While submitting CL 7371051 I accidentally reverted much of CL
7395052. This change restores it.
R=gri
TBR=gri
CC=golang-dev
https://golang.org/cl/7364051
The correct semantics of named result parameters and deferred
procedures cannot be implemented with the existing Ret
instruction alone, since the required sequence is:
(1) evaluate return operands and parallel-assign them to
named result parameters
(2) invoke deferred procedures
(3) load named result parameters to form result tuple.
We introduce a new 'rundefers' instruction that explicitly
invokes the deferred procedure calls, and we generate code
that follows the sequence above.
Most functions do not use deferred procedures but this cannot
be known in a single pass. So, we add an optimisation to
eliminate redundant 'rundefers'; it is piggybacked on the
existing pass done for "lifting".
Added tests.
R=gri
CC=golang-dev
https://golang.org/cl/7411043
The current code uses 64-bit pc-relative on 64-bit systems,
but in ELF linkers there is no such thing, so we cannot
express this in a .o file. Change to 32-bit.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7383055
This CL changes the encoding used for the Go symbol table,
stored in the binary and used at run time. It does not change
any of the semantics or structure: the bits are just packed
a little differently.
The comment at the top of runtime/symtab.c describes the new format.
Compared to the Go 1.0 format, the main changes are:
* Store symbol addresses as full-pointer-sized host-endian values.
(For 6g, this means addresses are 64-bit little-endian.)
* Store other values (frame sizes and so on) varint-encoded.
The second change more than compensates for the first:
for the godoc binary on OS X/amd64, the new symbol table
is 8% smaller than the old symbol table (1,425,668 down from 1,546,276).
This is a required step for allowing the host linker (gcc) to write
the final Go binary, since it will have to fill in the symbol address slots
(so the slots must be host-endian) and on 64-bit systems it may
choose addresses above 4 GB.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7403054
Actually it already worked since the spec only requires that
the one immediately preceding a for/switch/... be usable as
the target of a break or continue statement.
Added a test.
Also: allocate Function.lblocks on first use.
R=gri
CC=golang-dev
https://golang.org/cl/7365058
And fix test. Pointer to unsafe.Pointer tests nothing important...
Also identify the incorrect type: go/types.Type is a Stringer.
Also fix a couple of incorrect format verbs found by new printf checker,
now that we can run it on more files.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7385051
The previous approach desugared the ast.SelectorExpr
to make implicit field selections explicit. But:
1) it was clunky since it required allocating temporary
syntax trees.
2) it was not thread-safe since it required poking
types into the shared type map for the new ASTs.
3) the desugared syntax had no place to represent the
package lexically enclosing each implicit field
selection, so it was as if they all occurred in the
same package as the explicit field selection.
This meant unexported field names changed meaning.
This CL does what I should have done all along: just
generate the SSA instructions directly from the original
AST and the promoted field information.
Also:
- add logStack util for paired start/end log messages.
Useful for debugging crashes.
R=gri
CC=golang-dev
https://golang.org/cl/7395052
Adjust the exit status string for Plan 9.
Upon allocating >100 file descriptors, Plan 9
raises a warning. Moreover, the Go runtime for
32-bit version of Plan 9 keeps /dev/bintime
open for its implementation of runtime.nanotime().
This change accounts for these things in
TestExtraFiles.
R=rsc, rminnich, ality, bradfitz
CC=golang-dev
https://golang.org/cl/7363056
Context.Alignof/Offsetsof/Sizeof now provide means
to customize the type checker for a given platform.
- provide Context.Offsetsof to specify the
offsets of struct fields
- use the correct sizes for ints, uint, uintptrs
in constant computations
- moved all size computations into separate file
(sizes.go)
- fixed a bug with string constant slicing
R=adonovan, axwalk
CC=golang-dev
https://golang.org/cl/7363054
- imported objects don't have position information
- gc exported data contains non-exported objects at
the top-level, guard against them
- better error message when dot-imports conflict
with local declarations
R=adonovan, r
CC=golang-dev
https://golang.org/cl/7379052
pkg/go/doc: move BUG notes from Package.Bugs to the general Package.Notes field.
