Permits specifying the linker to use, and trailing flags to
pass to that linker, when linking in external mode. External
mode linking is used when building a package that uses cgo, as
described in the cgo docs.
Also document -linkmode and -tmpdir.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8225043
src/cmd/gc/closure.c:133 param declared and not used: nowrap
src/cmd/gc/const.c:1139 set and not used: t1
src/cmd/ld/data.c:652 format mismatch #llx INT, arg 7
src/cmd/ld/data.c:652 format mismatch #llx INT, arg 8
src/cmd/ld/data.c:1230 set and not used: datsize
R=dave, golang-dev, lucio.dere, remyoudompheng, bradfitz
CC=golang-dev
https://golang.org/cl/8182043
This CL was written by rsc. I just tweaked 8l.
This CL adds TLS relocation to the ELF .o file we write during external linking,
so that the host linker (gcc) can decide the final location of m and g.
Similar relocations are not necessary on OS X because we use an alternate
program start-time mechanism to acquire thread-local storage.
Similar relocations are not necessary on ARM or Plan 9 or Windows
because external linking mode is not yet supported on those systems.
On almost all ELF systems, the references we use are like %fs:-0x4 or %gs:-0x4,
which we write in 6a/8a as -0x4(FS) or -0x4(GS). On Linux/ELF, however,
Xen's lack of support for this mode forced us long ago to use a two-instruction
sequence: first we load %gs:0x0 into a register r, and then we use -0x4(r).
(The ELF program loader arranges that %gs:0x0 contains a regular pointer to
that same memory location.) In order to relocate those -0x4(r) references,
the linker must know where they are. This CL adds the equivalent notation
-0x4(r)(GS*1) for this purpose: it assembles to the same encoding as -0x4(r)
but the (GS*1) indicates to the linker that this is one of those thread-local
references that needs relocation.
Thanks to Elias Naur for reminding me about this missing piece and
also for writing the test.
R=r
CC=golang-dev
https://golang.org/cl/7891047
Fixes SWIG callbacks. Previously crosscall2 was only
cgo_export_static, despite the use of two #pragma declarations
in runtime/cgo/callbacks.c.
R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/7817048
gcc generates only attr DW_AT_byte_size for DW_TAG_pointer_type of "void *",
but we used to also generate DW_AT_type pointing to imaginary unspecified
type "void", which confuses some gdb.
This change makes old Apple gdb 6.x (specifically, Apple version gdb-1515)
accepts our binary without issue like this:
(gdb) b 'main.main'
Die: DW_TAG_unspecified_type (abbrev = 10, offset = 47079)
has children: FALSE
attributes:
DW_AT_name (DW_FORM_string) string: "void"
Dwarf Error: Cannot find type of die [in module /Users/minux/go/go2.hg/bin/go]
Special thanks to Russ Cox for pointing out the problem in comment #6 of
CL 7891044.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7744051
CL 7504044 accidentally reverted part of CL 7891044 and 7552045, this CL
bring those part back.
R=golang-dev
TBR=rsc
CC=golang-dev
https://golang.org/cl/7950045
Hashtable is arranged as an array of
8-entry buckets with chained overflow.
Each bucket has 8 extra hash bits
per key to provide quick lookup within
a bucket. Table is grown incrementally.
Update #3885
Go time drops from 0.51s to 0.34s.
R=r, rsc, m3b, dave, bradfitz, khr, ugorji, remyoudompheng
CC=golang-dev
https://golang.org/cl/7504044
While we're here, downgrade DWARF to version 2.
We're not using any version 3 features, and OS X gdb
only supports version 2.
Fixes#3436.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7891044
Many thanks to Elias Naur for finding this with Valgrind on Linux.
Perhaps this is what is breaking the windows/amd64 builder.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7595044
lib9: fix runcmd, removeall, and tempdir functions
cmd/dist: Include run_plan9.c and tempdir_plan9.c
from lib9 for build, and in general consider
file names containing "plan9" for building.
cmd/ld: provide function args for the new functions
from lib9.
R=rsc, rminnich, ality, bradfitz
CC=golang-dev
https://golang.org/cl/7666043
This brings Mach-O generation more in line with ELF generation.
Having separate sections for the symtab and pclntab mean that we
can find them that way, instead of using the deprecated debug segments.
(And the host linker will keep separate sections for us, but probably
not the debug segments.)
R=ken2
CC=golang-dev
https://golang.org/cl/7688043
The sticking point on 386 has been the "PC relative" relocations
used to point the garbage collection metadata at the type info.
These aren't in the code segment, and I don't trust that the linker
isn't doing something special that would be okay in code but
not when interpreting the pointers as data (for example, a PLT
jump table would be terrible).
Solve the problem in two steps:
1. Handle "PC relative" relocations within a section internally,
so that the external linker never sees them.
2. Move the gcdata and gcbss tables into the rodata section,
where the type information lives, so that the relocations can
be handled internally.
(To answer the obvious question, we make the gc->type
references relative so that they need not be relocated
individually when generating a shared object file.)
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7629043
- Introduce MaxAlign constant and use in data layout
and ELF section header.
- Allow up to 16-byte alignment for large objects
(will help Keith's hash changes).
- Emit ELF symbol for .rathole (global /dev/null used by 8c).
- Invoke gcc with -m32/-m64 as appropriate.
- Don't invoke gcc if writing the .o file failed.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7563045
Still to do: non-linux and non-amd64.
It may work on other ELF-based amd64 systems too, but untested.
"go test -ldflags -hostobj $GOROOT/misc/cgo/test" passes.
