From 048fde1ef43843aa67e9ac30829e0d30f019a7dd Mon Sep 17 00:00:00 2001 From: nitachra Date: Sun, 20 Sep 2020 23:22:59 +0530 Subject: DWARFv5: Handle DW_MACRO_define_strx and DW_MACRO_undef_strx macro entries. GDB complaints "During symbol reading: unrecognized DW_MACFINO opcode 0xb" with the testcase given below. Clang is emitting DW_MACRO_define_strx and DW_MACRO_undef_strx entries in .debug_macro section which are not supported in GDB. This patch handles them. DW_MACRO_define_strx and DW_MACRO_undef_strx are added in DWARFv5. They have two operands. The first operand encodes the line number of the #define or #undef macro directive. The second operand identifies a string; it is represented using an unsigned LEB128 encoded value, which is interpreted as a zero-based index into an array of offsets in the .debug_str_offsets section. This is as per the section 6.3.2.1 of Dwarf Debugging Information Format Version 5. Test case used: #define MAX_SIZE 10 int main(void) { int size = 0; size = size + MAX_SIZE; printf("\n The value of size is [%d]\n",size); return 0; } clang -gdwarf-5 -fdebug-macro macro.c -o macro.out Before the patch: gdb/new_gdb/binutils-gdb/build/bin/gdb -q macro.out -ex "set complaints 1" -ex "start" Reading symbols from macro.out... During symbol reading: unrecognized DW_MACFINO opcode 0xb Temporary breakpoint 1 at 0x4004df: file macro.c, line 7. Starting program: /home/nitika/workspace/macro.out Temporary breakpoint 1, main () at macro.c:7 7 int size = 0; (gdb) Tested by running the testsuite before and after the patch with -gdwarf-5 and there is no increase in the number of test cases that fails. Used clang 11.0.0. gdb/ChangeLog: * dwarf2/macro.c (dwarf_decode_macro_bytes): Handle DW_MACRO_define_strx and DW_MACRO_undef_strx. (dwarf_decode_macros): Likewise * dwarf2/read.c (dwarf_decode_macros): Pass str_offsets_base in the parameters which is the value of DW_AT_str_offsets_base. * dwarf2/macro.h (dwarf_decode_macros): Modify the definition to include str_offsets_base. --- gdb/dwarf2/read.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) (limited to 'gdb/dwarf2/read.c') diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index 973a375..eedfea1 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -23900,8 +23900,27 @@ dwarf_decode_macros (struct dwarf2_cu *cu, unsigned int offset, buildsym_compunit *builder = cu->get_builder (); + struct dwarf2_section_info *str_offsets_section; + struct dwarf2_section_info *str_section; + ULONGEST str_offsets_base; + + if (cu->dwo_unit != nullptr) + { + str_offsets_section = &cu->dwo_unit->dwo_file + ->sections.str_offsets; + str_section = &cu->dwo_unit->dwo_file->sections.str; + str_offsets_base = cu->header.addr_size; + } + else + { + str_offsets_section = &per_objfile->per_bfd->str_offsets; + str_section = &per_objfile->per_bfd->str; + str_offsets_base = *cu->str_offsets_base; + } + dwarf_decode_macros (per_objfile, builder, section, lh, - offset_size, offset, section_is_gnu); + offset_size, offset, str_section, str_offsets_section, + str_offsets_base, section_is_gnu); } /* Return the .debug_loc section to use for CU. -- cgit v1.1