1 | # |
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2 | # $Id$ |
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3 | # |
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4 | |
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5 | make/README |
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6 | |
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7 | This file describes the layout and conventions of the application |
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8 | makefile support for RTEMS applications. Internally, RTEMS uses |
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9 | GNU-style autoconf/automake Makefiles as much as possible to |
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10 | ease integration with other GNU tools. |
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11 | |
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12 | All of these "make" trees are substantially similar; however this |
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13 | file documents the current state of the RTEMS Application Makefile |
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14 | support. |
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15 | |
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16 | This make tree is based on a build system originally developed |
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17 | to simplify porting projects between various OS's. The primary |
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18 | goals were: |
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19 | |
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20 | . simple *and* customizable individual makefiles |
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21 | |
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22 | . use widely available GNU make. There is no pre-processing or |
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23 | automatic generation of Makefiles. |
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24 | |
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25 | . Same makefiles work on *many* host OS's due to portability |
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26 | of GNU make and the host OS config files. |
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27 | |
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28 | . Support for different compilers and operating systems |
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29 | on a per-user basis. Using the same sources (including |
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30 | Makefiles) one developer can develop and test under SVR4, |
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31 | another under 4.x, another under HPUX. |
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32 | |
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33 | . Builtin support for compiling "variants" such as debug |
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34 | versions. These variants can be built |
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35 | recursively. |
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36 | |
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37 | . Control of system dependencies. "hidden" dependencies on |
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38 | environment variables (such as PATH) |
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39 | have been removed whenever possible. No matter what your |
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40 | PATH variable is set to, you should get the same thing |
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41 | when you 'make' as everyone else on the project. |
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42 | |
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43 | This Makefile system has evolved into its present form and as it |
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44 | exists in RTEMS today, its sole goal is to build RTEMS applications. |
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45 | The use of these Makefiles hides the complexity of producing |
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46 | executables for a wide variety of embedded CPU families and target |
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47 | BSPs. Switching between RTEMS BSPs is accomplished via setting |
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48 | the environment variable "RTEMS_MAKEFILE_PATH." |
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49 | |
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50 | This description attempts to cover all aspects of the Makefile tree. Most |
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51 | of what is described here is maintained automatically by the configuration |
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52 | files. |
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53 | |
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54 | The example makefiles in make/Templates should be used as a starting |
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55 | point for new directories. |
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56 | |
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57 | There are 2 main types of Makefile: |
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58 | |
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59 | directory and leaf. |
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60 | |
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61 | Directory Makefiles |
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62 | ------------------- |
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63 | |
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64 | A Makefile in a source directory with sub-directories is called a |
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65 | "directory" Makefile. |
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66 | |
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67 | Directory Makefile's are simply responsible for acting as "middle-men" |
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68 | and recursing into their sub-directories and propagating the make. |
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69 | |
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70 | For example, directory src/bin will contain only a Makefile and |
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71 | sub-directories. No actual source code will reside in the directory. |
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72 | The following commands: |
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73 | |
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74 | $ cd src/bin |
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75 | $ make all |
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76 | |
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77 | would descend into all the subdirectories of 'src/bin' and recursively |
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78 | perform a 'make all'. |
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79 | |
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80 | A 'make debug' will recurse thru sub-directories as a debug build. |
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81 | |
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82 | A template directory Makefile which should work in almost all |
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83 | cases is in make/Templates/Makefile.dir |
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84 | |
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85 | |
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86 | Leaf Makefiles |
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87 | -------------- |
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88 | |
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89 | Source directories that contain source code for libraries or |
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90 | programs use a "leaf" Makefile. |
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91 | |
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92 | These makefiles contain the rules necessary to build programs |
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93 | (or libraries). |
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94 | |
