Features:
More robust: silently ignore type errors in modes that don't need
SSA form: describe, referrers, implements, freevars, description.
This makes the tool much more robust for everyday queries.
Less configuration: don't require a scope argument for all queries.
Only queries that do pointer analysis need it.
For the rest, the initial position is enough for
importQueryPackage to deduce the scope.
It now works for queries in GoFiles, TestGoFiles, or XTestGoFiles.
(It no longer works for ad-hoc main packages like
$GOROOT/src/net/http/triv.go)
More complete: "referrers" computes the scope automatically by
scanning the import graph of the entire workspace, using gorename's
refactor/importgraph package. This requires two passes at loading.
Faster: simplified start-up logic avoids unnecessary package loading
and SSA construction (a consequence of bad abstraction) in many
cases.
"callgraph": remove it. Unlike all the other commands it isn't
related to the current selection, and we have
golang.org/x/tools/cmdcallgraph now.
Internals:
Drop support for long-running clients (i.e., Pythia), since
godoc -analysis supports all the same features except "pointsto",
and precomputes all the results so latency is much lower.
Get rid of various unhelpful abstractions introduced to support
long-running clients. Expand out the set-up logic for each
subcommand. This is simpler, easier to read, and gives us more
control, at a small cost in duplication---the familiar story of
abstractions.
Discard PTA warnings. We weren't showing them (nor should we).
Split tests into separate directories (so that importgraph works).
Change-Id: I55d46b3ab33cdf7ac22436fcc2148fe04c901237
Reviewed-on: https://go-review.googlesource.com/8243
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Sorry for the oversight.
Change-Id: Ibb686dbee996b5223bd223fdd3afaab243a7a3ee
Reviewed-on: https://go-review.googlesource.com/7501
Reviewed-by: Robert Griesemer <gri@golang.org>
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
This makes it possible to find corresponding closes to receives and sends.
LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://golang.org/cl/155260043
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
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
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.
Fixesgolang/go#7839
LGTM=gri
R=gri
CC=golang-codereviews, pcc
https://golang.org/cl/93780044
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
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
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
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
This improves both performance (most calls are static) and
precision (e.g. for static calls in dead code).
Also, break callees() function into smaller ones.
R=crawshaw
CC=golang-dev
https://golang.org/cl/38740045
This removes about 5% of φ-nodes in one large program
and eliminates many zero-value constants.
(This does cause some Idents to no longer map to an ssa.Value.
This is observable in the oracle, whose tests are here updated.)
R=gri, gri
CC=golang-dev
https://golang.org/cl/26980043
Users should be familiar with the sizes of all other types.
Currently we assume amd64 (as do other parts of the oracle,
e.g. go/build tags). Will parameterize later.
R=crawshaw
CC=golang-dev, gri
https://golang.org/cl/29710043
A DebugRef associates a source expression E with an ssa.Value
V, but until now did not record whether V was the value or the
address of E. So, we would guess from the "pointerness" of
the Value, leading to confusion in some cases, e.g.
type N *N
var n N
n = &n // lvalue and rvalue are both pointers
Now we explicitly record 'IsAddress bool' in DebugRef, and
plumb this everywhere: through (*Function).ValueForExpr and
(*Program).VarValue, all the way to forming the pointer
analysis query.
Also:
- VarValue now treats each reference to a global distinctly,
just like it does for other vars. So:
var g int
func f() {
g = 1 // VarValue(g) == Const(1:int), !isAddress
print(g) // VarValue(g) == Global(g), isAddress
}
- DebugRefs are not emitted for references to predeclared
identifiers (nil, built-in).
- DebugRefs no longer prevent lifting of an Alloc var into a
register; now we update or discard the debug info.
- TestValueForExpr: improve coverage of ssa.EnclosingFunction
by putting expectations in methods and init funcs, not just
normal funcs.
- oracle: fix golden file broken by recent
(*types.Var).IsField change.
R=gri
CC=golang-dev
https://golang.org/cl/16610045
Before, we would concatenate all the init() blocks together,
resulting in incorrect treatment of a recovered panic in one
init block: the implicit return would cause the subsequent ones
to be skipped.
The result is simpler, and closer to what gc does.
The additional functions are visible in the call graph,
so some tests required updating.
R=gri
CC=crawshaw, golang-dev
https://golang.org/cl/14671044
Since rev 4c5f46cc7b9d, error messages no longer contain
"file:line:col: " prefixes, so applying stripLocation to them
is incorrect.
Also: add rationale comment to callgraph2.go test.
R=crawshaw
CC=golang-dev
https://golang.org/cl/13888044
The previous CL made the assumption that Root is the first
node, which is false for programs that import "reflect".
