Don't include glibc symbol versions in libgcc.
Replace mips delay slot patch with upstream fix. Backport gcc typo fix from cvs to fix powerpc builds with newer binutils.
This commit is contained in:
Manuel Novoa III
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e29aaa1c6c
@ -288,7 +288,7 @@ diff -urN gcc-3.4.1-dist/gcc/config/t-linux-uclibc gcc-3.4.1/gcc/config/t-linux-
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+
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+# Override t-slibgcc-elf-ver to export some libgcc symbols with
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+# the symbol versions that glibc used.
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+SHLIB_MAPFILES += $(srcdir)/config/libgcc-glibc.ver
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+#SHLIB_MAPFILES += $(srcdir)/config/libgcc-glibc.ver
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+
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+# Use unwind-dw2-fde
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+LIB2ADDEH = $(srcdir)/unwind-dw2.c $(srcdir)/unwind-dw2-fde.c \
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@ -1,46 +0,0 @@
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http://www.linux-mips.org/archives/linux-mips/2004-09/msg00000.html
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Atsushi Nemoto <anemo@mba.ocn.ne.jp> writes:
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>/ Is this a get_user's problem or gcc's?/
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The latter. gcc is putting the empty asm:
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__asm__ ("":"=r" (__gu_val));
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into the delay slot of the call.
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Part of the problem is that gcc estimates the length of an asm to be the
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number of instruction separators + 1. This means that it estimates the
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asm above to be one instruction long, which is perhaps a little silly
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for an empty string.
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But the real problem is that gcc should never trust this estimate anyway,
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since each "instruction" could obviously be a multi-instruction macro.
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gcc should certainly never put asms into delay slots.
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FWIW, I don't think the bug is specific to 3.3 or 3.4. It could
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probably trigger for other gcc versions too. It is highly dependent
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on scheduling though.
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The attached 3.4.x patch fixes the problem there, but if you want to work
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around it for old versions, just avoid using empty asms if you can,
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or make them volatile if you can't.
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Of course, the problem isn't confined to empty asms. If you have an asm
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with a single, multi-instruction macro, gcc might try putting that in a
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delay slot too. You should at least get an assembler warning in that case.
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Richard
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--- gcc-3.4.1/gcc/config/mips/mips.md-orig 2004-09-02 10:38:36.000000000 -0500
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+++ gcc-3.4.1/gcc/config/mips/mips.md 2004-09-02 10:38:42.000000000 -0500
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@@ -251,7 +251,7 @@
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;; Can the instruction be put into a delay slot?
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(define_attr "can_delay" "no,yes"
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- (if_then_else (and (eq_attr "type" "!branch,call,jump")
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+ (if_then_else (and (eq_attr "type" "!branch,call,jump,multi")
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(and (eq_attr "hazard" "none")
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(eq_attr "single_insn" "yes")))
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(const_string "yes")
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102
sources/gcc/3.4.2/400-mips-pr17565.patch
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102
sources/gcc/3.4.2/400-mips-pr17565.patch
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@ -0,0 +1,102 @@
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[committed] Fix target/17565: asms in delay slots
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* From: Richard Sandiford <rsandifo at redhat dot com>
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* To: gcc-patches at gcc dot gnu dot org
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* Date: Mon, 20 Sep 2004 07:55:58 +0100
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* Subject: [committed] Fix target/17565: asms in delay slots
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The MIPS port was allowing asms to be put into delay slots if the
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compiler guesses they are only one instruction long. This is wrong
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because of the possibility of it containing macros.
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The problem can be reproduced as an assembler warning
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in the following testcase:
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int foo (int n)
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{
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register int k asm ("$16") = n;
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if (k > 0)
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{
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bar ();
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asm ("li %0,0x12345678" : "=r" (k));
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}
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return k;
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}
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because the multi-instruction asm statement goes into the delay
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slot of the call to bar().
