patches/gcc/4.3.6/110-trampolinewarn.patch
author "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Tue Dec 13 23:32:39 2011 +0100 (2011-12-13)
branch1.13
changeset 2847 c0bf2319af08
parent 2124 5dd0b83ae528
permissions -rw-r--r--
scripts: fix dumping execution backtrace

Dumping the backtrace has been broken since changeset #652e56d6d35a:
scripts: execute each steps in a subshell

We can spawn sub-sub-shells in some cases.

The way the fault handler works is to dump the backtrace, but to avoid
printing it once for every sub-shell (which could get quite confusing),
it simply exits when it detects that it is being run in a sub-shell,
leaving to the top-level shell the work to dump the backtrace.

Because each step is executed in its own sub-shell, the variable arrays
that contain the step name, the source file and line number, are lost
when exiting the per-step sub-shell.

Hence, the backtrace is currently limited to printing only the top-level
main procedure of the shell.

Fix this thus:
- when dumping the bckatraces for the steps & the functions, remember
it was dumped, and only dump it if it was not already dumped
- at the top-level shell, print the hints

Also, rename the top-level step label.

Reported-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
(transplanted from 4193d6e6a17430a177fa88c287879c2c35e319f3)
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Original patch from: ../4.3.2/110-trampolinewarn.patch
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-= BEGIN original header =-
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Original patch from gentoo: gentoo/src/patchsets/gcc/4.3.1/gentoo/00_all_gcc-trampolinewarn.patch
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	This trivial patch causes gcc to emit a warning whenever
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	it generates a trampoline.  These are otherwise hard to
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	locate.  It is rigged to default ON - to have it default
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	to OFF remove the text 'Init(1)' from the common.opt
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	patch, leaving just 'Common Var(warn_trampolines)'.
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	Kevin F. Quinn <kevquinn@gentoo.org> 17 Jan 2006
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-= END original header =-
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diff -durN gcc-4.3.3.orig/gcc/builtins.c gcc-4.3.3/gcc/builtins.c
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--- gcc-4.3.3.orig/gcc/builtins.c	2008-08-19 18:37:13.000000000 +0200
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+++ gcc-4.3.3/gcc/builtins.c	2009-01-27 22:19:12.000000000 +0100
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@@ -5662,6 +5662,9 @@
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   trampolines_created = 1;
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   INITIALIZE_TRAMPOLINE (r_tramp, r_func, r_chain);
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+  if (warn_trampolines)
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+    warning (OPT_Wtrampolines, "generating trampoline in object (requires executable stack)");
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+
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   return const0_rtx;
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 }
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diff -durN gcc-4.3.3.orig/gcc/common.opt gcc-4.3.3/gcc/common.opt
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--- gcc-4.3.3.orig/gcc/common.opt	2008-01-22 15:11:44.000000000 +0100
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+++ gcc-4.3.3/gcc/common.opt	2009-01-27 22:19:12.000000000 +0100
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@@ -182,6 +182,10 @@
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 Common Var(warn_system_headers) Warning
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 Do not suppress warnings from system headers
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+Wtrampolines
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+Common Var(warn_trampolines) Init(1)
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+Warn whenever a trampoline is generated
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+
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 Wuninitialized
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 Common Var(warn_uninitialized) Warning
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 Warn about uninitialized automatic variables