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
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
