public inbox for gcc-prs@sourceware.org help / color / mirror / Atom feed
From: johnb@stl.sarov.ru To: gcc-gnats@gcc.gnu.org Subject: other/8540: libgcc: execute_cfa_program() doesn`t handle 2 DWARF instructions properly Date: Tue, 19 Nov 2002 13:26:00 -0000 [thread overview] Message-ID: <20021112091358.8538.qmail@sources.redhat.com> (raw) >Number: 8540 >Category: other >Synopsis: libgcc: execute_cfa_program() doesn`t handle 2 DWARF instructions properly >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: wrong-code >Submitter-Id: net >Arrival-Date: Tue Nov 12 01:16:04 PST 2002 >Closed-Date: >Last-Modified: >Originator: Eugeny Belov >Release: gcc 3.2 >Organization: >Environment: Red Hat Linux 8.0, default gcc 3.2 and its sources. >Description: Source file gcc/unwind-dw2.c have the function execute_cfa_program(), part of its code is below: ... case DW_CFA_restore_extended: insn_ptr = read_uleb128 (insn_ptr, ®); fs->regs.reg[reg].how = REG_UNSAVED; break; case DW_CFA_undefined: case DW_CFA_same_value: case DW_CFA_nop: break; ... In case of DW_CFA_undefined and DW_CFA_same_value this function does nothing, but according to DWARF Debugging Information Format document (I have rev.2.1 Draft 5DW (Nov 30,2000)) section 6.4.2 (Call Frame Instructions).10,11 "the DW_CFA_undefined and DW_CFA_same_value instructions take a single unsigned LEB128 argument that represents a register number. The required action is to set the rule for the specified register to "undefined" or "same_value" in corresponding cases". Also I noted that emitting of these instructions is correct (source file gcc/dwarf2out.c:output_cfi()) but these instructions never go to the output CFI, so this is not a problem for gcc compiled programs, but may cause problems with modules built by other compilers. >How-To-Repeat: >Fix: Small changes to the gcc/unwind-dw2.c (execute_cfa_program()): ... case DW_CFA_undefined: insn_ptr = read_uleb128 (insn_ptr, ®); // if it will be used also something like this // fs->regs.reg[reg].how = REG_UNDEFINED; break; case DW_CFA_same_value: insn_ptr = read_uleb128 (insn_ptr, ®); // if it will be used also something like this // fs->regs.reg[reg].how = REG_SAMEVALUE; break; case DW_CFA_nop: break; ... >Release-Note: >Audit-Trail: >Unformatted:
reply other threads:[~2002-11-12 9:16 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20021112091358.8538.qmail@sources.redhat.com \ --to=johnb@stl.sarov.ru \ --cc=gcc-gnats@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).