
PN=NZD
# POLAND
PL=PLN
# PORTUGAL
PT=EUR
# PUERTO RICO
PR=USD
# QATAR
QA=QAR
# REUNION
RE=EUR
# ROMANIA
RO=ROL;2008-06-30-21-00-00;RON
# RUSSIAN FEDERATION
RU=RUB
# RWANDA
RW=RWF
# SAINT BARTHELEMY
BL=EUR
# SAINT HELENA
SH=SHP
# SAINT KITTS AND NEVIS
KN=XCD
# SAINT LUCIA
LC=XCD
# SAINT MARTIN
MF=EUR
# SAINT PIERRE AND MIQUELON
PM=EUR
# SAINT VINCENT AND THE GRENADINES
VC=XCD
# SAMOA
WS=WST
# SAN MARINO
SM=EUR
# SAO TOME AND PRINCIPE
ST=STD
# SAUDI ARABIA
SA=SAR
# SENEGAL
SN=XOF
# SERBIA
RS=RSD
# SERBIA AND MONTENEGRO
CS=CSD
# SEYCHELLES
SC=SCR
# SIERRA LEONE
SL=SLL
# SINGAPORE
SG=SGD
# SLOVAKIA
SK=EUR
# SLOVENIA
SI=EUR
# SOLOMON ISLANDS
SB=SBD
# SOMALIA
SO=SOS
# SOUTH AFRICA
ZA=ZAR
# SOUTH GEORGIA AND THE SOUTH SANDWICH ISLANDS
GS=GBP
# SPAIN
ES=EUR
# SRI LANKA
LK=LKR
# SUDAN
SD=SDG
# SURINAME
SR=SRD
# SVALBARD AND JAN MAYEN
SJ=NOK
# Sint Maarten (Dutch part)
SX=ANG
# SWAZILAND
SZ=SZL
# SWEDEN
SE=SEK
# SWITZERLAND
CH=CHF
# SYRIAN ARAB REPUBLIC
SY=SYP
# TAIWAN
TW=TWD
# TAJIKISTAN
TJ=TJS
# TANZANIA, UNITED REPUBLIC OF
TZ=TZS
# THAILAND
TH=THB
# TIMOR-LESTE
TL=USD
# TOGO
TG=XOF
# TOKELAU
TK=NZD
# TONGA
TO=TOP
# TRINIDAD AND TOBAGO
TT=TTD
# TUNISIA
TN=TND
# TURKEY
TR=TRL;2009-12-31-22-00-00;TRY
# TURKMENISTAN
TM=TMT
# TURKS AND CAICOS ISLANDS
TC=USD
# TUVALU
TV=AUD
# UGANDA
UG=UGX
# UKRAINE
UA=UAH
# UNITED ARAB EMIRATES
AE=AED
# UNITED KINGDOM
GB=GBP
# UNITED STATES
US=USD
# UNITED STATES MINOR OUTLYING ISLANDS
UM=USD
# URUGUAY
UY=UYU
# UZBEKISTAN
UZ=UZS
# VANUATU
VU=VUV
# VENEZUELA
VE=VEB;2008-01-01-04-00-00;VEF
# VIET NAM
VN=VND
# VIRGIN ISLANDS, BRITISH
VG=USD
# VIRGIN ISLANDS, U.S.
VI=USD
# WALLIS AND FUTUNA
WF=XPF
# WESTERN SAHARA
EH=MAD
# YEMEN
YE=YER
# ZAMBIA
ZM=ZMK
# ZIMBABWE
ZW=ZWL
# List of currencies with 0, 1, OR 3 decimals for minor units, or where there
# are no minor units defined. All others use 2 decimals.
minor0=\
    ADP-BEF-BIF-BYB-BYR-CLF-CLP-DJF-ESP-GNF-\
    GRD-ISK-ITL-JPY-KMF-KRW-LUF-MGF-PYG-PTE-RWF-\
    TPE-TRL-VUV-XAF-XOF-XPF
minor1=
minor3=\
    BHD-IQD-JOD-KWD-LYD-OMR-TND
minorUndefined=\
    XAG-XAU-XBA-XBB-XBC-XBD-XDR-XFO-XFU-XPD-\
    XPT-XSU-XTS-XUA-XXX

5.编译结果

编译成功后会看到以下消息：

至于虚拟机的特性和源码分析等,会在后面的博客陆续进行讲解,敬请期待!