From 649ce3f25afb756432e9e3c8558bf09f3daef4e5 Mon Sep 17 00:00:00 2001 From: Jason Merrill Date: Thu, 29 Nov 2001 21:38:43 -0500 Subject: [PATCH] dwarf2out.c (add_data_member_location_attribute): Do the right thing for virtual bases. * dwarf2out.c (add_data_member_location_attribute): Do the right thing for virtual bases. * dbxout.c (dbxout_type): For a virtual base, print the offset within the vtable. From-SVN: r47469 --- gcc/ChangeLog | 7 ++++++ gcc/dbxout.c | 11 +++++++-- gcc/dwarf2out.c | 66 ++++++++++++++++++++++++++++++++++++++++--------- 3 files changed, 70 insertions(+), 14 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 00f7de42a1f..013d1f7a010 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2001-11-30 Jason Merrill + + * dwarf2out.c (add_data_member_location_attribute): Do the + right thing for virtual bases. + * dbxout.c (dbxout_type): For a virtual base, print the offset + within the vtable. + 2001-11-29 Zoltan Hidvegi * doloop.c (doloop_valid_p): Check for LTU and GTU as well. diff --git a/gcc/dbxout.c b/gcc/dbxout.c index 344ebbefeae..8b14f5d2efe 100644 --- a/gcc/dbxout.c +++ b/gcc/dbxout.c @@ -1492,8 +1492,15 @@ dbxout_type (type, full) putc (TREE_VIA_VIRTUAL (child) ? '1' : '0', asmfile); putc (TREE_VIA_PUBLIC (child) ? '2' : '0', asmfile); CHARS (2); - print_wide_int (tree_low_cst (BINFO_OFFSET (child), 0) - * BITS_PER_UNIT); + if (TREE_VIA_VIRTUAL (child)) + /* For a virtual base, print the (negative) offset within + the vtable where we must look to find the necessary + adjustment. */ + print_wide_int (tree_low_cst (BINFO_VPTR_FIELD (child), 0) + * BITS_PER_UNIT); + else + print_wide_int (tree_low_cst (BINFO_OFFSET (child), 0) + * BITS_PER_UNIT); putc (',', asmfile); CHARS (1); dbxout_type (BINFO_TYPE (child), 0); diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c index e5573bbd638..55bb26420bd 100644 --- a/gcc/dwarf2out.c +++ b/gcc/dwarf2out.c @@ -8407,28 +8407,70 @@ add_data_member_location_attribute (die, decl) dw_die_ref die; tree decl; { - unsigned long offset; - dw_loc_descr_ref loc_descr; - enum dwarf_location_atom op; + long offset; + dw_loc_descr_ref loc_descr = 0; if (TREE_CODE (decl) == TREE_VEC) - offset = tree_low_cst (BINFO_OFFSET (decl), 0); + { + /* We're working on the TAG_inheritance for a base class. */ + + if (TREE_VIA_VIRTUAL (decl)) + { + /* For C++ virtual bases we can't just use BINFO_OFFSET, as they + aren't at a fixed offset from all (sub)objects of the same + type. We need to extract the appropriate offset from our + vtable. The following dwarf expression means + + BaseAddr = ObAddr + *((*ObAddr) - Offset) + + This is specific to the V3 ABI, of course. */ + + dw_loc_descr_ref tmp; + /* Make a copy of the object address. */ + tmp = new_loc_descr (DW_OP_dup, 0, 0); + add_loc_descr (&loc_descr, tmp); + /* Extract the vtable address. */ + tmp = new_loc_descr (DW_OP_deref, 0, 0); + add_loc_descr (&loc_descr, tmp); + /* Calculate the address of the offset. */ + offset = tree_low_cst (BINFO_VPTR_FIELD (decl), 0); + if (offset >= 0) + abort (); + tmp = int_loc_descriptor (-offset); + add_loc_descr (&loc_descr, tmp); + tmp = new_loc_descr (DW_OP_minus, 0, 0); + add_loc_descr (&loc_descr, tmp); + /* Extract the offset. */ + tmp = new_loc_descr (DW_OP_deref, 0, 0); + add_loc_descr (&loc_descr, tmp); + /* Add it to the object address. */ + tmp = new_loc_descr (DW_OP_plus, 0, 0); + add_loc_descr (&loc_descr, tmp); + } + else + offset = tree_low_cst (BINFO_OFFSET (decl), 0); + } else offset = field_byte_offset (decl); - /* The DWARF2 standard says that we should assume that the structure address - is already on the stack, so we can specify a structure field address - by using DW_OP_plus_uconst. */ + if (! loc_descr) + { + enum dwarf_location_atom op; + + /* The DWARF2 standard says that we should assume that the structure address + is already on the stack, so we can specify a structure field address + by using DW_OP_plus_uconst. */ #ifdef MIPS_DEBUGGING_INFO - /* ??? The SGI dwarf reader does not handle the DW_OP_plus_uconst operator - correctly. It works only if we leave the offset on the stack. */ - op = DW_OP_constu; + /* ??? The SGI dwarf reader does not handle the DW_OP_plus_uconst operator + correctly. It works only if we leave the offset on the stack. */ + op = DW_OP_constu; #else - op = DW_OP_plus_uconst; + op = DW_OP_plus_uconst; #endif - loc_descr = new_loc_descr (op, offset, 0); + loc_descr = new_loc_descr (op, offset, 0); + } add_AT_loc (die, DW_AT_data_member_location, loc_descr); }