Reverted to the previous way: an explicit root field.
Added regression test (callgraph2) via oracle.
R=crawshaw
TBR=crawshaw
CC=golang-dev
https://golang.org/cl/13967043
Also: pointer.Analyze now returns a pointer.Result object,
containing the callgraph and the results of ssa.Value queries.
The oracle has been updated to use the new call and pointer APIs.
R=crawshaw, gri
CC=golang-dev
https://golang.org/cl/13915043
e.g. "oracle callgraph <package>"
Also: simplified error handling.
Eliminated oracle.errorf because it prepends "file:line:col: "
to the error message so the main function can't safely prepend "Error: ".
The position wasn't interesting though: it was just -pos, more or less.
R=crawshaw, dominik.honnef, r
CC=golang-dev
https://golang.org/cl/13864044
The existing standalone Query function builds an importer, ssa.Program, oracle,
and query position, executes the query and returns the result.
For clients (such as Frederik Zipp's web-based github.com/fzipp/pythia tool)
that wish to load the program once and make several queries, we now expose
these as separate operations too. Here's a client, in pseudocode:
o := oracle.New(...)
for ... {
qpos := o.ParseQueryPos(...)
res := o.Query(mode, qpos)
print result
}
NB: this is a slight deoptimisation in the one-shot case since we have to
build the entire SSA program with debug info, not just the query package,
since we now don't know the query package at that time.
The 'exact' param to ParseQueryPos needs more thought since its
ideal value is a function of the query mode. This will do for now.
Details:
- expose Oracle type, New() func and Query() method.
- expose QueryPos type and ParseQueryPos func.
- improved package doc comment.
- un-exposed the "needs" bits.
- added test.
R=crawshaw
CC=frederik.zipp, golang-dev
https://golang.org/cl/13810043
Core:
reflect.TypeOf
reflect.ValueOf
reflect.Zero
reflect.Value.Interface
Maps:
(reflect.Value).MapIndex
(reflect.Value).MapKeys
(reflect.Value).SetMapIndex
(*reflect.rtype).Elem
(*reflect.rtype).Key
+ tests:
pointer/testdata/mapreflect.go.
oracle/testdata/src/main/reflection.go.
Interface objects (T, V...) have been renamed "tagged objects".
Abstraction: we model reflect.Value similar to
interface{}---as a pointer that points only to tagged
objects---but a reflect.Value may also point to an "indirect
tagged object", one in which the payload V is of type *T not T.
These are required because reflect.Values can hold lvalues,
e.g. when derived via Field() or Elem(), though we won't use
them till we get to structs and pointers.
Solving: each reflection intrinsic defines a new constraint
and resolution rule. Because of the nature of reflection,
generalizing across types, the resolution rules dynamically
create additional complex constraints during solving, where
previously only simple (copy) constraints were created.
This requires some solver changes:
The work done before the main solver loop (to attach new
constraints to the graph) is now done before each iteration,
in processNewConstraints.
Its loop over constraints is broken into two passes:
the first handles base (addr-of) constraints,
the second handles simple and complex constraints.
constraint.init() has been inlined. The only behaviour that
varies across constraints is ptr()
Sadly this will pessimize presolver optimisations, when we get
there; such is the price of reflection.
Objects: reflection intrinsics create objects (i.e. cause
memory allocations) with no SSA operation. We will represent
them as the cgnode of the instrinsic (e.g. reflect.New), so we
extend Labels and node.data to represent objects as a product
(not sum) of ssa.Value and cgnode and pull this out into its
own type, struct object. This simplifies a number of
invariants and saves space. The ntObject flag is now
represented by obj!=nil; the other flags are moved into
object.
cgnodes are now always recorded in objects/Labels for which it
is appropriate (all but those for globals, constants and the
shared contours for functions).
Also:
- Prepopulate the flattenMemo cache to consider reflect.Value
a fake pointer, not a struct.
- Improve accessors and documentation on type Label.
- @conctypes assertions renamed @types (since dyn. types needn't be concrete).
- add oracle 'describe' test on an interface (missing, an oversight).
R=crawshaw
CC=golang-dev
https://golang.org/cl/13418048
The existing check rejected only free identifiers defined in
file scope, i.e. just imports.
+ regression test.
R=crawshaw, gri
CC=golang-dev
https://golang.org/cl/13256050
+ test.
Also:
- provide non-nil map to Importer.doImport0() to avoid a crash.
- reorganize oracle "needs" bits.
- reduce "needs" of 'freevars' and 'implements' queries by avoiding
ssa.Packages when types.Package suffices.
