From 32ef30002cee3661eb645cd14bcc4ff77ea10f45 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Fri, 27 Oct 2017 09:01:36 -0400 Subject: [PATCH] dwarf: Read register number as unsigned in DW_CFA_def_cfa* MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When displaying the .debug_frame section, the register numbers in the DW_CFA_def_cfa* statements are read as signed numbers. I have come across a target that has register 121, encoded as 0x79 in unsigned LEB128. Interpreting this as signed results in -7, which makes readelf display "r-7". The DWARF5 standard (6.4.2.2) states that the register numbers should be treated as unsigned LEB128. Simply replacing READ_SLEB with READ_ULEB resulted in warnings like these: /home/emaisin/src/binutils-gdb/binutils/dwarf.c: In function ‘display_debug_frames’: /home/emaisin/src/binutils-gdb/binutils/dwarf.c:355:17: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if ((var) != _val) \ ^ /home/emaisin/src/binutils-gdb/binutils/dwarf.c:7866:8: note: in expansion of macro ‘READ_ULEB’ READ_ULEB (fc->cfa_reg); ^ ... so I also changed Frame_Chunk::cfa_reg to an unsigned int. binutils/ChangeLog: * dwarf.c (struct Frame_Chunk) : Change type to unsigned int. (display_debug_frames): Read CFA reg as an unsigned number. --- binutils/ChangeLog | 6 ++++++ binutils/dwarf.c | 8 ++++---- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/binutils/ChangeLog b/binutils/ChangeLog index ad9d33bb992..8d77c68b912 100644 --- a/binutils/ChangeLog +++ b/binutils/ChangeLog @@ -1,3 +1,9 @@ +2017-10-27 Simon Marchi + + * dwarf.c (struct Frame_Chunk) : Change type to + unsigned int. + (display_debug_frames): Read CFA reg as an unsigned number. + 2017-10-25 Alan Modra * nm.c (filter_symbols): Match "__gnu_lto_slim" optionally prefixed diff --git a/binutils/dwarf.c b/binutils/dwarf.c index 06702ef42dd..873f104174d 100644 --- a/binutils/dwarf.c +++ b/binutils/dwarf.c @@ -6646,7 +6646,7 @@ typedef struct Frame_Chunk int data_factor; dwarf_vma pc_begin; dwarf_vma pc_range; - int cfa_reg; + unsigned int cfa_reg; dwarf_vma cfa_offset; unsigned int ra; unsigned char fde_encoding; @@ -7863,7 +7863,7 @@ display_debug_frames (struct dwarf_section *section, break; case DW_CFA_def_cfa: - READ_SLEB (fc->cfa_reg); + READ_ULEB (fc->cfa_reg); READ_ULEB (fc->cfa_offset); fc->cfa_exp = 0; if (! do_debug_frames_interp) @@ -7872,7 +7872,7 @@ display_debug_frames (struct dwarf_section *section, break; case DW_CFA_def_cfa_register: - READ_SLEB (fc->cfa_reg); + READ_ULEB (fc->cfa_reg); fc->cfa_exp = 0; if (! do_debug_frames_interp) printf (" DW_CFA_def_cfa_register: %s\n", @@ -7991,7 +7991,7 @@ display_debug_frames (struct dwarf_section *section, break; case DW_CFA_def_cfa_sf: - READ_SLEB (fc->cfa_reg); + READ_ULEB (fc->cfa_reg); READ_ULEB (fc->cfa_offset); fc->cfa_offset = fc->cfa_offset * fc->data_factor; fc->cfa_exp = 0; -- 2.30.2