On Windows we can sometimes encounter threads stopped in locations for
which we do not have entries in debug_frame.
These cases seem to be due to calls to Windows API in the go runtime,
we can still produce a (partial) stack trace in this circumstance by
following frame pointers (starting with BP).
We still prefer debug_frame entries when available since go functions
do not have frame pointers before go1.8.

Sometimes windows will send us events about breakpoints we have
already removed from the code despite the fact that we go to great
lengths to avoid this already.

Change waitForDebugEvent to check that when we receive a breakpoint
event the corresponding memory actually contains an INT 3
instruction, if it doesn't ignore the event and restart the thread.

Changes to the GC in 1.8 make this test fail because the GC isn't
inserting stack barriers into our test program anymore. This isn't the
same thing as being unable to print stacktraces in presence of stack
barriers so the test shouldn't fail.

The PC we have is relative to the first instruction after the CALL
instruction currently being executed.

Anyone watching a disassembly will understand what's happening if we
report the return PC, but reporting the first PC of the current line is
useless and confusing.

Fixes #732

loadValue didn't react correctly to pointer loops going through
slice -> interface{} -> slice or pointer -> interface{} -> pointer.

Fixes #729

Signed-off-by: NKoichi Shiraishi <zchee.io@gmail.com>

Under currently undetermined circumstances we encounter a map type that
has a malformed buckets, oldbuckets or overflow field.
Check the type of buckets, oldbuckets and overflow before using them.

Fixes #685

* service/rpccommon: fixed typo

* proc: test parseG while target is in runtime.deferreturn

runtime.deferreturn will change the value of curg._defer.fn in such a
way that if the target is stopped at just the right instruction it
may crash an incorrect implementation of parseG

* proc/stack: handle stack barriers correctly

Correctly handle stack barriers insterted during garbage collection.

We are already doing this in GoroutinesInfo we should be doing it for
GetG. The main consequence of not doing this is that the CurrentLoc of
DebuggerState.SelectedGoroutine is out of date compared to the location
of the thread running it.

* proc: Added trace benchmark

Results:

BenchmarkTrace-4   	    5000	  36195899 ns/op

* proc/linux: faster single step implementation.

BenchmarkTrace-4   	    5000	   2093271 ns/op

* proc: Cache function debug_info entries to speed up variable lookup.

BenchmarkTrace-4   	    5000	   1864846 ns/op

* proc/variables: Optimize FunctionArguments by prefetching frame

BenchmarkTrace-4   	    5000	   1815795 ns/op

* proc/variables: optimized parseG

BenchmarkTrace-4   	   10000	    712767 ns/op

* dwarf/line: bugfix: not all values of the state machine can be used

According to DWARF Version 3 Section 6.2 "Line Number Information" not
all the values transversed by the line numbers state machine are valid
instructions, only the ones after a "special opcode", after the
standard opcode DW_LNS_copy and the extended opcode
DW_LINE_end_sequence.

DWARF3 describes this by specifying that only the opcodes listed above
"append a row to the matrix".

Additionally the implementation of DW_LNS_const_add_pc was wrong.

Fixes #664

* dwarf/line: fixed test failing with go1.8

* service/test: fix prologue detection tests

The conditions about which function prologue is emitted by the compiler
changed in go1.8, changed the test program so that callme2 will still
have a prologue under go1.8.

* service/test: fix step test

compilation units are linked in a different order under go1.8 so the
code of 'fmt' is no longer located after 'main' in the executable,
changed the tests so that they don't rely on this assumption anymore.

* proc: change runtime.Breakpoint support for go1.8

Before 1.8 it was sufficient to step twice to exit a
runtime.Breakpoint(), but go 1.8 added frame pointer tracking to small
functions making runtime.Breakpoint longer.
This changes runtime.Breakpoint handling in Continue to single step as
many times as are needed to exit runtime.Breakpoint.

* proc/test: fix TestIssue561 for go1.8

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

Fixes #705

* service: Prevent panics from crashing delve and killing the target

Catch all unrecovered proc and debugger panics in the service layer and
report them as errors, allow users to cleanly detach from the target
and quit.

Fixes #614

* proc: Next/Step should not panic if line info can not be found.

Fixes #683

Improved prologue detection for big stackframes and added references to
the function of the compiler that inserts the prologue.

* terminal: fixed typo.

* debugger: bugfix: when restaring use new process to FindFileLocation

* service/debugger: Restore breakpoints using file:line on restart

Restoring by address can cause the breakpoint to be inserted in the
middle of an instruction if the executable file has changed.

* terminal: Warn of stale executable when printing source

Adds ability to load x87, SSE and AVX registers.

Fixes #666

Fixes #645

Since we store all signed integers as int64 the sign bit should be
extended, otherwise we read negative integers as their 2-complement
value.

* proc: Add `wd` to Launch

This change adds the `wd` arg which specify working directory of the
program.

Fixes #295

* service/debugger: Add `Wd` field to debugger.Config

This change adds the `Wd` field which specify working directory of the
program launched by debugger.

Fixes #295

* service: Add `Wd` to service.Config

This change adds the `Wd` field which specify working directory of the
program debugger will launch.

Fixes #295

* cmd/dlv: Add `Wd` flag

This change adds `Wd` flag which specify working directory of the
program which launched by debugger.

Fixes #295

* only set the Linux working directory if it is set,
stub out param in darwin and windows

* set working directory for Windows
https://godoc.org/golang.org/x/sys/windows#CreateProcess
https://msdn.microsoft.com/en-us/library/windows/desktop/ms682425(v=vs.85).aspx

* Windows workingDir must be an *uint16

* attempt to chdir on darwin via @yuntan

* proc/exec_darwin.c: fix working directory for darwin

* Add tests to check if working directory works.
* Fix darwin implementation of fork/exec, which paniced if
  child fork returned.

* cmd, service: rename Wd to WorkingDir

Generate names of the concrete types stored inside interface variables
by fully parsing their runtime._type instead of simply using the str
field.

This allows delve to read the contents of an interface variable when
the program imports multiple packages that have the same name. It also
allows delve to correctly interpret some complex anonymous types.

Fixes #455

Allows to rewrite a source path stored in program's debug information,
if the sources were moved to a different place between compilation and
debugging.

Command to step out of the currently executing function.

Implements #358

If the location specification matches the name of a function exactly
return that function as a match event if the expression matches other
functions as well.

Without this some functions, like math/rand.Intn are unmatchable.

* proc: changed windows backend to deal with simultaneous breakpoints

* bugfix: forgot to add windowsPrologue3 to the prologues list in e4c7df14

* Tolerate errors returned by Stacktrace in TestStacktraceGoroutine.

* bugfix: proc: propagate debug events we don't cause back to the target process

Fixes: #594

* proc: fixed TestStepConcurrentPtr

Implementation of nextInProgress was wrong.