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This is reduced from a much more serious linux problem. Linux is fond
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of using empty asm statements, and since gcc estimates empty asms to be
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one instruction long, they too might be put into delay slots. This
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actually has the effect of putting the following instruction into the
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delay slot instead. Since there's no assembler warning, the problem was
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only detected as a run-time failure.
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The fix is simple: set the asm value of "can_delay" to "no".
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Tested on mipsisa64-elf, applied to mainline.
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This problem goes back to at least 2.95, so it isn't technically a
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regression. On the other hand, it's the kind of bug that could trigger
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for different types of code in different releases, so I'm sure there's
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a testcase that fails (say) in 3.4 and not in 2.95. Will probably ask
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Mark for permission to backport to 3.4.
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Richard
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PR target/17565
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* config/mips/mips.md (define_asm_attributes): Set can_delay to no.
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testsuite/
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* gcc.target/mips/asm-1.c: New test.
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Index: config/mips/mips.md
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===================================================================
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RCS file: /cvs/gcc/gcc/gcc/config/mips/mips.md,v
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retrieving revision 1.306
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diff -c -p -F^\([(a-zA-Z0-9_]\|#define\) -r1.306 mips.md
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*** gcc/gcc/config/mips/mips.md 13 Sep 2004 19:32:05 -0000 1.306
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--- gcc/gcc/config/mips/mips.md 20 Sep 2004 06:52:31 -0000
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*************** (define_attr "may_clobber_hilo" "no,yes"
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*** 266,272 ****
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;; Describe a user's asm statement.
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(define_asm_attributes
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! [(set_attr "type" "multi")])
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;; .........................
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;;
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--- 266,273 ----
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;; Describe a user's asm statement.
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(define_asm_attributes
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! [(set_attr "type" "multi")
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! (set_attr "can_delay" "no")])
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;; .........................
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;;
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Index: testsuite/gcc.target/mips/asm-1.c
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===================================================================
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RCS file: testsuite/gcc.target/mips/asm-1.c
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diff -N testsuite/gcc.target/mips/asm-1.c
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*** gcc/gcc/testsuite/gcc.target/mips/asm-1.c 1 Jan 1970 00:00:00 -0000
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--- gcc/gcc/testsuite/gcc.target/mips/asm-1.c 20 Sep 2004 06:52:31 -0000
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***************
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*** 0 ****
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--- 1,14 ----
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+ /* PR target/17565. GCC used to put the asm into the delay slot
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+ of the call. */
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+ /* { dg-do assemble } */
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+ /* { dg-options "-O" } */
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+ int foo (int n)
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+ {
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+ register int k asm ("$16") = n;
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+ if (k > 0)
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+ {
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+ bar ();
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+ asm ("li %0,0x12345678" : "=r" (k));
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+ }
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+ return k;
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+ }
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20
sources/gcc/3.4.2/401-ppc-eabi-typo.patch
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20
sources/gcc/3.4.2/401-ppc-eabi-typo.patch
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@ -0,0 +1,20 @@
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revision 1.12
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date: 2004/07/16 15:13:40; author: segher; state: Exp; lines: +1 -1
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* config/rs6000/eabi.asm (__eabi_convert): Fix typo (cmpi vs. cmpwi).
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Index: gcc/config/rs6000/eabi.asm
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===================================================================
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RCS file: /cvs/gcc/gcc/gcc/config/rs6000/eabi.asm,v
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retrieving revision 1.11
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retrieving revision 1.12
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diff -u -b -B -w -p -r1.11 -r1.12
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--- gcc/gcc/config/rs6000/eabi.asm 20 Sep 2002 23:46:58 -0000 1.11
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+++ gcc/gcc/config/rs6000/eabi.asm 16 Jul 2004 15:13:40 -0000 1.12
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@@ -252,7 +252,7 @@ FUNC_START(__eabi_convert)
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.Lcvt:
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lwzu 6,4(3) /* pointer to convert */
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- cmpi 0,6,0
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+ cmpwi 0,6,0
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beq- .Lcvt2 /* if pointer is null, don't convert */
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add 6,6,12 /* convert pointer */
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