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[PATCH v2 00/13] No-debug-info debugging improvements


New in v2:
  - The new simpler cast-return-type syntax now assumes the called
    function is prototyped instead of unprototyped:
     https://sourceware.org/ml/gdb-patches/2017-07/msg00128.html
  - Documentation patch adjusted accordingly.
  - The fix for calling prototyped functions via function pointers is
    now patch #1, because the v2 of patch #2 includes new tests that
    depend on the fix.


This series stops GDB from assuming that no-debug-info functions
return int, and that no-debug-info variables have type int.

E.g. instead of this, if you have no debug info for glibc:

  (gdb) p getenv("PATH")
  $1 = -6185

You'll get:

  (gdb) p getenv ("PATH")
  'getenv' has unknown return type; cast the call to its declared return type
  (gdb) p (char *) getenv ("PATH")                      # now Just Works
  $1 = 0x7fffffffe7d7 "/usr/local/bin:/"...
  (gdb) p ((char *(*) (const char *)) getenv) ("PATH")  # continues working
  $1 = 0x7fffffffe7d7 "/usr/local/bin:/"...

And similarly for variables.

While implementing and writing tests for the above, I ran into a few
other problems (as usual...), and fixed them too.  Most of the
problems were related to printing static local variables, with the
documented "p klass::method()::static_var" syntax.

One other problem I ran into today while writing the documentation
patch...  I wanted to document when to call a no-debug-info function
by casting it to the right function pointer type, and calling that
pointer, and noticed that that doesn't actually work correctly...  GDB
always leaves the target function type of the function pointer type as
an unprototyped function, meaning that it applies argument coercion
incorrectly.  W00t!

See many more details and rationale on the description of each patch.
Documentation is in the last patch.

Tested on x86-64 GNU/Linux, native and gdbserver, both with and
without glibc debug info.  Adds over 3700 new passes:

  -# of expected passes           39661
  +# of expected passes           43405

I see this series as follow up to the recent "whatis" fixes for Zack's
errno pretty printer:

  https://sourceware.org/ml/gdb-patches/2017-06/msg00827.html
  https://sourceware.org/ml/gdb-patches/2017-07/msg00018.html

so I put this series on top of those patches in the same branch:

  users/palves/whatis

Pedro Alves (13):
  Fix calling prototyped functions via function pointers
  Stop assuming no-debug-info functions return int
  Introduce OP_VAR_MSYM_VALUE
  Make ptype/whatis print function name of functions with no debug info
    too
  evaluate_subexp_standard: Eliminate one goto
  evaluate_subexp_standard: Remove useless assignments
  evaluate_subexp_standard: Factor out OP_VAR_VALUE handling.
  Stop assuming no-debug-info variables have type int
  Eliminate UNOP_MEMVAL_TLS
  Handle "p S::method()::static_var" in the C++ parser
  Handle "p 'S::method()::static_var'" (quoted) in symbol lookup
  Make "p S::method() const::static_var" work too
  Document "no debug info debugging" improvements

 gdb/doc/gdb.texinfo                                | 114 +++++-
 gdb/NEWS                                           |  26 ++
 gdb/ada-lang.c                                     |  11 +-
 gdb/ada-typeprint.c                                |   7 +-
 gdb/ax-gdb.c                                       |  72 +++-
 gdb/c-exp.y                                        |  51 ++-
 gdb/c-typeprint.c                                  |  10 +-
 gdb/compile/compile-c-symbols.c                    |   4 +-
 gdb/compile/compile-c-types.c                      |  35 +-
 gdb/compile/compile-object-run.c                   |   3 +-
 gdb/cp-namespace.c                                 |  50 +--
 gdb/dwarf2read.c                                   |  46 ++-
 gdb/elfread.c                                      |   2 +-
 gdb/eval.c                                         | 439 ++++++++++++++-------
 gdb/expprint.c                                     |  92 +++--
 gdb/expression.h                                   |   1 +
 gdb/f-typeprint.c                                  |   7 +-
 gdb/gcore.c                                        |   2 +-
 gdb/gdbtypes.c                                     |  27 +-
 gdb/gdbtypes.h                                     |  15 +-
 gdb/guile/scm-value.c                              |   2 +-
 gdb/infcall.c                                      |  49 ++-
 gdb/infcall.h                                      |  19 +-
 gdb/linux-fork.c                                   |   6 +-
 gdb/linux-tdep.c                                   |   4 +-
 gdb/m2-typeprint.c                                 |  11 +-
 gdb/minsyms.h                                      |   9 +
 gdb/objc-lang.c                                    |  14 +-
 gdb/p-typeprint.c                                  |  57 +--
 gdb/parse.c                                        | 130 +++---
 gdb/parser-defs.h                                  |   2 +
 gdb/python/py-value.c                              |   3 +-
 gdb/rust-lang.c                                    |   2 +-
 gdb/std-operator.def                               |  43 +-
 gdb/testsuite/gdb.asm/asm-source.exp               |   8 +-
 .../gdb.base/break-main-file-remove-fail.exp       |   2 +-
 gdb/testsuite/gdb.base/break-probes.exp            |   2 +-
 gdb/testsuite/gdb.base/callfuncs.exp               |  26 +-
 gdb/testsuite/gdb.base/checkpoint.exp              |  44 +--
 gdb/testsuite/gdb.base/dprintf-detach.exp          |   2 +-
 gdb/testsuite/gdb.base/infcall-exec.exp            |   2 +-
 gdb/testsuite/gdb.base/info-os.exp                 |   8 +-
 gdb/testsuite/gdb.base/nodebug.c                   |  48 +++
 gdb/testsuite/gdb.base/nodebug.exp                 | 194 +++++++--
 gdb/testsuite/gdb.base/solib-display.exp           |  16 +-
 gdb/testsuite/gdb.compile/compile-ifunc.exp        |   5 +-
 gdb/testsuite/gdb.compile/compile.exp              |  10 +-
 gdb/testsuite/gdb.cp/local-static.c                | 170 ++++++++
 gdb/testsuite/gdb.cp/local-static.cc               |   1 +
 gdb/testsuite/gdb.cp/local-static.exp              | 241 +++++++++++
 gdb/testsuite/gdb.cp/m-static.exp                  |   5 -
 gdb/testsuite/gdb.dwarf2/dw2-skip-prologue.exp     |   2 +-
 gdb/testsuite/gdb.threads/siginfo-threads.exp      |   7 +-
 gdb/testsuite/gdb.threads/tls-nodebug.exp          |   5 +-
 gdb/testsuite/gdb.trace/entry-values.exp           |   6 +-
 gdb/typeprint.c                                    |  18 +-
 gdb/typeprint.h                                    |   9 +
 gdb/valarith.c                                     |   4 +-
 gdb/valops.c                                       |   7 +-
 59 files changed, 1753 insertions(+), 454 deletions(-)
 create mode 100644 gdb/testsuite/gdb.cp/local-static.c
 create mode 100644 gdb/testsuite/gdb.cp/local-static.cc
 create mode 100644 gdb/testsuite/gdb.cp/local-static.exp

-- 
2.5.5


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