R=crawshaw
CC=golang-dev
https://golang.org/cl/13421046
Background: some ssa.Values represent lvalues, e.g.
var g = new(string)
the *ssa.Global g is a **string, the address of what users
think of as the global g.
Querying pts(g) returns a singleton containing the object g, a
*string. What users really want to see is what that in turn
points to, i.e. the label for the call to new().
This change now lets users make "indirect" pointer queries,
i.e. for pts(*v) where v is an ssa.Value. The oracle makes an
indirect query if the type of the ssa.Value differs from the
source expression type by a pointer, i.e. it's an lvalue.
In other words, we're hiding the fact that compilers (e.g. ssa) internally represent globals by their address.
+ Tests.
This serendipitously fixed an outstanding bug mentioned in the
describe.go
R=crawshaw
CC=golang-dev
https://golang.org/cl/13532043
Motivation: pointer analysis tools (like the oracle) want the
user to specify a set of initial packages, like 'go test'.
This change enables the user to specify a set of packages on
the command line using importer.LoadInitialPackages(args).
Each argument is interpreted as either:
- a comma-separated list of *.go source files together
comprising one non-importable ad-hoc package.
e.g. "src/pkg/net/http/triv.go" gives us [main].
- an import path, denoting both the imported package
and its non-importable external test package, if any.
e.g. "fmt" gives us [fmt, fmt_test].
Current type-checker limitations mean that only the first
import path may contribute tests: multiple packages augmented
by *_test.go files could create import cycles, which 'go test'
avoids by building a separate executable for each one.
That approach is less attractive for static analysis.
Details: (many files touched, but importer.go is the crux)
importer:
- PackageInfo.Importable boolean indicates whether
package is importable.
- un-expose Importer.Packages; expose AllPackages() instead.
- CreatePackageFromArgs has become LoadInitialPackages.
- imports() moved to util.go, renamed importsOf().
- InitialPackagesUsage usage message exported to clients.
- the package name for ad-hoc packages now comes from the
'package' decl, not "main".
ssa.Program:
- added CreatePackages() method
- PackagesByPath un-exposed, renamed 'imported'.
- expose AllPackages and ImportedPackage accessors.
oracle:
- describe: explain and workaround a go/types bug.
Misc:
- Removed various unnecessary error.Error() calls in Printf args.
R=crawshaw
CC=golang-dev
https://golang.org/cl/13579043
The typechecker uses *types.Func for functions, concrete
methods and interface methods; and *types.Var for variables
and struct fields. This change makes clear which kind of
function we're describing. (We can't do it for vars since
go/types doesn't expose enough information, yet.)
Also: add "omitempty" to one JSON field.
R=crawshaw
CC=golang-dev
https://golang.org/cl/13527044
See json.go for interface specification.
Example usage:
% oracle -format=json -mode=callgraph code.google.com/p/go.tools/cmd/oracle
+ Tests, based on (small) golden files.
Overview:
Each <query>Result structure has been "lowered" so that all
but the most trivial logic in each display() function has
been moved to the main query.
Each one now has a toJSON method that populates a json.Result
struct. Though the <query>Result structs are similar to the
correponding JSON protocol, they're not close enough to be
used directly; for example, the former contain richer
semantic entities (token.Pos, ast.Expr, ssa.Value,
pointer.Pointer, etc) whereas JSON contains only their
printed forms using Go basic types.
The choices of what levels of abstractions the two sets of
structs should have is somewhat arbitrary. We may want
richer information in the JSON output in future.
Details:
- oracle.Main has been split into oracle.Query() and the
printing of the oracle.Result.
- the display() method no longer needs an *oracle param, only
a print function.
- callees: sort the result for determinism.
- callees: compute the union across all contexts.
- callers: sort the results for determinism.
- describe(package): fixed a bug in the predicate for method
accessibility: an unexported method defined in pkg A may
belong to a type defined in package B (via
embedding/promotion) and may thus be accessible to A. New
accessibleMethods() utility fixes this.
- describe(type): filter methods by accessibility.
- added tests of 'callgraph'.
- pointer: eliminated the 'caller CallGraphNode' parameter from
pointer.Context.Call callback since it was redundant w.r.t
site.Caller().
- added warning if CGO_ENABLED is unset.
R=crawshaw
CC=golang-dev
https://golang.org/cl/13270045
+ Tests.
+ Emacs integration.
+ Emacs integration test.
+ very rudimentary Vim integration. Needs some love from a Vim user.
TODO (in follow-ups):
- More tests would be good.
We'll need to make the output order deterministic in more places.
- Documentation.
R=gri, crawshaw, dominik.honnef
CC=golang-dev
https://golang.org/cl/9502043