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95 | A template leaf Makefile is in Templates/Makefile.leaf . A template |
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96 | leaf Makefile for building libraries is in Templates/Makefile.lib . |
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97 | |
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98 | |
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99 | NOTE: To simplify nested makefile's and source maintenance, we disallow |
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100 | combining source and directories (that make(1) would be expected to |
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101 | recurse into) in one source directory. Ie., a directory in the source |
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102 | tree may contain EITHER source files OR recursive sub directories, but NOT |
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103 | both. This assumption is generally shared with GNU automake. |
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104 | |
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105 | Variants (where objects go) |
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106 | --------------------------- |
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107 | |
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108 | All binary targets are placed in a sub-directory whose name is (for |
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109 | example): |
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110 | |
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111 | o-optimize/ -- optimized binaries |
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112 | o-debug/ -- debug binaries |
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113 | |
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114 | Using the template Makefiles, this will all happen automatically. |
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115 | The contents of these directories are specific to a BSP. |
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116 | |
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117 | Within a Makefile, the ${ARCH} variable is set to o-optimize, |
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118 | o-debug, etc., as appropriate. |
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119 | |
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120 | HISTORICAL NOTE: Prior to version 4.5, the name of the sub-directory |
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121 | in which objects were placed included the BSP name. |
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122 | |
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123 | Typing 'make' will place objects in o-optimize. |
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124 | 'make debug' will place objects in o-debug. |
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125 | |
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126 | The debug targets are equivalent to 'all' except that |
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127 | CFLAGS and/or LDFLAGS are modified as per the compiler config file for |
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128 | debug and profile support. |
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129 | |
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130 | The targets debug etc., can be invoked recursively at |
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131 | the directory make level. So from the top of a tree, one could |
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132 | install a debug version of everything under that point by: |
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133 | |
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134 | $ cd src/lib |
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135 | $ gmake debug |
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136 | $ gmake install |
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137 | |
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138 | When building a command that is linked with a generated library, the |
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139 | appropriate version of the library will be linked in. |
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140 | |
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141 | For example, the following fragments link the normal, debug, or |
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142 | version of "libmine.a" as appropriate: |
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143 | |
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144 | LD_LIBS += $(LIBMINE) |
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145 | LIBMINE = ../libmine/${ARCH}/libmine.a |
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146 | |
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147 | ${ARCH}/pgm: $(LIBMINE) ${OBJS} |
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148 | $(make-exe) |
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149 | |
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150 | If we do 'gmake debug', then the library in |
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151 | ../libmine/o-debug/libmine.a will be linked in. If $(LIBMINE) |
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152 | might not exist (or might be out of date) at this point, we could add |
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153 | |
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154 | ${LIBMINE}: FORCEIT |
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155 | cd ../libmine; ${MAKE} ${VARIANT_VA} |
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156 | |
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157 | The above would generate the following command to build libmine.a: |
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158 | |
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159 | cd ../libmine; gmake debug |
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160 | |
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161 | The macro reference ${VARIANT_VA} converts ${ARCH} to the word 'debug' |
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162 | (in this example) and thus ensures the proper version of the library |
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163 | is built. |
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164 | |
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165 | |
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166 | Targets |
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167 | ------- |
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168 | |
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169 | All Makefile's support the following targets: |
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170 | |
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171 | all -- make "everything" |
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172 | install -- install "everything" |
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173 | |
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174 | The following targets are provided automatically by |
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175 | the included config files: |
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176 | |
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177 | clean -- delete all targets |
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178 | depend -- build a make dependency file |
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179 | "variant targets" -- special variants, see below |
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180 | |
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181 | |
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182 | All directory Makefiles automatically propagate all these targets. If |
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183 | you don't wish to support 'all' or 'install' in your source directory, |
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184 | you must leave the rules section empty, as the parent directory Makefile |
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185 | will attempt it on recursive make's. |
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186 | |
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187 | |
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188 | Configuration |
