https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64035
Mikhail Maltsev <miyuki at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |miyuki at gcc dot gnu.org
--- Comment #6 from Mikhail Maltsev <miyuki at gcc dot gnu.org> ---
(In reply to Jonas Platte from comment #5)
> With decent experience in C++, but no experience working on GCC (or any
> other compiler), could I help fixing this?
Certainly. Some relevant wiki pages:
https://gcc.gnu.org/wiki/GettingStarted - about contributing to GCC (in
general)
https://gcc.gnu.org/wiki/DebuggingGCC - notes on debugging
Steps which seem reasonable (for me) to start debugging this particular case:
1. build the compiler with debugging information (-ggdb3) and low optimization
level (-Og)
2. run the compiler proper from build/gcc directory under debugger (suppose
that "build" is the top-level build directory and "test.cc" is your testcase):
gdb --args ./cc1plus test.cc
(note: gdb should load .gdbinit which is created in gcc directory during build;
it contains several useful macros)
3. I hit the breakpoint in fancy_abort (it is set by .gdbinit) and go one frame
up:
#1 0x0000000000605a28 in reshape_init_r (type=<array_type 0x7ffff6800348>,
d=d@entry=0x7fffffffd870, first_initializer_p=first_initializer_p@entry=false,
complain=complain@entry=2) at /home/miyuki/gcc/src/gcc/cp/decl.c:5734
5734 gcc_assert (BRACE_ENCLOSED_INITIALIZER_P (init));
This asserion fails. I can look at the contents of "init" like this:
(gdb) p init
$1 = <constructor 0x7ffff680adf8>
(gdb) p debug_tree(init)
<constructor 0x7ffff680adf8
type <array_type 0x7ffff6800348
type <integer_type 0x7ffff669f7e0 int public SI
size <integer_cst 0x7ffff66bd0a8 constant 32>
unit size <integer_cst 0x7ffff66bd0c0 constant 4>
align 32 symtab 0 alias set -1 canonical type 0x7ffff669f7e0
precision 32 min <integer_cst 0x7ffff66bd060 -2147483648> max <integer_cst
0x7ffff66bd078 2147483647>
pointer_to_this <pointer_type 0x7ffff66c1930>>
DI
size <integer_cst 0x7ffff669be58 constant 64>
unit size <integer_cst 0x7ffff669be70 constant 8>
align 32 symtab 0 alias set -1 canonical type 0x7ffff6800348
domain <integer_type 0x7ffff68002a0 type <integer_type 0x7ffff669f1f8
sizetype>
type_6 DI size <integer_cst 0x7ffff669be58 64> unit size
<integer_cst 0x7ffff669be70 8>
align 64 symtab 0 alias set -1 canonical type 0x7ffff68002a0
precision 64 min <integer_cst 0x7ffff669be88 0> max <integer_cst 0x7ffff669bf60
1>>>
constant static lngt 0>
So, init is some AST node. If I go 4 frames up, I can see an AST for the entire
initializer:
#5 0x00000000005c0305 in implicit_conversion (to=to@entry=<record_type
0x7ffff6800150 testStruct>, from=<lang_type 0x7ffff67f6a80 init list>,
expr=expr@entry=<constructor 0x7ffff680ade0>, c_cast_p=c_cast_p@entry=false,
flags=flags@entry=5, complain=2, complain@entry=3) at
/home/miyuki/gcc/src/gcc/cp/call.c:1763
1763 expr = reshape_init (to, expr, complain);
<constructor 0x7ffff680ade0
type <lang_type 0x7ffff67f6a80 init list VOID
align 1 symtab 0 alias set -1 canonical type 0x7ffff67f6a80>
lngt 1
val <constructor 0x7ffff680adf8
type <array_type 0x7ffff6800348 type <integer_type 0x7ffff669f7e0 int>
DI
size <integer_cst 0x7ffff669be58 constant 64>
unit size <integer_cst 0x7ffff669be70 constant 8>
align 32 symtab 0 alias set -1 canonical type 0x7ffff6800348 domain
<integer_type 0x7ffff68002a0>>
constant static lngt 0>>
You need to figure out what went wrong here and why do we get unexpected AST
(perhaps by comparing it with AST that is built in "func({{}});" case).
