doc/html/user-guide/compiler-and-linker-options.html

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  81 CLASS="CHAPTER"
  82 ><H1
  83 ><A
  84 NAME="COMPILER-AND-LINKER-OPTIONS">Chapter 26. Compiler and Linker Options</H1
  85 ><DIV
  86 CLASS="TOC"
  87 ><DL
  88 ><DT
  89 ><B
  90 >Table of Contents</B
  91 ></DT
  92 ><DT
  93 ><A
  94 HREF="compiler-and-linker-options.html#COMPILING-C-APP"
  95 >Compiling a C Application</A
  96 ></DT
  97 ><DT
  98 ><A
  99 HREF="compiling-cpp-app.html"
 100 >Compiling a C++ Application</A
 101 ></DT
 102 ></DL
 103 ></DIV
 104 ><P
 105 ><SPAN
 106 CLASS="PRODUCTNAME"
 107 >eCos</SPAN
 108 > is built using
 109       the GNU C and C++ compilers. <SPAN
 110 CLASS="PRODUCTNAME"
 111 >eCos</SPAN
 112 > relies on certain features of these
 113       tools such as constructor priority ordering and selective linking
 114       which are not part of other toolchains.
 115     </P
 116 ><P
 117 >Some <SPAN
 118 CLASS="APPLICATION"
 119 >GCC</SPAN
 120 > options are required for <SPAN
 121 CLASS="PRODUCTNAME"
 122 >eCos</SPAN
 123 >,
 124 and others can be useful. This chapter gives a brief description
 125 of the required options as well as some recommended <SPAN
 126 CLASS="PRODUCTNAME"
 127 >eCos</SPAN
 128 >-specific options.
 129 All other <SPAN
 130 CLASS="APPLICATION"
 131 >GCC</SPAN
 132 > options (described in the <SPAN
 133 CLASS="APPLICATION"
 134 >GCC</SPAN
 135 > manuals)
 136 are available. </P
 137 ><DIV
 138 CLASS="SECT1"
 139 ><H1
 140 CLASS="SECT1"
 141 ><A
 142 NAME="COMPILING-C-APP">Compiling a C Application</H1
 143 ><P
 144 >The following command lines demonstrate the
 145           <SPAN
 146 CLASS="emphasis"
 147 ><I
 148 CLASS="EMPHASIS"
 149 >minimum</I
 150 ></SPAN
 151 > set of options required to
 152           compile and link an <SPAN
 153 CLASS="PRODUCTNAME"
 154 >eCos</SPAN
 155 > program written in C. </P
 156 ><DIV
 157 CLASS="NOTE"
 158 ><BLOCKQUOTE
 159 CLASS="NOTE"
 160 ><P
 161 ><B
 162 >Note: </B
 163 >Remember that when this manual shows
 164             <B
 165 CLASS="COMMAND"
 166 ><TT
 167 CLASS="REPLACEABLE"
 168 ><I
 169 >TARGET-</I
 170 ></TT
 171 >gcc</B
 172 >
 173             you should use the full name of the cross compiler,
 174             e.g. <B
 175 CLASS="COMMAND"
 176 >i386-elf-gcc</B
 177 >,
 178             <B
 179 CLASS="COMMAND"
 180 >arm-elf-gcc</B
 181 >, or
 182             <B
 183 CLASS="COMMAND"
 184 >sh-elf-gcc</B
 185 >. When compiling for the
 186             synthetic Linux target, use the native
 187             <B
 188 CLASS="COMMAND"
 189 >gcc</B
 190 > which must have the features
 191             required by <SPAN
 192 CLASS="PRODUCTNAME"
 193 >eCos</SPAN
 194 >.</P
 195 ></BLOCKQUOTE
 196 ></DIV
 197 ><TABLE
 198 BORDER="5"
 199 BGCOLOR="#E0E0F0"
 200 WIDTH="70%"
 201 ><TR
 202 ><TD
 203 ><PRE
 204 CLASS="SCREEN"
 205 >$ <TT
 206 CLASS="REPLACEABLE"
 207 ><I
 208 >TARGET-</I
 209 ></TT
 210 >gcc -c  -I<SPAN
 211 CLASS="emphasis"
 212 ><I
 213 CLASS="EMPHASIS"
 214 >INSTALL_DIR</I
 215 ></SPAN
 216 >/include file.c
 217 $ <TT
 218 CLASS="REPLACEABLE"
 219 ><I
 220 >TARGET-</I
 221 ></TT
 222 >gcc -o program file.o -L<SPAN
 223 CLASS="emphasis"
 224 ><I
 225 CLASS="EMPHASIS"
 226 >INSTALL_DIR</I
 227 ></SPAN
 228 >/lib -Ttarget.ld -nostdlib</PRE
 229 ></TD
 230 ></TR
 231 ></TABLE
 232 ><DIV
 233 CLASS="NOTE"
 234 ><BLOCKQUOTE
 235 CLASS="NOTE"
 236 ><P
 237 ><B
 238 >Note: </B
 239 >Certain targets may require extra options, for example
 240             the SPARClite architectures require the option
 241             <TT
 242 CLASS="OPTION"
 243 >-mcpu=sparclite</TT
 244 >. Examine the
 245             <TT
 246 CLASS="FILENAME"
 247 ><TT
 248 CLASS="REPLACEABLE"
 249 ><I
 250 >BASE_DIR</I
 251 ></TT
 252 >/examples/Makefile</TT
 253 >
 254             or the &#8220;Global compiler flags&#8221; option
 255             (CYGBLD_GLOBAL_CFLAGS) in your generated
 256             <SPAN
 257 CLASS="PRODUCTNAME"
 258 >eCos</SPAN
 259 > configuration) to see if any extra options are
 260             required, and if so, what they are. </P
 261 ><P
 262 >The following command lines use some other options
 263             which are recommended because they use the
 264         selective linking feature:</P
 265 ><TABLE
 266 BORDER="5"
 267 BGCOLOR="#E0E0F0"
 268 WIDTH="70%"
 269 ><TR
 270 ><TD
 271 ><PRE
 272 CLASS="SCREEN"
 273 >$ <TT
 274 CLASS="REPLACEABLE"
 275 ><I
 276 >TARGET-</I
 277 ></TT
 278 >gcc -c  -I<TT
 279 CLASS="REPLACEABLE"
 280 ><I
 281 >INSTALL_DIR</I
 282 ></TT
 283 >/include -I. -ffunction-sections -fdata-sections -g -O2 file.c
 284 $ <TT
 285 CLASS="REPLACEABLE"
 286 ><I
 287 >TARGET-</I
 288 ></TT
 289 >gcc -o program file.o -ffunction-sections -fdata-sections -Wl,--gc-sections -g -O2 \
 290           -L<TT
 291 CLASS="REPLACEABLE"
 292 ><I
 293 >INSTALL_DIR</I
 294 ></TT
 295 >/lib -Ttarget.ld -nostdlib</PRE
 296 ></TD
 297 ></TR
 298 ></TABLE
 299 ></BLOCKQUOTE
 300 ></DIV
 301 ></DIV
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