Removing .Bugs would break existing code so it's left in for now.
R=gri, gri, gary.burd, dsymonds, rsc, kevlar
CC=golang-dev
https://golang.org/cl/7341053
Separates the implementation of nanotime on 64-bit
version of Plan 9 from that on the 32-bit version.
The former uses a syscall.
R=rsc, rminnich, ality
CC=golang-dev
https://golang.org/cl/7379051
Functions for representing network connections as files
and vice versa, on Plan 9.
Representing network connections as files is not so
straight-forward, because a network connection on Plan 9
is represented by a host of files rather than a single
file descriptor (as is the case on UNIX). We use the
type system to distinguish between listeners and
connections, returning the control file in the former
case and the data file in the latter case.
R=rsc, rminnich, ality, akumar, bradfitz
CC=golang-dev
https://golang.org/cl/7235068
This avoids an allocation when closures are used
as "macros", in Walk idioms, or as argument to defer.
benchmark old ns/op new ns/op delta
BenchmarkSearchWrappers 1171 354 -69.77%
BenchmarkCallClosure 3 3 -12.54%
BenchmarkCallClosure1 119 7 -93.95%
BenchmarkCallClosure2 183 74 -59.18%
BenchmarkCallClosure3 187 75 -59.57%
BenchmarkCallClosure4 187 76 -58.98%
Compared to Go 1:
benchmark old ns/op new ns/op delta
BenchmarkSearchWrappers 3208 354 -88.97%
Fixes#3520.
R=daniel.morsing, bradfitz, minux.ma, dave, rsc
CC=golang-dev
https://golang.org/cl/7397056
Syscalls return `-1' on error and the representation is always
32-bits. The `$-1' literal in 64-bit assembly is always the
64-bit representation. So this change makes sure that we
always do a 32-bit comparison when checking for error.
Also makes sure that in the error case, we return a 64-bit
`-1' from runtime.seek.
Fixes the arithmetic for handling the error-string in
runtime.Syscall6.
R=golang-dev, rminnich, rsc, ality, minux.ma
CC=golang-dev
https://golang.org/cl/7399052
sigprocmask() is process-wide on darwin, so two concurrent
libcgo_sys_thread_start() can result in all signals permanently
blocked, which in particular blocks handling of nil derefs.
Fixes#4833.
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/7324058
It's accessed without mutex protection
in a different goroutine from the one that
sets it.
Also make sure that Client.Call after Client.Close
will reliably return ErrShutdown, and that clients
see ErrShutdown rather than io.EOF when appropriate.
Suggestions welcome for a way to reliably test
the mutex issue.
R=r, iant
CC=golang-dev
https://golang.org/cl/7338045
The heuristics for BitLen of a product of randomly generated primes
are wrong, and the generated candidates never match the required
size for nprimes > 10. This corner case is not expected to be used in
practice.
R=agl
CC=golang-dev
https://golang.org/cl/7397052
This CL allows to receive network interface arrival and depature
notifications through routing sockets on BSD variants. So far
Darwin doesn't support this feature.
Also does small simplification.
Update #4866.
R=golang-dev, lucio.dere, dave
CC=golang-dev
https://golang.org/cl/7365055
Plan 9 I/O preserves message boundaries, while Go
library code is written for UNIX-like operating
systems which do not. Avoid doing zero-length
writes in package os.
R=rsc, rminnich, ality, rminnich, r
CC=golang-dev
https://golang.org/cl/7406046
For now, all the callbacks from C use top-level Go functions,
so they use the equivalent C function pointer, and will continue
to do so. But perhaps some day this will be useful for calling
a Go func value (at least if the type is already known).
More importantly, the Windows callback code needs to be able
to use cgocallback_gofunc to call a Go func value.
Should fix the Windows build.
R=ken2
CC=golang-dev
https://golang.org/cl/7388049
We wrap the final '...' argument's type in types.Slice.
Added tests.
Also:
- Function.writeSignature: suppress slice '[]' when printing
variadic arg '...'.
- Eliminate Package.ImportPath field; redundant
w.r.t. Package.Types.Path.
- Use "TODO: (opt|fix)" notation more widely.
