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Commit Graph

97 Commits

Author SHA1 Message Date
Alan Donovan
264bffc00c oracle: when 'implements' is invoked on a method, show related methods, not types.
Fixes #9972

Change-Id: I25b65a64dcc4d551be3db8566783a9d23d410a2e
Reviewed-on: https://go-review.googlesource.com/5860
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-02-25 22:38:52 +00:00
Alan Donovan
69db398fe0 go/loader: rename SourceImports flag to ImportFromBinary and invert sense
...since the zero value is more useful by far.

This is a breaking API change, obviously.  (One or two tests in this
CL have intentional been left using the zero value, i.e., they now
load source.)

Change-Id: I42287bfcdb1afef8ee84e5eac12534dd0a1fd5d2
Reviewed-on: https://go-review.googlesource.com/5653
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-02-23 23:01:10 +00:00
Alan Donovan
0dda50d42a go/loader: improve robustness in face of input errors
Before this change, many kinds of error would cause the loader to stop.
    making it brittle when analyzing large codebases, as in "godoc -analysis".

    This change moves operations that used to occur during
    configuration---(*build.Context).Import, loading, and parsing of
    initial packages---into the Load call, and ensures that all failures
    during Loading are reported at the end so that the maximum amount of
    progress is made.

    Also: redesign the tests and add many new cases.

Change-Id: Ia8cd99416af7c5d4a5fe133908adfa83676d401f
Reviewed-on: https://go-review.googlesource.com/3626
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-02-02 20:01:59 +00:00
Alan Donovan
4d45c85020 go/types: expose IsInterface predicate, eliminating 6 copies
Change-Id: I3704d7bd7a11f691c66556c1b77ef79a503d2fe9
Reviewed-on: https://go-review.googlesource.com/2173
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-01-21 18:49:27 +00:00
Peter Collingbourne
4f8578d2c0 astutil: move to go/ast/astutil
Change-Id: I9a45bfc07613eb2210081d306d71f0a4d152eda5
Reviewed-on: https://go-review.googlesource.com/2592
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-13 15:47:47 +00:00
Alan Donovan
4f13714aca astutil: add Unparen utility, eliminating 7 copies.
Change-Id: I824328c275bd6198a57edd64bf72cb2cf0490a68
Reviewed-on: https://go-review.googlesource.com/2172
Reviewed-by: Chris Manghane <cmang@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2014-12-29 22:24:57 +00:00
David Symonds
24257c8cd2 tools: add import comments.
Change-Id: Idda6e64580432cb9a731e4ebf4005ee4ceb4202d
Reviewed-on: https://go-review.googlesource.com/1244
Reviewed-by: Andrew Gerrand <adg@golang.org>
2014-12-09 22:42:16 +00:00
Daniel Morsing
25f58f97ce x/tools/oracle: add whicherrs query mode
The whicherrs query mode takes the position of an error and returns the set of constants, globals and types visible from within the scope of the error being queried.
It is meant to be used as a shortcut to find out which errors should be handled for a given functions call.

LGTM=adonovan
R=golang-codereviews, dominik.honnef, adonovan
CC=golang-codereviews
https://golang.org/cl/167420043
2014-12-05 15:51:34 +00:00
Alan Donovan
d75c6bdb8f cmd/oracle: minor fixes.
- print "oracle:" not "Error:" in error messages; remove period.
- allocate token.FileSet correctly.
- remove stale TODO (multiple test packages)
- fix typo and omission ('what') in usage message.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/178860043
2014-11-17 13:50:23 -05:00
Alan Donovan
b8d26f5b94 tools: minor comment fixes.
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/173170043
2014-11-13 12:34:25 -05:00
Andrew Gerrand
5ebbcd132f go.tools: use golang.org/x/... import paths
Rewrite performed with this command:
  sed -i '' 's_code.google.com/p/go\._golang.org/x/_g' \
    $(grep -lr 'code.google.com/p/go.' *)

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/170920043
2014-11-10 08:50:40 +11:00
Daniel Morsing
70f0e2472d go.tools/oracle: consider calls to close a peer operation.
This makes it possible to find corresponding closes to receives and sends.

LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://golang.org/cl/155260043
2014-10-12 15:08:28 +01:00
Alan Donovan
9872f0d268 go.tools/*: replace $GOROOT/src/pkg with $GOROOT/src where appropriate.
(godoc is excluded from this CL since it will continue to use
/src/pkg in its URL namespace, making the necessary cleanup
more subtle.)

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/141770043
2014-09-08 13:24:38 -04:00
Alan Donovan
95bd0c4fdf go.tools/go/types: add (*PkgName).ImportedPackage method.
It returns the value formerly returned by Pkg(), i.e. the imported package.
Pkg() now returns the package enclosing the import statement,
which is consistent with all other Objects.

Fixes golang/go#8628.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/136090043
2014-09-02 18:12:08 -04:00
Alan Donovan
4228ee8063 go.tools/go/ssa: improve printing of anonymous functions.
Examples:
- "foo$1" becomes "pkg.foo$1"
- "init$1" (meaning the first declared "init" function) becomes "init#1",
   to distinguish it from "init$1" (meaning the first anonymous function
   within the synthetic "init" function that initializes package-level vars).

It is now an invariant that all source-level (non-synthetic)
functions have distinct names, and that all names include the
enclosing package.  Added test for this.

+ updated various clients.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/122750043
2014-07-31 17:37:41 -04:00
Alan Donovan
e5d15a9781 go.tools/go/pointer: add intrinsic for time.startTimer, which is implemented in C.
Without it, no value appears to be sent on NewTicker/NewTimer channels.

+ test

Also:
- add (callgraph.Edge).{Description,Pos} convenience methods
  to simplify client code when Site==nil.

LGTM=gri
R=gri, friestein68503
CC=golang-codereviews
https://golang.org/cl/112610043
2014-07-22 18:30:06 -04:00
Alan Donovan
f9612295cb go.tools/oracle: pointsto: if the queried expression is an lvalue, use the type of its value, not its address.
(Probable regression caused by recent changes to VarValue.)

+ regression test.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/116160044
2014-07-22 18:29:56 -04:00
Alan Donovan
f2db24a319 go.tools/go/loader: use new types.TypeAndValue mode predicates.
PackageInfo:
- deleted IsType
- inlined + deleted: ValueOf, TypeCaseVar, ImportSpecPkg
- on failure, TypeOf accessor now returns nil (was: panic)

go/ssa: avoid extra map lookups by using Uses or Defs directly when safe to do so,
and keeping the TypeAndValue around in expr0().

LGTM=gri
R=gri, pcc
CC=golang-codereviews
https://golang.org/cl/107650043
2014-07-11 10:50:09 +01:00
Alan Donovan
1582053234 go.tools/oracle: remove stale item
LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/101320043
2014-06-16 15:46:56 -04:00
Alan Donovan
142566e529 go/ssa: avoid "premature optimization" of dead branch removal.
Blocks dominated by "if false" should be retained in the
initial SSA form so they remain visible to subsequent source
code analysis tools.

In any case, true compilers already need a stronger version of
this optimization so they can simplify CFGs such as this:
	const x, y = ...
        switch x {case y:...}
where a branch is constant but the comparison of constants
does not occur within an expression.

LGTM=gri
R=gri
CC=golang-codereviews, pcc
https://golang.org/cl/101250043
2014-06-12 11:31:41 -04:00
Alan Donovan
fec252214b go.tools/ssa: create thunks for method expressions T.f.
Until now, the same Function was used to represent a method
(T)func() and the "method expression" function func(T) formed
from it. So the SSA code for this:

    var buf bytes.Buffer
    f := Buffer.Bytes
    f(buf)
    buf.Bytes()

would involve an implicit cast (ChangeType) on line 2.
However, compilers based on go/ssa may want to use different
calling conventions for them, like gccgo does (see issue
7839).  This change decouples them by using an anonymous
function called a "thunk", rather like this:

    f := func(r *bytes.Buffer) []byte { return r.Bytes() }

Thunks are similar to method wrappers; both are created by
makeWrapper.