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189 | ------------- |
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190 | |
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191 | All the real work described here happens in file(s) included |
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192 | from your Makefile. |
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193 | |
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194 | All Makefiles include a customization file which is used to select |
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195 | compiler and host operating system. The environment variable |
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196 | RTEMS_MAKEFILE_PATH must point to the directory containing this file; eg: |
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197 | |
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198 | export RTEMS_MAKEFILE_PATH=/.../pc386/ |
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199 | |
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200 | All leaf Makefile's also include either 'make/leaf.cfg' (or |
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201 | 'make/lib.cfg' for building libraries). These config files provide |
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202 | default rules and set up the command macros as appropriate. |
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203 | |
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204 | All directory Makefiles include 'make/directory.cfg'. directory.cfg |
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205 | provides all the rules for recursing through sub directories. |
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206 | |
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207 | The Makefile templates already perform these include's. |
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208 | |
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209 | 'make/leaf.cfg' (or directory.cfg) in turn includes: |
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210 | |
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211 | a file specifying general purpose rules appropriate for |
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212 | both leaf and directory makefiles. |
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213 | ( make/main.cfg ) |
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214 | |
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215 | personality modules specified by the customization file for: |
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216 | compiler ( make/compilers/??.cfg ) |
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217 | |
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218 | |
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219 | generic rules file |
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220 | ------------------ |
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221 | |
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222 | [ make/main.cfg ] |
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223 | included by leaf.cfg or directory.cfg. |
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224 | |
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225 | This file contains some standard rules and variable assignments |
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226 | that all Makefiles need. |
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227 | |
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228 | It also includes the FORCEIT: pseudo target. |
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229 | |
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230 | |
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231 | OS config file for host machine |
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232 | ------------------------------- |
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233 | |
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234 | [ make/os/OS-NAME.cfg ] |
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235 | included by main.cfg |
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236 | |
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237 | Figures out the target architecture and specifies command names |
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238 | for the OS tools including RCS/CVS (but NOT for the compiler tools). |
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239 | |
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240 | |
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241 | Compiler configuration for the target |
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242 | ------------------------------------- |
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243 | |
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244 | [ compilers/COMPILER-NAME.cfg ] |
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245 | included by leaf.cfg |
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246 | |
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247 | Specifies the names of tools for compiling programs. |
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248 | Names in here should be fully qualified, and NOT depend on $PATH. |
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249 | |
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250 | Also specifies compiler flags to be used to generate optimized, |
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251 | debugging versions, as well as rules to compile |
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252 | assembly language and make makefile dependencies. |
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253 | |
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254 | |
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255 | Configuration Variables |
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256 | ----------------------- |
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257 | |
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258 | Variables you have to set in the environment or in your Makefile. |
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259 | Note: the RTEMS module files set RTEMS_ROOT and RTEMS_CUSTOM |
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260 | for you. |
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261 | |
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262 | Makefile Variables |
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263 | ------------------ |
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264 | |
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265 | RTEMS_BSP -- name of your 'bsp' eg: pc386, mvme136 |
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266 | |
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267 | RTEMS_CPU -- CPU architecture e.g.: i386, m68k |
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268 | |
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269 | RTEMS_CPU_FAMILY -- CPU model e.g.: i486dx, m68020 |
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270 | |
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271 | RTEMS_ROOT -- The root of your source tree. |
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272 | All other file names are derived from this. |
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273 | [ eg: % setenv RTEMS_ROOT $HOME/work/RTEMS ] |
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274 | |
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275 | RTEMS_CUSTOM -- name of your config files in make/custom |
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276 | Example: |
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277 | $(RTEMS_ROOT)/make/custom/$(RTEMS_BSP).cfg |
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278 | |
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279 | The value RTEMS_ROOT is used in the custom |
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280 | files to generate the make(1) variables: |
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281 | |
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282 | PROJECT_RELEASE |
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283 | PROJECT_BIN |
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284 | PROJECT_INCLUDE |
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285 | PROJECT_TOOLS |
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286 | |
