On 14/07/2021 19:40, Mark Wielaard wrote:
AC_CACHE_CHECK([whether gcc supports __attribute__((visibility()))], ac_cv_visibility, [dnl diff --git a/src/readelf.c b/src/readelf.c index 161d7e65..3d6f263e 100644 --- a/src/readelf.c +++ b/src/readelf.c @@ -8763,13 +8763,17 @@ print_debug_line_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr, /* Apply the "operation advance" from a special opcode or DW_LNS_advance_pc (as per DWARF4 6.2.5.1). */ unsigned int op_addr_advance; - inline void advance_pc (unsigned int op_advance) - { - op_addr_advance = minimum_instr_len * ((op_index + op_advance) - / max_ops_per_instr); - address += op_addr_advance; - op_index = (op_index + op_advance) % max_ops_per_instr; - } + bool show_op_index; + #define advance_pc(op_advance_arg) \ + ( { \ + unsigned int op_advance = op_advance_arg; \ + op_addr_advance = minimum_instr_len * ((op_index + (op_advance)) \ + / max_ops_per_instr); \ + address += (op_advance); \ + show_op_index = (op_index > 0 || \ + (op_index + (op_advance)) % max_ops_per_instr > 0); \ + op_index = (op_index + (op_advance)) % max_ops_per_instr; \ + } )This doesn't compile with gcc: readelf.c: In function ‘print_debug_line_section’: readelf.c:8766:12: error: variable ‘show_op_index’ set but not used [-Werror=unused-but-set-variable] 8766 | bool show_op_index; | ^~~~~~~~~~~~~ cc1: all warnings being treated as errors Removing the unused show_op_index makes two testcases fail: FAIL: run-readelf-line.sh ========================= --- readelf.out 2021-07-14 19:37:00.962372827 +0200 +++ - 2021-07-14 19:37:00.971161054 +0200 @@ -42,13 +42,13 @@ [ 36] set prologue end flag [ 37] special opcode 19: address+0 = 0x100005a4 <main>, line+1 = 6 [ 38] set column to 8 - [ 3a] special opcode 47: address+8 = 0x100005a6 <main+0x2>, line+1 = 7 + [ 3a] special opcode 47: address+8 = 0x100005ac <main+0x8>, line+1 = 7 [ 3b] set 'is_stmt' to 0 [ 3c] advance line by constant -7 to 0 - [ 3e] special opcode 32: address+4 = 0x100005a7 <main+0x3>, line+0 = 0 + [ 3e] special opcode 32: address+4 = 0x100005b0 <main+0xc>, line+0 = 0 [ 3f] set column to 3 [ 41] set 'is_stmt' to 1 - [ 42] special opcode 108: address+24 = 0x100005ad <main+0x9>, line+6 = 6 - [ 43] special opcode 76: address+16 = 0x100005b1 <main+0xd>, line+2 = 8 - [ 44] advance address by 32 to 0x100005b9 <main+0x15> + [ 42] special opcode 108: address+24 = 0x100005c8 <main+0x24>, line+6 = 6 + [ 43] special opcode 76: address+16 = 0x100005d8 <main+0x34>, line+2 = 8 + [ 44] advance address by 32 to 0x100005f8 [ 46] extended opcode 1: end of sequence FAIL run-readelf-line.sh (exit status: 1) FAIL: run-readelf-multi-noline.sh ================================= --- readelf.out 2021-07-14 19:37:10.054186557 +0200 +++ - 2021-07-14 19:37:10.062074795 +0200 @@ -112,6 +112,6 @@ [ 6e] extended opcode 2: set address to +0x724 <main> [ 79] copy [ 7a] set column to 15 - [ 7c] special opcode 32: address+4 = +0x725 <main+0x1>, line+0 = 1 - [ 7d] advance address by 4 to +0x726 <main+0x2> + [ 7c] special opcode 32: address+4 = +0x728 <main+0x4>, line+0 = 1 + [ 7d] advance address by 4 to +0x72c [ 7f] extended opcode 1: end of sequence FAIL run-readelf-multi-noline.sh (exit status: 1)
FWIW, there is a different version of this patch at https://sourceware.org/pipermail/elfutils-devel/2021q1/003674.html that doesn't have those problems as far as I remember.