"Interface method wrappers" were a special case of thunks for
direct calls (no indirection/fields) of interface methods.
They are now subsumed by thunks and have been deleted.  Now
that only the needed thunks are built, we don't need to
populate the concrete method sets of interface types at all,
so (*Program).Method and LookupMethod return nil for them.
This results in a slight reduction in function count (>1%) and
instruction count (<<1%).

Details:

go/ssa:
- API: ChangeType no longer supports func/method conversions.
- API: (*Program).FuncValue now returns nil for abstract
  (interface) methods.
- API: (*Function).RelString simplified.
  "$bound" is now a suffix not a prefix, and the receiver
  type is rendered package-relative.
- API: Function.Object is now defined for all wrappers too.
- API: (*Program).Method and LookupMethod return nil for
  abstract methods.
- emitConv no longer permits (non-identical)
  Signature->Signature conversions.  Added assertion.
- add and use isInterface helper
- sanity: we check packages after Build, not Create, otherwise
  cross-package refs might fail.

go/pointer:
- update tests for new function strings.
- pointer_test: don't add non-pointerlike probes to analysis.
  (The error was checked, but too late, causing a panic.)
- fixed a minor bug: if a test probe print(x) was the sole
  reference to x, no nodes were generated for x.
- (reflect.Type).MethodByName: updated due to ssa API changes.
  Also, fixed incorrect testdata/funcreflect.go expectation
  for MethodByName on interfaces.

oracle:
- fix for new FuncValue semantics.
- a "pointsto" query on an I.f thunk now returns an error.

Fixes golang/go#7839

LGTM=gri
R=gri
CC=golang-codereviews, pcc
https://golang.org/cl/93780044
2014-06-11 13:10:26 -04:00
Alan Donovan
95e5e90454 go.tools/oracle: callgraph: fix crash caused by sparse node numbering.
Revision 0ea4058a1ca3 caused the node numbering to become
sparse, violating a precondition of
(*callgraphResult).toSerial.  Now we renumber the callgraph
nodes always, not just the qpos != nil case.

Fixes golang/go#8171

LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/103240044
2014-06-10 12:36:40 -04:00
Robert Griesemer
30b1abe2f7 go.tools: fix various typos
LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://golang.org/cl/97920045
2014-05-02 14:38:08 -07:00
Alan Donovan
6ec40d9aac go.tools/oracle: don't discard /usr/bin/diff's stderr
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/87980045
2014-04-15 15:39:38 -04:00
Alan Donovan
b3970ee159 go.tools/go/oracle: show import path (not just name) when describing an import.
+ test.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/88190044
2014-04-15 15:37:44 -04:00
Alan Donovan
ccb0e9ab88 go.tools/.hgignore: don't ignore test-generated files, clean them up.
(Includes rollback of CL 83680043.)

LGTM=gri
R=gri
CC=golang-codereviews, rsc
https://golang.org/cl/86430045
2014-04-10 13:17:20 -04:00
Alan Donovan
a4491f08bf go.tools/oracle: fix bug in reduceScope on ad-hoc main packages.
LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/77450048
2014-03-19 14:00:35 -04:00
Alan Donovan
ba9c801433 go.tools: various comments + doc tweaks.
No functional changes.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/74270043
2014-03-11 18:24:39 -04:00
Alan Donovan
d503a640d7 go.tools/go/ssa: name anon funcs by their enclosing func.
Before, they were named func@line:col which made them easy to find in the source if you know the file, but hard if you don't, and it made tests fragile.

Now, they are named outer$1, outer$2, etc, which makes them
more informative in a UI since "outer" has meaning.

LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/65630048
2014-02-28 10:18:55 -05:00
Alan Donovan
c509cf123c go.tools/go/pointer: recover from panic in Analyse and return an error.
This is to avoid an internal error in pointer analysis from
bringing down a long-lived application such as godoc.

LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/68930046
2014-02-27 14:13:52 -05:00
Alan Donovan
ced954c167 go.tools/go/types: split Info.Objects map into Defs and Uses.
An identifier X in anonymous struct field struct{X} is both a
definition of a field (*Var) and reference to a type
(*TypeName).  Now that we have split the map, we can capture
both of these aspects.

Interestingly, every client but one was going to extra effort
to iterate over just the uses or just the defs; this
simplifies them.

Also, fix two bug related to tagless switches:
- An entry was being recorded in the Object map for a piece of
  synthetic syntax.
- The "true" identifier was being looked up in the current scope,
  which allowed perverse users to locally redefine it.  Now
  we use the bool (not untyped boolean) constant true, per the
  consequent clarification of the spec (issue 7404).

+ tests.

Fixes golang/go#7276

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/68270044
2014-02-27 13:21:59 -05:00
David du Colombier
29d0463c1c go.tools/oracle: fix TestOracle on Plan 9
LGTM=minux.ma
R=golang-codereviews, lucio.dere, gobot, minux.ma
CC=golang-codereviews
https://golang.org/cl/64400043
2014-02-21 21:53:57 +01:00
Alan Donovan
99b2441d95 go.tools/oracle: optionally restrict 'callgraph' query to a single package.
If a -pos argument is specified, a 'callgraph' query reports only the
functions within the query package.  This produces a far more manageable
amount of information, and because we don't need to package-qualify the
names, the result is easier to read.

Added tests:
- callgraph query with/without -pos
  (The test driver was extended to allow "nopos" queries.)
- callers and callees queries don't return wrappers

Also, in go/callgraph:
- (*Node).String, (*Edge).String
- (*Graph).DeleteSyntheticNodes eliminates synthetic wrapper functions,
  preserving topology.  Used in all four oracle "call*" queries.
- (*Graph).DeleteNode

LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/66240044
2014-02-21 10:46:02 -05:00
Alan Donovan
829d52f2e8 go.tools/go/callgraph: simplifications to API.
1) We remove context sensitivity from API.  The pointer analysis is
   not sufficiently context-sensitive for the context information to
   be worth exposing.  (The actual analysis precision still benefits
   from being context-sensitive, though.)  Since all clients would
   discard the context info, we now do that for them.
2) Make the graph doubly-linked.  Edges are now shared by the Nodes
   at both ends of the edge so it's possible to navigate more easily
   (e.g. to the callers).
3) Graph and Node are now concrete, not interfaces.

Less code in every file!

LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/66460043
2014-02-20 11:57:48 -05:00
Alan Donovan
28104d2c91 go.tools/go/pointer: remove context-sensitivity from API.
Previously, each {Indirect,}Query would return a set of Pointers, one per context; now it returns (at most) one Pointer combining information from all contexts.

The old API was more faithful to the implementation concepts, but the analysis is not sufficiently context-sensitive that it makes sense: all existing clients simply throw away the context information---so now we do that for them.

(I may remove the context-sensitivity from the callgraph too, but I'll benchmark that first to see if it reduces precision.)

LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/66130044
2014-02-20 11:35:09 -05:00
Alan Donovan
03ca00ddd4 go.tools/go/types/typeutil: new package for type utilities.
Contains the members formerly known as:
- ssa.IntuitiveMethodSet
- typemap.M (now: Map)

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/65670043
2014-02-19 13:32:36 -05:00
Alan Donovan
08fadac071 go.tools/go/loader: simplify command-line syntax.
Previously, each word could be a package import path or a
comma-separated list of *.go file names.  Now, if the
first word ends with ".go", all words are assumed to be
Go source files.  This makes it impossible to specify
two ad-hoc packages from source files, but no-one needs that.