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287 | etc., which are used within the make config files themselves. |
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288 | (The files in make/*.cfg try to avoid use of word RTEMS so |
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289 | they can be more easily shared by other projects) |
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290 | |
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291 | Preset variables |
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292 | ---------------- |
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293 | |
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294 | Aside from command names set by the OS and compiler config files, |
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295 | a number of MAKE variables are automatically set and maintained by |
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296 | the config files. |
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297 | |
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298 | PROJECT_RELEASE |
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299 | -- release/install directory |
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300 | [ $(PROJECT_ROOT) ] |
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301 | |
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302 | PROJECT_BIN |
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303 | -- directory for installed binaries |
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304 | [ $(PROJECT_ROOT)/bin ] |
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305 | |
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306 | PROJECT_TOOLS |
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307 | -- directory for build environment commands |
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308 | [ eg: $(PROJECT_ROOT)/build-tools ] |
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309 | |
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310 | ARCH -- target sub-directory for object code |
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311 | [ eg: o-optimize or o-debug ] |
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312 | |
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313 | VARIANTS -- full list of all possible values for $(ARCH); |
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314 | used mainly for 'make clean' |
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315 | [ eg: "o-optimize o-debug" ] |
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316 | |
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317 | VARIANT_VA -- Variant name. |
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318 | Normally "", but for 'make debug' it is "debug". |
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319 | |
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320 | see make/leaf.cfg for more info. |
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321 | |
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322 | |
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323 | Preset compilation variables |
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324 | ---------------------------- |
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325 | |
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326 | This is a list of some of the compilation variables. |
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327 | Refer to the compiler config files for the complete list. |
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328 | |
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329 | CFLAGS_OPTIMIZE_V -- value of optimize flag for compiler |
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330 | [ eg: -O ] |
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331 | |
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332 | CFLAGS_DEBUG_V -- value of debug flag for compiler |
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333 | [ eg: -g ] |
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334 | |
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335 | CFLAGS_DEBUG_OPTIMIZE_V |
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336 | -- optimize flag if compiling for debug |
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337 | [ eg: "" ] |
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338 | |
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339 | CFLAGS_DEBUG |
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340 | CFLAGS_OPTIMIZE -- current values for each depending |
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341 | on make variant. |
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342 | |
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343 | LDFLAGS_STATIC_LIBRARIES_V |
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344 | -- ld option for static libraries |
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345 | -Bstatic or -dy (svr4) |
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346 | |
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347 | LDFLAGS_SHARED_LIBRARIES_V |
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348 | -- ld option for dynamic libraries |
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349 | -Bdynamic or -dn (svr4) |
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350 | |
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351 | Makefile Variables |
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352 | ------------------ |
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353 | |
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354 | The following variables may be set in a typical Makefile. |
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355 | |
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356 | C_PIECES -- File names of your .c files without '.c' suffix. |
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357 | [ eg: C_PIECES=main funcs stuff ] |
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358 | |
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359 | CC_PIECES -- ditto, except for .cc files |
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360 | |
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361 | S_PIECES -- ditto, except for .S files. |
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362 | |
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363 | LIB -- target library name in leaf library makefiles. |
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364 | [ eg: LIB=${ARCH}/libmine.a ] |
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365 | |
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366 | H_FILES -- your .h files in this directory. |
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367 | [ eg: H_FILES=stuff.h extra.h ] |
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368 | |
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369 | DEFINES -- cc -D items. Included in CPPFLAGS. |
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370 | leaf Makefiles. |
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371 | [ eg: DEFINES += -DUNIX ] |
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372 | |
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373 | CPPFLAGS -- -I include directories. |
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374 | leaf Makefiles. |
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375 | [ eg: CPPFLAGS += -I../include ] |
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376 | |
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377 | LD_PATHS -- arguments to -L for ld. |
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378 | Will be prefixed with '-L' or '-L ' as appropriate |
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379 | and included in LDFLAGS. |
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380 | |
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381 | LDFLAGS -- -L arguments to ld; more may be ADDed. |
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382 | |
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383 | LD_LIBS -- libraries to be linked in. |
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384 | [ eg: LDLIBS += ../libfoo/${ARCH}/libfoo.a ] |
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385 | |
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386 | XCFLAGS -- "extra" CFLAGS for special needs. Pre-pended |
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387 | to CFLAGS. |
