[Bug target/65771] New: [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[Bug target/65771] New: [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[doko at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

            Bug ID: 65771
           Summary: [5 Regression] ICE (in loc_list_from_tree, at
                    dwarf2out.c:14964) on arm-linux-gnueabihf
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: doko at gcc dot gnu.org

seen with r222064 on arm-linux-gnueabihf, building the nauty package.

$ cat traces.i
typedef struct {
  int tolevel;
  int tgtsize;
} TracesSpine;
__thread TracesSpine a[];
b;
fn1() { int c = a[b].tgtsize; }


$ gcc -c -g -O2 traces.i
traces.i:6:1: warning: data definition has no type or storage class
 b;
 ^
traces.i:6:1: warning: type defaults to 'int' in declaration of 'b'
[-Wimplicit-int]
traces.i:7:1: warning: return type defaults to 'int' [-Wimplicit-int]
 fn1() { int c = a[b].tgtsize; }
 ^
traces.i:5:22: warning: array 'a' assumed to have one element
 __thread TracesSpine a[];
                      ^
traces.i: In function 'fn1':
traces.i:7:1: internal compiler error: in loc_list_from_tree, at
dwarf2out.c:14964
 fn1() { int c = a[b].tgtsize; }
 ^
0x2cd239 loc_list_from_tree
        ../../src/gcc/dwarf2out.c:14964
0x2cc037 loc_list_from_tree
        ../../src/gcc/dwarf2out.c:14663
0x2cc54d loc_list_from_tree
        ../../src/gcc/dwarf2out.c:14870
0x2cbee7 loc_list_from_tree
        ../../src/gcc/dwarf2out.c:14700
0x2ce05f loc_descriptor_from_tree
        ../../src/gcc/dwarf2out.c:15033
0x2ce0e1 tls_mem_loc_descriptor
        ../../src/gcc/dwarf2out.c:11593
0x2ce7a3 loc_descriptor
        ../../src/gcc/dwarf2out.c:13576
0x2ce821 loc_descriptor
        ../../src/gcc/dwarf2out.c:13601
0x2ceb55 dw_loc_list_1
        ../../src/gcc/dwarf2out.c:13878
0x2cbba7 dw_loc_list
        ../../src/gcc/dwarf2out.c:14148
0x2cbba7 loc_list_from_tree
        ../../src/gcc/dwarf2out.c:14584
0x2cfcaf add_location_or_const_value_attribute
        ../../src/gcc/dwarf2out.c:16092
0x2bc6ed gen_variable_die
        ../../src/gcc/dwarf2out.c:19281
0x2c298f gen_decl_die
        ../../src/gcc/dwarf2out.c:21025
0x2bdc23 process_scope_var
        ../../src/gcc/dwarf2out.c:20540
0x2bdd95 decls_for_scope
        ../../src/gcc/dwarf2out.c:20565
0x2be683 gen_subprogram_die
        ../../src/gcc/dwarf2out.c:18873
0x2c2d25 gen_decl_die
        ../../src/gcc/dwarf2out.c:20958
0x2c38bf dwarf2out_decl
        ../../src/gcc/dwarf2out.c:21391
0x2c3ef3 dwarf2out_function_decl
        ../../src/gcc/dwarf2out.c:21399
Please submit a full bug report,
with preprocessed source if appropriate.

$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/5/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
5.1~rc1-0ubuntu11' --with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-5 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=c++98 --enable-gnu-unique-object --disable-libitm
--disable-libquadmath --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-armhf/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-armhf
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-armhf
--with-arch-directory=arm --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --enable-multilib --disable-sjlj-exceptions
--with-arch=armv7-a --with-fpu=vfpv3-d16 --with-float=hard --with-mode=thumb
--disable-werror --enable-multilib --enable-checking=yes
--build=arm-linux-gnueabihf --host=arm-linux-gnueabihf
--target=arm-linux-gnueabihf
Thread model: posix
gcc version 5.0.1 20150413 (prerelease) [gcc-5-branch revision 222064] (Ubuntu
5.1~rc1-0ubuntu11)

[Bug target/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

ktkachov at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-04-15
                 CC|                            |ktkachov at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from ktkachov at gcc dot gnu.org ---
Confirmed.

