54 lines
1.9 KiB
Diff
54 lines
1.9 KiB
Diff
When compiling a project using -frepo, .rpo files are written alongside
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the .o file, the symbols either have O or C against them. During final linking,
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the objects can be recompiled with some of the entries tweaked/chosen by the
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tlink.c code (visible with TLINK_VERBOSE=3), it does this by changing O -> C
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in the .rpo files.
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My tests showed that init_repo (cp/repo.c) was correctly calling
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IDENTIFIER_REPO_CHOSEN against the right identifers and setting the
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chosen bit.
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By the time finish_repo() or emit_repo_p() were called, the pointer returned
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by get_identifier() for the symbol marked during init_repo had changed and
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the chosen bit was no longer set. This lead to linking bugs like:
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collect: relinking
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collect2: error: '_ZNK6sudoku5ClearINS_8SequenceEEclERS1_' was assigned to 'board.rpo', but was not defined during recompilation, or vice versa
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The problem is that the garbage collection is getting called before
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finish_repo() is called and ggc_protect_identifiers is set to false
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so the identifiers are not preserved. They are recreated but the
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chosen bits get wiped out which is why the pointer changes and the
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chosen bit is not set.
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The fix is to change ggc_protect_identifiers *after* the finish_repo
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calls are made.
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Reproduction is tricky since you need to trigger the garbage collector at
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just the right moment.
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RP 2013/10/9
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[YOCTO #5133]
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Upstream-Status: Pending
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Index: gcc-4.8.1/gcc/toplev.c
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===================================================================
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--- gcc-4.8.1.orig/gcc/toplev.c 2013-03-28 08:29:51.000000000 +0000
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+++ gcc-4.8.1/gcc/toplev.c 2013-10-09 20:27:17.089228023 +0000
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@@ -551,11 +551,11 @@
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if (flag_syntax_only || flag_wpa)
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return;
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- ggc_protect_identifiers = false;
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-
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/* This must also call finalize_compilation_unit. */
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lang_hooks.decls.final_write_globals ();
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+ ggc_protect_identifiers = false;
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+
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if (seen_error ())
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return;
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