- Eliminate many redundant/stale TODOs.
R=gri
CC=golang-dev
https://golang.org/cl/7378057
Change ARM context register to R7, to get out of the way
of the register allocator during the compilation of the
prologue statements (it wants to use R0 as a temporary).
Step 2 of http://golang.org/s/go11func.
R=ken2
CC=golang-dev
https://golang.org/cl/7369048
This makes Go's quoted-printable decoder more like other
popular ones, allowing through a bare \r or \n, and also
passes through \r\n which looked like a real bug before.
Fixes#4771
R=minux.ma
CC=golang-dev
https://golang.org/cl/7300092
By appending to the wrong (always empty) list, only the last
anonymous field was being considered for promotion.
Also:
- eliminated "function-local NamedTypes" TODO; nothing to do.
- fixed Function.DumpTo: printing of anon receivers was "( T)",
now "(T)"; extracted writeSignature into own function.
- eliminated blockNames function;
thanks to BasicBlock.String, "%s" of []*BasicBlock is fine.
- extracted buildReferrers into own function.
exp/ssa can now build its own transitive closure.
R=gri
CC=golang-dev
https://golang.org/cl/7384054
runtime: add context argument to gogocall
Too many other things use AX, and at least one
(stack zeroing) cannot be moved onto a different
register. Use the less special DX instead.
Preparation for step 2 of http://golang.org/s/go11func.
Nothing interesting here, just split out so that we can
see it's correct before moving on.
R=ken2
CC=golang-dev
https://golang.org/cl/7395050
- append: nothing to do (nonsemantic change).
- delete: now performs correct conversion (+ test).
- emitCompare: nothing to do.
- emitArith (shifts): nothing to do (+ test).
- "banish untyped types": give up on that.
- real, imag: now do correct conversions.
- added comment to interp.go re zero-size values.
R=gri
CC=golang-dev
https://golang.org/cl/7391046
Revision 5e7fd762f356 has changed the output formatting in a way that
is no longer in line with the format described by the revision
ff0ade0b937b which has introduced this functionality.
When decorating the first line, instead of indenting the whole line,
the current implementation adds indentation right after the "decorate"
part and before the "log" message.
The fix addresses this issue.
R=golang-dev, iant, minux.ma, r, rsc, remyoudompheng
CC=golang-dev
https://golang.org/cl/7304094
Previously, the func structure contained an inaccurate value for
the args member and a 0 value for the locals member.
This change populates the func structure with args and locals
values computed by the compiler. The number of args was
already available in the ATEXT instruction. The number of
locals is now passed through in the new ALOCALS instruction.
This change also switches the unit of args and locals to be
bytes, just like the frame member, instead of 32-bit words.
R=golang-dev, bradfitz, cshapiro, dave, rsc
CC=golang-dev
https://golang.org/cl/7399045
The interpreter's os.Exit now triggers a special panic rather
than kill the test process. (It's semantically dubious, since
it will run deferred routines.) Interpret now returns its
exit code rather than calling os.Exit.
Also:
- disabled parts of a few $GOROOT/tests via os.Getenv("GOSSAINTERP").
- remove unnecessary 'slots' param to external functions; they
are never closures.
Most of the tests are disabled until go/types supports shifts.
They can be reenabled if you patch this workaround:
https://golang.org/cl/7312068
R=iant, bradfitz
CC=golang-dev, gri
https://golang.org/cl/7313062
By avoiding the need for self-loops following calls to panic,
we reduce the number of basic blocks considerably.
R=gri
CC=golang-dev, iant
https://golang.org/cl/7403043
Overview: Function.finish() now invokes the "lifting" pass which replaces local allocs and loads and stores to such cells by SSA registers. We use very standard machinery:
(1) we build the dominator tree for the function's control flow graph (CFG) using the "Simple" Lengauer-Tarjan algorithm. (Very "simple" in fact: even simple path compression is not yet implemented.)
In sanity-checking mode, we cross check the dominator tree against an alternative implementation using a simple iterative dataflow algorithm.
This all lives in dom.go, along with some diagnostic printing routines.
