| Summary: | DW_OP_form_tls_address is unimplemented | ||
|---|---|---|---|
| Product: | gdb | Reporter: | Tom Tromey <tromey> |
| Component: | gdb | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | emaste, gbenson, gdb-prs, tromey |
| Priority: | P2 | ||
| Version: | 8.0 | ||
| Target Milestone: | 7.1 | ||
| Host: | Target: | ||
| Build: | Last reconfirmed: | 2010-07-07 15:59:41 | |
| Project(s) to access: | ssh public key: | ||
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Description
Tom Tromey
2010-05-20 19:52:44 UTC
GCC only emits it for emutls systems. In this case the value on the stack is the address of the control variable. See gcc/emutls.c for more info. Note that this means that this operator is not equivalent to DW_OP_GNU_push_tls_address. LLVM will likely start emitting this soon - see e.g. http://reviews.llvm.org/D8018 I now think it's probably fine to have gdb have to handle emultls systems differently, and just gradually move the toolchain to using the standard format. Suggested the change for gcc in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77315 The master branch has been updated by Tom Tromey <tromey@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=4aa4e28bdcf5f0d733def62b542fea11d5f219d5 commit 4aa4e28bdcf5f0d733def62b542fea11d5f219d5 Author: Tom Tromey <tom@tromey.com> Date: Mon Aug 22 16:56:52 2016 -0600 Handle DW_OP_form_tls_address Currently gdb supports DW_OP_GNU_push_tls_address, but not DW_OP_form_tls_address. I think it would be better if the toolchain as a whole moved to using the standard opcode, and the prerequisite to this is getting gdb to recognize it. GCC can sometimes emit DW_OP_form_tls_address for emultls targets. As far as I know, nobody has ever tried this with gdb (since it wouldn't work at all). I don't think there's a major drawback to using a single opcode for all targets, because computing the location of a thread-local is already target specific. This is PR gdb/11616. I don't know how to write a test case for this; though it's worth noting that there aren't explicit tests for DW_OP_GNU_push_tls_address either -- and if I change GCC, these paths will be tested to the same extent they are now. 2016-09-02 Tom Tromey <tom@tromey.com> PR gdb/11616: * dwarf2read.c (decode_locdesc): Handle DW_OP_form_tls_address. * dwarf2loc.c (dwarf2_compile_expr_to_ax): Handle DW_OP_form_tls_address. (locexpr_describe_location_piece): Likewise. * dwarf2expr.h (struct dwarf_expr_context_funcs): Update comment. * dwarf2expr.c (execute_stack_op): Handle DW_OP_form_tls_address. (ctx_no_get_tls_address): Mention DW_OP_form_tls_address. * compile/compile-loc2c.c (struct insn_info): Update comment. (compute_stack_depth_worker): Handle DW_OP_form_tls_address. Fixed. |