Conditional breakpoints with unmet conditions would cause next and step
to skip the line.

This breakpoint changes the Kind field of proc.Breakpoint from a single
value to a bit field, each breakpoint object can represent
simultaneously a user breakpoint and one internal breakpoint (of which
we have several different kinds).

The breakpoint condition for internal breakpoints is stored in the new
internalCond field of proc.Breakpoint so that it will not conflict with
user specified conditions.

The breakpoint setting code is changed to allow overlapping one
internal breakpoint on a user breakpoint, or a user breakpoint on an
existing internal breakpoint. All other combinations are rejected. The
breakpoint clearing code is changed to clear the UserBreakpoint bit and
only remove the phisical breakpoint if no other bits are set in the
Kind field. ClearInternalBreakpoints does the same thing but clearing
all bits that aren't the UserBreakpoint bit.

Fixes #844

gosymtab and gopclntab only contain informations about go code, linked
C code isn't there, we should use debug_line instead to also cover C.

Updates #935

Fixes #959

Splits out type parsing and go-specific Type hierarchy from
x/debug/dwarf, replace x/debug/dwarf with debug/dwarf everywhere,
remove x/debug/dwarf from vendoring.

The compiler a variable 'v' that escapes to the heap with a '&v' entry.
Auto dereference those local variables.

Fixe #871

* Fix various issues detected by megacheck

I've ran honnef.co/go/tools/cmd/megacheck and fixed a few of the
things that came up there.

* Cleanup using Gogland

Implements #727

- moved target.Interface into proc as proc.Process
- rename proc.IThread to proc.Thread
- replaced interfaces DisassembleInfo, Continuable and
  EvalScopeConvertible with Process.
- removed superfluous Gdbserver prefix from types in the gdbserial
  backend.
- removed superfluous Core prefix from types in the core backend.

- move native backend to pkg/proc/native
- move gdbserver backend to pkg/proc/gdbserial
- move core dumps backend to pkg/proc/core

Unfortunately go/constant does not support NaN and Inf float values so
we need to store this information alongside.

Fixes #705

Adds ability to load x87, SSE and AVX registers.

Fixes #666

Patch https://go-review.googlesource.com/23085 has been merged so we
can go back to using golang.org/x/debug/.

* tests: update to cope with go1.7 SSA compiler

* de-vendored golang.org/x/debug/dwarf

We need our own tweaked version

* dwarf/debug/dwarf: always use the entry's name attribute

Using the name attribute leads to better type names as well as fixes
inconsistencies between 1.5, 1.6 and 1.7.

* proc: Updated loadInterface to work with go1.7

go1.7 changed the internal representation of types, removing the string
field from runtime._type.
Updated loadInterface to use the new str field.

* service/api: Removed unused fields of service/api.Function

* proc/eval: Set return variable name to input expression

* all: fine-grained control of loadValue for better variable printing

Makes proc.(*Variable).loadValue loading parameters configurable
through one extra argument of type LoadConfig.
This interface is also exposed through the API so clients can control
how much of a variable delve should read.

Implements #109 and #120

Implements #368

Typedefs that resolve to slices are not recorded in DWARF as typedefs
but instead as structs in a way that there is no way to know they
are really slices using debug/dwarf.
Using golang.org/x/debug/dwarf instead this problem is solved and
as a bonus some types are printed with a nicer names: (struct string
→ string, struct []int → []int, etc)

 Fixes #356 and #293

Next sets its temporary breakpoints with the condition that they
must only activate on the current goroutine, and then calls Continue
When Continue encounters a temporary breakpoint it clears all
the breakpoint.

User visible changes: breakpoints that get hit while executing Next
are not ignored.

This commit does not implement full conditional breakpoints
functionality, the only condition that can be set is on the
goroutine id.

Fixes race conditions in Next affecting TestNextConcurrent.

Supported operators:

- All (binary and unary) operators between basic types except <-,
++ and -- (includes & to take the address of an expression)
- Comparison operators between supported compound types
- Typecast of integer constants into pointer types
- struct members
- indexing of arrays, slices and strings
- slicing of arrays, slices and strings
- pointer dereferencing
- true, false and nil constants

Implements #116, #117 and #251

The new contents of api.Variable are documented in
proc/variables.go.

Implements #243

Three locations are returned for goroutines: its current location,
its current location excluding unexported runtime functions and
the location of its go instruction.
The command 'goroutines' takes a new parameter to select which
location to print (defaulting to current location w/o runtime)

This adds support for breakpoints statistics

Fixes #247

The shortening of file paths is purely a terminal UI concern. Move that
code to the presentation layer, and remove from the service layer.

Allows a user to execute `dlv trace [regexp]` and Delve will execute the
program and output information on functions matching [regexp].

* Cleanup comments
* Cleanup naming in certain instances
* Modify stacktrace to return current location

Finishes #63 #64

Previously either the terminal client or the debugger service would
either lock main goroutine to a thread or provide a locked goroutine to
run _all_ DebuggedProcess functions in. This is unnecessary because only
ptrace functions need to be run from the same thread that originated the
PT_ATTACH request.

Here we use a specific thread-locked goroutine to service any ptrace
request. That goroutine is also responsible for the initial spawning /
attaching of the process, since it must be responsible for the PT_ATTACH
request.