FromArgs also takes a boolean indicating whether tests
are wanted or not.

Also: ssadump: add -test flag to set that boolean.
For the oracle it's always true.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/61470047
2014-02-11 16:52:16 -05:00
Alan Donovan
1f29e74bfa go.tools/go/types: remove Type.MethodSet() method.
Method-set caching is now performed externally using a MethodSetCache (if desired), not by the Types themselves.

This a minor deoptimization due to the extra maps, but avoids a situation in which method-sets are computed and frozen prematurely. (See b/7114)

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/61430045
2014-02-11 16:49:27 -05:00
Robert Griesemer
ebfa4efbc4 go.tools/go/types: cleanup: more consistent exported predicate names
Renamed predicates:
IsIdentical -> Identical
IsAssignableTo -> AssignableTo
Signature.IsVariadic -> Signature.Variadic
Object.IsExported -> Object.Exported

LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://golang.org/cl/53370043
2014-01-28 10:57:56 -08:00
Alan Donovan
0dcaae1610 go.tools/go/loader: permit Create* methods to specify the ad-hoc package's path
CL 49530047 made the (over-)simplifying assumption that the
Path of an ad-hoc (Created) package should default to its
Name, i.e. package declaration.

With this change, the Name is still always computed from the
package declaration (by go/types) but the Path may be
specified by the loader.Config.  If "", the value of the Name
is used, which is not globally unique.

R=gri, axwalk
CC=golang-codereviews
https://golang.org/cl/55180043
2014-01-22 09:59:19 -05:00
Alan Donovan
b856247075 go.tools/call: rename package to go/callgraph
Was:		Now:
call.Graph	callgraph.Graph
call.GraphNode	callgraph.Node
call.Edge	callgraph.Edge

Though call.Graph was cute, the original naming was a mistake:
'call' is too useful a var name to waste on a package.

R=gri, crawshaw
CC=golang-codereviews
https://golang.org/cl/53190043
2014-01-16 14:04:19 -05:00
Alan Donovan
3fc0fc1310 go.tools: rename packages.
Was:		Now:
ssa		go/ssa
importer	go/loader
pointer		go/pointer

Next CL: call -> go/callgraph (requires more care)

R=gri, crawshaw
CC=golang-codereviews
https://golang.org/cl/52960043
2014-01-16 09:33:58 -05:00
Alan Donovan
d20cbc12f1 go.tools/oracle: eliminate reliance on undefined map iteration order.
(Unmasked by recent randomization of small (<8) map iteration.)

R=gri, crawshaw, bradfitz
CC=golang-codereviews
https://golang.org/cl/51170044
2014-01-15 22:55:52 -05:00
Alan Donovan
e8afbfad8c go.tools/importer: API rethink.
The Importer type has been replaced with Config and Program.

Clients populate a Config, directly or more usually via
convenience functions.  They then call its Load() method to do
all of the typechecking and transitive-closure computation.

ssa.NewProgram and ssa.CreatePackages have been fused into
ssa.Create, which now cannot fail, since (*Config).Load()
reports all type errors.

Also:
- The addition of an ssa.GlobalDebug builder mode flag
  eliminates a loop-over-packages repeated in many clients.
- PackageInfo.Err flag unexported.  Clients never see bad infos now.
- cmd/ssadump: now only looks for func "main" in package "main".
- importsOf deleted, was dead code.

STILL TODO:
- ParseFile seems like API creep (though it's convenient)
  and CreateFromFiles is dangerous (w.r.t. FileSet identity).
  Need to think more...
- the need for clients to rely on elementwise correspondence
  of Config.CreatePkgs and Program.Created is a little sad.
- The command-line interface has not changed.
  That will happen in a follow-up.
  r recommends using a repeated flag: -package p -package q ...

