On Fri, Nov 6, 2009 at 10:46 AM, Eric Botcazou <ebotca...@adacore.com> wrote: >> In a desparate try to get some testcases which do have BLKmode bit-fields >> I bootstrapped and regtested the below patch (as part of a larger patch, >> though) on seven architectures with all languages (on two without Ada). > > Yet it's easy in Ada on platforms with strict alignment, e.g. SPARC: > > package P is > > type Rec1 is record > I1 : Integer; > I2 : Integer; > I3 : Integer; > end record; > > type R2 is record > B : Boolean; > R : Rec1; > end record; > pragma Pack (R2); > > end P; > > (gdb) p debug_tree(0x2aaaaab2bdc0) > <field_decl 0x2aaaaab2bdc0 r > type <record_type 0x2aaaaabc64d0 p__rec1 sizes-gimplified visited BLK > size <integer_cst 0x2aaaaab27f90 constant visited 96> > unit size <integer_cst 0x2aaaaabd7d20 constant visited 12> > align 32 symtab 0 alias set -1 canonical type 0x2aaaaabc64d0 > fields <field_decl 0x2aaaaab2bb40 i1 type <integer_type 0x2aaaaabc6580 > integer> > nonaddressable SI file p.ads line 4 col 5 > size <integer_cst 0x2aaaaaaf1420 constant visited 32> > unit size <integer_cst 0x2aaaaaaf1090 constant visited 4> > align 32 offset_align 64 > offset <integer_cst 0x2aaaaaaf1b40 constant visited 0> > bit offset <integer_cst 0x2aaaaaaf1b70 constant 0> context > <record_type 0x2aaaaabc64d0 p__rec1> chain <field_decl 0x2aaaaab2bbe0 i2>> > Ada size <integer_cst 0x2aaaaab27f90 96> > reference_to_this <reference_type 0x2aaaaabc6630> chain <type_decl > 0x2aaaaab34540 p__rec1>> > external packed bit-field BLK file p.ads line 11 col 5 size <integer_cst > 0x2aaaaab27f90 96> unit size <integer_cst 0x2aaaaabd7d20 12> > align 8 offset_align 64 offset <integer_cst 0x2aaaaaaf1b40 0> > bit offset <integer_cst 0x2aaaaaaf1180 type <integer_type 0x2aaaaab010b0 > bit_size_type> constant visited 8> bit_field_type <record_type 0x2aaaaabc64d0 > p__rec1> context <record_type 0x2aaaaabc6790 p__r2>> > > We set DECL_BIT_FIELD in the front-end because the field is misaligned.
Isn't it enough to specify DECL_PACKED here? The tree.h docs about DECL_BIT_FIELD are a bit unspecific compared to DECL_PACKED. /* Nonzero in a FIELD_DECL means it is a bit field, and must be accessed specially. */ vs. /* In a FIELD_DECL, indicates this field should be bit-packed. */ where it seems, as your field isn't a bitfield, using DECL_PACKED looks more appropriate? Richard. > -- > Eric Botcazou >