[Bug target/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

--- Comment #2 from ktkachov at gcc dot gnu.org ---
The loc tree that ends up hitting the gcc_unreachable is:
 <debug_expr_decl 0x7ffff72511e0 D.4294967294
    type <integer_type 0x7ffff7035690 int sizes-gimplified asm_written public
SI
        size <integer_cst 0x7ffff7031eb8 constant 32>
        unit size <integer_cst 0x7ffff7031ed0 constant 4>
        align 32 symtab -151568224 alias set 1 canonical type 0x7ffff7035690
precision 32 min <integer_cst 0x7ffff7043108 -2147483648> max <integer_cst
0x7ffff7043120 2147483647>
        pointer_to_this <pointer_type 0x7ffff7049930>>
    visited SI file traces.i line 7 col 1
    align 1
    (debug_expr:SI D#2)>

[Bug target/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |5.0

[Bug target/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

--- Comment #3 from ktkachov at gcc dot gnu.org ---
(In reply to ktkachov from comment #2)
> The loc tree that ends up hitting the gcc_unreachable is:
>  <debug_expr_decl 0x7ffff72511e0 D.4294967294
>     type <integer_type 0x7ffff7035690 int sizes-gimplified asm_written
> public SI
>         size <integer_cst 0x7ffff7031eb8 constant 32>
>         unit size <integer_cst 0x7ffff7031ed0 constant 4>
>         align 32 symtab -151568224 alias set 1 canonical type 0x7ffff7035690
> precision 32 min <integer_cst 0x7ffff7043108 -2147483648> max <integer_cst
> 0x7ffff7043120 2147483647>
>         pointer_to_this <pointer_type 0x7ffff7049930>>
>     visited SI file traces.i line 7 col 1
>     align 1
>     (debug_expr:SI D#2)>

The switch statement in loc_list_from_tree
doesn't handle DEBUG_EXPR_DECL which is why it ICEs.
However, I'm not familiar with the code.
Should it handle DEBUG_EXPR_DECL (just return 0)?
the loc contents in the stack frame above are:
 <nop_expr 0x7ffff71d8b80
    type <integer_type 0x7ffff70350a8 sizetype public unsigned SI
        size <integer_cst 0x7ffff7031eb8 constant 32>
        unit size <integer_cst 0x7ffff7031ed0 constant 4>
        align 32 symtab 0 alias set -1 canonical type 0x7ffff70350a8 precision
32 min <integer_cst 0x7ffff7031ee8 0> max <integer_cst 0x7ffff7031000
4294967295>>

    arg 0 <debug_expr_decl 0x7ffff72511e0 D.4294967294
        type <integer_type 0x7ffff7035690 int sizes-gimplified asm_written
public SI size <integer_cst 0x7ffff7031eb8 32> unit size <integer_cst
0x7ffff7031ed0 4>
            align 32 symtab -151568224 alias set 1 canonical type
0x7ffff7035690 precision 32 min <integer_cst 0x7ffff7043108 -2147483648> max
<integer_cst 0x7ffff7043120 2147483647>
            pointer_to_this <pointer_type 0x7ffff7049930>>
        visited SI file traces.i line 7 col 1
        align 1
        (debug_expr:SI D#2)>>


is the handling of nop_expr correct here?

[Bug target/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

--- Comment #4 from ktkachov at gcc dot gnu.org ---

> The switch statement in loc_list_from_tree
> doesn't handle DEBUG_EXPR_DECL which is why it ICEs.
> However, I'm not familiar with the code.
> Should it handle DEBUG_EXPR_DECL (just return 0)?

Adding a return 0 for the DEBUG_EXPR_DECL fixes the ICE in the testcase, but I
have no idea if it's the correct thing to do.

[Bug target/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

--- Comment #5 from ktkachov at gcc dot gnu.org ---
The code around the gcc_unreachable is:
#ifdef ENABLE_CHECKING
      /* Otherwise this is a generic code; we should just lists all of
         these explicitly.  We forgot one.  */
      gcc_unreachable ();
#else
      /* In a release build, we want to degrade gracefully: better to
         generate incomplete debugging information than to crash.  */
      return NULL;
#endif


This will be hit only with checking enabled and the alternative seems to be
incomplete debugging info.

[Bug target/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Better testcase (no UB, warning free):

struct S { int s; int t; };
__thread struct S a[10];
int b;

void
foo ()
{
  int c = a[b].t;
  (void) c;
}

[Bug target/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|arm-linux-gnueabihf         |

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Happens on x86_64-linux too, started with r214899.