R=gri
CC=axwalk, frederik.zipp, golang-codereviews
https://golang.org/cl/49530047
2014-01-15 21:37:55 -05:00
Robert Griesemer
d71b7746ee go.tools/oracle: disable broken test (fix build)
R=adonovan
TBR=adonovan
CC=golang-codereviews
https://golang.org/cl/52920043
2014-01-15 16:25:40 -08:00
Robert Griesemer
29ac1365f4 go.tools/oracle: adjust golden output to new names
R=adonovan
TBR=adonovan
CC=golang-codereviews
https://golang.org/cl/49530049
2014-01-10 16:05:14 -08:00
Alan Donovan
3d82e7e94a go.tools/ssa: fix crash in SSA builder when using GCImporter to satisfy imports (ssadump -build=G).
Packages were not being created for all types.Packages,
specifically, indirectly imported packages were missing.
(*Program).CreatePackages now iterates over the type-checker's
package map too.

Also: removed all concurrency from importer.  I think it was
incorrect (and hard to fix).

Also: change LoadInitialPackages so that all named packages
are loaded from source.  This happens regardless of whether
GCImporter is used to satisfy imports.

Details:
- importer.Config.SourceImports flag determines whether to
  load all packages from *.go source.
  (Before, this was indicated by Config.Build != nil.)
- importer.Config.Build field effectively defaults to
  &go/build.Default.  A zero importer.Config is now usable.
- importer.Importer.Config field is now exported.
- LoadPackage renamed to ImportPackage since the resulting
  packages may come from GCImporter (and be incomplete).
- doImport and ImportPackage fused.

Fixes golang/go#7028

R=gri, axwalk
CC=golang-codereviews
https://golang.org/cl/48770043
2014-01-09 14:11:54 -05:00
Robert Griesemer
74d33a9c33 go.tools/go/types: use types.ChanDir instead of ast.ChanDir
Clearer code and fewer dependencies on go/ast.

R=adonovan
CC=golang-dev
https://golang.org/cl/43630043
2013-12-17 15:45:01 -08:00
Alan Donovan
8b9d1fd507 go.tools/oracle: implements: now shows whole-program implements relation for selected type.
(Previously it showed the implements relation for all types within the query package.)

R=crawshaw
CC=golang-dev
https://golang.org/cl/42000043
2013-12-13 18:00:55 -05:00
Alan Donovan
f119874203 go.tools/oracle: improvements to command set and performance.
Command set:
- what: an extremely fast query that parses a single
  file and returns the AST stack, package name and the
  set of query modes that apply to the current selection.
  Intended for GUI tools that need to grey out UI elements.
- definition: shows the definition of an identifier.
- pointsto: the PTA features of 'describe' have been split
  out into their own command.
- describe: with PTA stripped out, the cost is now bounded by
  type checking.

Performance:
- The importer.Config.TypeCheckFuncBodies predicate supports
  setting the 'IgnoreFuncBodies' typechecker flag on a
  per-package basis.  This means we can load dependencies from
  source more quickly if we only need exported types.
  (We avoid gcimport data because it may be absent or stale.)
  This also means we can run type-based queries on packages
  that aren't part of the pointer analysis scope. (Yay.)
- Modes that require only type analysis of the query package
  run a "what" query first, and restrict their analysis scope
  to just that package and its dependencies (sans func
  bodies), making them much faster.
- We call newOracle not oracle.New in Query, so that the
  'needs' bitset isn't ignored (oops!).  This makes the
  non-PTA queries faster.

Also:
- removed vestigial timers junk.
- pos.go: existing position utilties split out into own file.
  Added parsePosFlag utility.
- numerous cosmetic tweaks.

+ very basic tests.

To do in follow-ups:
- sophisticated editor integration of "what".
- better tests.
- refactoring of control flow as described in comment.
- changes to "implements", "describe" commands.
- update design doc + user manual.

R=crawshaw, dominik.honnef
CC=golang-dev, gri
https://golang.org/cl/40630043
2013-12-13 10:04:55 -05:00