(2) we build the dominance frontier for the entire CFG using the Cytron et al algorithm. The DF is represented as a slice of slices, keyed by block index. See buildDomFrontier() in lift.go.
(3) we determine for each Alloc whether it can be lifted: is it only subject to loads and stores? If so, we traverse the iterated dominance frontier (IDF) creating φ-nodes; they are not prepended to the blocks yet.
See liftAlloc() in lift.go.
(4) we perform the SSA renaming algorithm from Cytron et al, replacing all loads to lifted Alloc cells by the value stored by the dominating store operation, and deleting the stores and allocs. See rename() in lift.go.
(5) we eliminate unneeded φ-nodes, then concatenate the remaining ones with the non-deleted instructions of the block into a new slice. We eliminate any lifted allocs from Function.Locals.
To ease reviewing, I have avoided almost all optimisations at this point, though there are many opportunities to explore. These will be easier to understand as follow-up changes.
All the existing tests (pending CL 7313062) pass. (Faster!)
Details:
"NaiveForm" BuilderMode flag suppresses all the new logic.
Exposed as 'ssadump -build=N'.
BasicBlock:
- add .Index field (b.Func[b.Index]==b), simplifying
algorithms such as Kildall-style dataflow with bitvectors.
- rename the Name field to Comment to better reflect its
reduced purpose. It now has a String() method.
- 'dom' field holds dominator tree node; private for now.
- new predIndex method.
- hasPhi is now a method
dom.go:
- domTree: a new struct for a node in a dominator tree.
- buildDomTree builds the dominator tree using the simple
variant Lengauer/Tarjan algorithm with Georgiadis'
bucket optimizations.
- sanityCheckDomTree builds dominance relation using
Kildall-style dataflow and ensures the same result is
obtained.
- printDomTreeDot prints the CFG/DomTree in GraphViz format.
blockopt.go:
- perform a mark/sweep pass to eliminate unreachable
cycles; the previous prune() opt would only eliminate
trivially dead blocks. (Needed for LT algo.)
- using .Index, fuseblocks can now delete fused blocks directly.
- delete prune().
sanity.go: more consistency checks:
- Phi with missing edge value
- local Alloc instructions must appear in Function.Locals.
- BasicBlock.Index, Func consistency
- CFG edges are all intraprocedural.
- detect nils in BasicBlock.Instrs.
- detect Function.Locals with Heap flag set.
- check fn.Blocks is nil if empty.
Also:
- Phi now has Comment field for debugging.
- Fixed bug in Select.Operands()
(took address of temporary copy of field)
- new Literal constructor zeroLiteral().
- algorithms steal private fields Alloc.index,
BasicBlock.gaps to avoid allocating maps.
- We print Function.Locals in DumpTo.
- added profiling support to ssadump.
R=iant, gri
CC=golang-dev
https://golang.org/cl/7229074
mpreinit() is called on the parent thread and with mcache (can allocate memory),
minit() is called on the child thread and can not allocate memory.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7389043
Simplifies the contract for Driver.Stmt.Close in
the process of fixing issue 3865.
Fixes#3865
Update #4459 (maybe fixes it; uninvestigated)
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7363043
Add a new, simple interface for scanning (probably textual) data,
based on a new type called Scanner. It does its own internal buffering,
so should be plausibly efficient even without injecting a bufio.Reader.
The format of the input is defined by a "split function", by default
splitting into lines. Other implemented split functions include single
bytes, single runes, and space-separated words.
Here's the loop to scan stdin as a file of lines:
s := bufio.NewScanner(os.Stdin)
for s.Scan() {
fmt.Printf("%s\n", s.Bytes())
}
if s.Err() != nil {
log.Fatal(s.Err())
}
While we're dealing with spaces, define what space means to strings.Fields.
Fixes#4802.
R=adg, rogpeppe, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/7322088
(Offsetof is a function of Alignof and Sizeof.)
- removed IntSize, PtrSize from Context (set Sizeof instead)
- GcImporter needs a Context now (it needs to have
access to Sizeof/Alignof)
- removed exported Size field from Basic (use Sizeof)
- added Offset to Field
- added Alignment, Size to Struct
R=adonovan
CC=golang-dev
https://golang.org/cl/7357046
