1 | <sect2><title> </title><para> </para></sect2>
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2 |
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3 | <sect2>
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4 | <title>Re-installation of GCC</title>
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5 |
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6 | <para>The tools required to test GCC and Binutils are installed now
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7 | (Expect, TCL and DejaGNU). We can continue on rebuilding GCC and Binutils,
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8 | link them against the new Glibc, and test them properly. One thing to note,
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9 | however, is that these test suites are highly dependent on the features
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10 | supported by your host distribution. Most notably, a host distribution
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11 | which does not properly support the devpts filesystem will cause most of
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12 | these tests to fail.</para>
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13 |
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14 | <para>Unpack all three GCC tarballs in one and the same working directory.
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15 | They will all unfold into a single <filename>gcc-&gcc-version;/</filename>
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16 | subdir.</para>
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17 |
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18 | <para>First correct one problem and make an essential adjustment:</para>
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19 |
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20 | <para><screen><userinput>patch -Np1 -i ../gcc-&gcc-version;-no_fixincludes-2.patch
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21 | patch -Np1 -i ../gcc-&gcc-specs-version;.patch</userinput></screen></para>
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22 |
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23 | <para>The first patch disables the GCC "fixincludes" script. We mentioned this
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24 | briefly earlier, but a slightly more in-depth explanation of the fixincludes
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25 | process is warranted here. Under normal circumstances, the GCC fixincludes
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26 | script scans your system for header files that need to be fixed. It might find
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27 | that the Glibc header files on your host system need to be fixed, fix them and
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28 | put them in the GCC private include directory. Then, later on in Chapter 6,
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29 | after we've installed the newer Glibc, this private include directory would be
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30 | searched before the system include directory, resulting in GCC finding the
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31 | fixed headers from the host system, which would most likely not match the Glibc
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32 | version actually used for the LFS system.</para>
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33 |
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34 | <para>The last patch changes GCC's default location of the dynamic linker
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35 | (ld). Patching now rather than adjusting the specs file after installation
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36 | ensures that our new dynamic linker gets used during the actual build of GCC.
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37 | That is, all the final (and temporary) binaries created during the build will
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38 | link against the new Glibc.</para>
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39 |
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40 | <para>Create a separate build directory again:</para>
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41 |
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42 | <para><screen><userinput>mkdir ../gcc-build
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43 | cd ../gcc-build</userinput></screen></para>
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44 |
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45 | <para>Before starting to build GCC, remember to unset any environment
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46 | variables that override the default optimization flags.</para>
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47 |
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48 | <para>Now prepare GCC to be compiled:</para>
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49 |
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50 | <para><screen><userinput>../gcc-&gcc-version;/configure --prefix=/tools \
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51 | --with-local-prefix=/tools \
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52 | --enable-clocale=gnu --enable-shared \
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53 | --enable-threads=posix --enable-__cxa_atexit \
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54 | --enable-languages=c,c++</userinput></screen></para>
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55 |
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56 | <para>Compile the package:</para>
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57 |
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58 | <para><screen><userinput>make</userinput></screen></para>
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59 | <para>There is no need to use the <userinput>bootstrap</userinput> target now,
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60 | as the compiler we're using to compile this GCC has been built from the exact
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61 | same sources.</para>
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62 |
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63 | <para>Test the results:</para>
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64 |
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65 | <para><screen><userinput>make -k check</userinput></screen></para>
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66 |
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67 | <para>The <userinput>-k</userinput> flag is used to make the test suite run
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68 | through to completion and not stop at the first failure. The GCC test suite is
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69 | very comprehensive and is almost guaranteed to generate a few failures. To get
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70 | a summary of the test suite results, run this:</para>
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71 |
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72 | <para><screen><userinput>../gcc-&gcc-version;/contrib/test_summary | less</userinput></screen></para>
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73 |
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74 | <para>You can compare your results to those posted to the gcc-testresults
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75 | mailing list for similar configurations to your own. For an example of how
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76 | current GCC-3.3.1 should look on i686-pc-linux-gnu, see
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77 | <ulink url="http://gcc.gnu.org/ml/gcc-testresults/2003-08/msg01612.html"/>.</para>
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78 |
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79 | <para>Note that the results contain:</para>
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80 |
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81 | <screen>* 1 XPASS (unexpected pass) for g++
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82 | * 1 FAIL for g++
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83 | * 2 FAIL for gcc
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84 | * 26 XPASS's for libstdc++</screen>
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85 |
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86 | <para>The unexpected pass for g++ is due to the use of
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87 | <userinput>--enable-__cxa_atexit</userinput>. Apparently not all platforms
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88 | supported by GCC have support for "__cxa_atexit" in their C libraries, so this
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89 | test is not always expected to pass.</para>
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90 |
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91 | <para>The 26 unexpected passes for libstdc++ are due to the use of
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92 | <userinput>--enable-clocale=gnu</userinput>, which is the correct choice on
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93 | Glibc-based systems of versions 2.2.5 and above. The underlying locale support
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94 | in the GNU C library is superior to that of the otherwise selected "generic"
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95 | model (which may be applicable if for instance you were using Newlibc, Sun-libc
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96 | or whatever libc). The libstdc++ test suite is apparently expecting the
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97 | "generic" model, hence those tests are not always expected to pass.</para>
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98 |
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99 | <para>And finally install the package:</para>
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100 |
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101 | <para><screen><userinput>make install</userinput></screen></para>
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102 |
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103 | </sect2>
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104 |
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