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388 | Not set or used by Makefiles. |
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389 | Can be set on command line to pass extra flags |
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390 | to the compiler. |
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391 | |
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392 | XCPPFLAGS -- ditto for CPPFLAGS |
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393 | Can be set on command line to pass extra flags |
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394 | to the preprocessor. |
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395 | |
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396 | XCCPPFLAGS -- same as XCPPFLAGS for C++. |
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397 | |
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398 | XCCFLAGS -- same as XCFLAGS for C++. |
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399 | |
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400 | SUBDIRS -- list of sub directories for make recursion. |
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401 | directory Makefiles only. |
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402 | [ eg: SUBDIRS=cpu bsp ] |
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403 | |
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404 | CLEAN_ADDITIONS |
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405 | -- list of files or directories that should |
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406 | be deleted by 'make clean' |
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407 | [ eg: CLEAN_ADDITIONS += y.tab.c ] |
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408 | |
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409 | See 'leaf.cfg' for the 'clean:' rule and its |
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410 | default deletions. |
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411 | |
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412 | CLOBBER_ADDITIONS |
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413 | -- list of files or directories that should |
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414 | be deleted by 'make clobber' |
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415 | Since 'make clobber' includes 'make clean', |
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416 | you don't need to duplicate items in both. |
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417 | |
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418 | Command names |
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419 | ------------- |
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420 | |
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421 | The following commands should only be called |
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422 | as make variables: |
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423 | |
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424 | MAKE,INSTALL,INSTALL_VARIANT,SHELL |
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425 | |
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426 | ECHO,CAT,CP,MV,LN,MKDIR,CHMOD |
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427 | |
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428 | SED |
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429 | |
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430 | CC,CPP,AS,AR,LD,NM,SIZE,RANLIB,MKLIB, |
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431 | YACC,LEX,LINT,CTAGS,ETAGS |
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432 | |
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433 | In addition, the following commands specifically support |
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434 | the installation of libraries, executables, header files, |
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435 | and other things that need to be installed: |
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436 | |
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437 | INSTALL_CHANGE - install a file only if the source |
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438 | file is actually different than |
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439 | the installed copy or if there is |
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440 | no installed copy. USAGE: |
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441 | |
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442 | usage: install-if-change [ -vmV ] file [ file ... ] dest-directory-or-file |
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443 | -v -- verbose |
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444 | -V suffix -- suffix to append to targets (before any . suffix) |
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445 | eg: -V _g would change 'foo' to 'foo_g' and |
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446 | 'libfoo.a' to 'libfoo_g.a' |
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447 | -m mode -- mode for new file(s) |
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448 | |
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449 | INSTALL_VARIANT - installs the built file using the |
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450 | proper variant suffix (e.g. _g |
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451 | for debug turns libmine.a into libmine_g.a) |
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452 | This is implemented as a macro that |
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453 | invokes install-if-change with the |
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454 | appropriate -V argument setting. |
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455 | |
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456 | Special Directory Makefile Targets |
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457 | ---------------------------------- |
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458 | |
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459 | all_WRAPUP |
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460 | clean_WRAPUP |
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461 | install_WRAPUP |
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462 | clean_WRAPUP |
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463 | clobber_WRAPUP |
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464 | depend_WRAPUP |
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465 | -- Specify additional commands for recursive |
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466 | (directory level) targets. |
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467 | |
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468 | This is handy in certain cases where you need |
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469 | to do bit of work *after* a recursive make. |
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470 | |
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471 | make/Templates |
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472 | -------------- |
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473 | |
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474 | This directory contains Makefile and source file templates that |
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475 | should help in creating or converting makefiles. |
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476 | |
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477 | Makefile.leaf |
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478 | Template leaf Makefiles. |
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479 | |
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480 | Makefile.lib |
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481 | Template leaf library Makefiles. |
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482 | |
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483 | Makefile.dir |
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484 | Template "directory" makefile. |
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485 | |
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486 | |
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487 | |
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488 | |
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