So, at *.optimized we have:
  # DEBUG D#2 => b
  # DEBUG D#1 => a[D#2].t
  # DEBUG c => D#1
which is expanded as:
(debug_insn 5 2 6 2 (var_location:SI D#2 (mem/c:SI (symbol_ref:SI ("b") [flags
0x82]  <var_decl 0x7f8953872990 b>) [0 b+0 S4 A32])) pr65771.c:8 -1
     (nil))
(debug_insn 6 5 7 2 (var_location:SI D#1 (mem/j:SI (plus:SI (ashift:SI
(debug_expr:SI D#2)
                (const_int 3 [0x3]))
            (const:SI (plus:SI (symbol_ref:SI ("a") [flags 0xaa]  <var_decl
0x7f8953872900 a>)
                    (const_int 4 [0x4])))) [0 a[D#2].t+0 S4 A32])) pr65771.c:8
-1
     (nil))
(debug_insn 7 6 0 2 (var_location:SI c (debug_expr:SI D#1)) pr65771.c:8 -1
     (nil))
and vartracking makes:
(note 15 2 14 2 (var_location c (mem/j:SI (plus:SI (ashift:SI (mem/c:SI
(symbol_ref:SI ("b") [flags 0x82]  <var_decl 0x7f8953872990 b>) [0 b+0 S4 A
32])
            (const_int 3 [0x3]))
        (const:SI (plus:SI (symbol_ref:SI ("a") [flags 0xaa]  <var_decl
0x7f8953872900 a>)
                (const_int 4 [0x4])))) [0 a[D#2].t+0 S4 A32]))
NOTE_INSN_VAR_LOCATION)
out of this.  Var-tracking for obvious reasons can only replace the
DEBUG_EXPR_DECLs when they appear in debug_expr RTL, because we track
DEBUG_EXPR_DECL values at RTL as RTL expressions, rather than tree.  The
problem is I believe that we try to use the MEM_EXPR as a fallback and if it
contains DEBUG_EXPR_DECL, dwarf2out.c is upset.

[Bug debug/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

ktkachov at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|target                      |debug

--- Comment #8 from ktkachov at gcc dot gnu.org ---
Changing component then

[Bug debug/65771] [5 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 35334
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35334&action=edit
gcc5-pr65771.patch

Untested fix.  Though, of course this is too risky for the 5 branch at this
point, and giving up on DEBUG_EXPR_DECL there is desirable too.  So I'll test
that first, and this patch only afterwards for the trunk only.

[Bug debug/65771] [5/6 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Fri Apr 17 07:44:30 2015
New Revision: 222166

URL: https://gcc.gnu.org/viewcvs?rev=222166&root=gcc&view=rev
Log:
    PR debug/65771
    * dwarf2out.c (loc_list_from_tree): Return NULL
    for DEBUG_EXPR_DECL.

    * gcc.dg/debug/pr65771.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/debug/pr65771.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/dwarf2out.c
    trunk/gcc/testsuite/ChangeLog

[Bug debug/65771] [5/6 Regression] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Fri Apr 17 07:45:46 2015
New Revision: 222167

URL: https://gcc.gnu.org/viewcvs?rev=222167&root=gcc&view=rev
Log:
    PR debug/65771
    * dwarf2out.c (loc_list_from_tree): Return NULL
    for DEBUG_EXPR_DECL.

    * gcc.dg/debug/pr65771.c: New test.

Added:
    branches/gcc-5-branch/gcc/testsuite/gcc.dg/debug/pr65771.c
Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/dwarf2out.c
    branches/gcc-5-branch/gcc/testsuite/ChangeLog

[Bug debug/65771] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[5/6 Regression] ICE (in    |ICE (in loc_list_from_tree,
                   |loc_list_from_tree, at      |at dwarf2out.c:14964) on
                   |dwarf2out.c:14964) on       |arm-linux-gnueabihf
                   |arm-linux-gnueabihf         |

--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
No longer a regression, keeping this open for the #c9 fix (for trunk only).

[Bug debug/65771] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Fri Apr 17 14:16:30 2015
New Revision: 222181

URL: https://gcc.gnu.org/viewcvs?rev=222181&root=gcc&view=rev
Log:
    PR debug/65771
    * dwarf2out.c (mem_loc_descriptor): For CONST, fallback to
    trying mem_loc_descriptor on XEXP (rtl, 0).

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/dwarf2out.c

[Bug debug/65771] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|5.0                         |5.2

--- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 5.1 has been released.

[Bug debug/65771] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ramana at gcc dot gnu.org

--- Comment #15 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Jakub,

Does the patch in #c9 need testing for gcc 5 and then application ?

Ramana

[Bug debug/65771] ICE (in loc_list_from_tree, at dwarf2out.c:14964) on arm-linux-gnueabihf

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65771

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|5.2                         |5.3

--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 5.2 is being released, adjusting target milestone to 5.3.