Much may yet change, but this seems a reasonable checkpoint.
R=iant
CC=golang-dev
https://golang.org/cl/7369057
Switch to new pragma names, but leave old ones available for now.
Merge the three cgo-related sections in the .6 files into a single
cgo section.
R=golang-dev, iant, ality
CC=golang-dev
https://golang.org/cl/7424048
runtime: double-check that symbol table is sorted
If the symbol table is unsorted, the binary search in findfunc
will not find its func, which will make stack traces stop early.
When the garbage collector starts using the stack tracer,
that would be a serious problem.
The unsorted symbol addresses came from from two things:
1. The symbols in an ELF object are not necessarily sorted,
so sort them before adding them to the symbol list.
2. The __i686.get_pc_thunk.bx symbol is present in multiple
object files and was having its address adjusted multiple
times, producing an incorrect address in the symbol table.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7440044
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
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
Also:
- faster code for example extraction
- simplify handling of command documentation:
all "main" packages are treated as commands
- various minor cleanups along the way
For commands written in Go, any doc.go file containing
documentation must now be part of package main (rather
then package documentation), otherwise the documentation
won't show up in godoc (it will still build, though).
For commands written in C, documentation may still be
in doc.go files defining package documentation, but the
recommended way is to explicitly ignore those files with
a +build ignore constraint to define package main.
Fixes#4806.
R=adg, rsc, dave, bradfitz
CC=golang-dev
https://golang.org/cl/7333046
This fixes a regression introduced in changeset 98034d036d03
which added support for producing host object files.
R=rsc, minux.ma
CC=dave, golang-dev
https://golang.org/cl/7307107
Plan 9 compilers insist this but as we don't have Plan 9
builders, we'd better let gcc check the prototypes.
Inspired by CL 7289050.
R=golang-dev, seed, dave, rsc, lucio.dere
CC=akumar, golang-dev
https://golang.org/cl/7288056
Change the stack unwinding code to compensate for the dynamic
relocation of symbols.
Change the gc instruction GC_CALL to use a relative offset instead of
an absolute address.
R=golang-dev
CC=golang-dev
https://golang.org/cl/7248048
A step toward a fix for issue 4069.
To allow linking with arbitrary host object files, add a linker mode
that can generate a host object file instead of an executable.
Then the host linker can be invoked to generate the final executable.
This CL adds a new -hostobj flag that instructs the linker to write
a host object file instead of an executable.
That is, this works:
go tool 6g x.go
go tool 6l -hostobj -o x.o x.6
ld -e _rt0_amd64_linux x.o
./a.out
as does:
go tool 8g x.go
go tool 8l -hostld ignored -o x.o x.8
ld -m elf_i386 -e _rt0_386_linux x.o
./a.out
Because 5l was never updated to use the standard relocation scheme,
it will take more work to get this working on ARM.
This is a checkpoint of the basic functionality. It does not work
with cgo yet, and cgo is the main reason for the change.
The command-line interface will likely change too.
The gc linker has other information that needs to be returned to
the caller for use when invoking the host linker besides the single
object file.
R=iant, iant
CC=golang-dev
https://golang.org/cl/7060044
To allow for stdcall decorated names on Windows, two changes were needed:
1. Change the symbol versioning delimiter '@' in cgo's dynimport output to a '#', and in cmd/ld when it parses dynimports.
2. Remove the "@N" decorator from the first argument of cgo's dynimport output (PE only).
Fixes#4607.
R=minux.ma, adg, rsc
CC=golang-dev
https://golang.org/cl/7047043
The dumping routine incorrectly assumed that all incoming
symbols would be non-nil and load through it to retrieve the
symbol name. Instead of using the symbol to retrieve a name,
use the name provided by the caller.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7224043
Reference the 80386 compiler documentation now that the
documentation for the 68020 is offline.
R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7127053
Changeset f483bfe81114 moved ELF generation to the architecture
independent code and in doing so added a Section* to the Sym
type and an Elf64_Shdr* to the Section type.
This caused the Plan 9 compilers to complain about incompatible
type signatures in the many files that reference the Sym type.
R=rsc, dave
CC=golang-dev
https://golang.org/cl/7057058
There's no b in race detector.
The new flag matches the one in the go command
(go test -race math).
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/7072043
This CL adds a flag parser that matches the semantics of Go's
package flag. It also changes the linkers and compilers to use
the new flag parser.
Command lines that used to work, like
8c -FVw
6c -Dfoo
5g -I/foo/bar
now need to be split into separate arguments:
8c -F -V -w
6c -D foo
5g -I /foo/bar
The new spacing will work with both old and new tools.
The new parser also allows = for arguments, as in
6c -D=foo
5g -I=/foo/bar
but that syntax will not work with the old tools.
In addition to matching standard Go binary flag parsing,
the new flag parser generates more detailed usage messages
and opens the door to long flag names.
The recently added gc flag -= has been renamed -complete.
R=remyoudompheng, daniel.morsing, minux.ma, iant
CC=golang-dev
https://golang.org/cl/7035043
More cleanup in preparation for fixing issue 4069.
This CL replaces the three nearly identical copies of the
asmb ELF code with a single asmbelf function in elf.c.
In addition to the ELF code movement, remove the elfstr
array in favor of a simpler lookup, and identify sections by
name throughout instead of computing fragile indices.
The CL also replaces the three nearly identical copies of the
genasmsym code with a single genasmsym function in lib.c.
The ARM linker still compiles and generates binaries,
but I haven't tested the binaries. They may not work.
R=ken2
CC=golang-dev
https://golang.org/cl/7062047
The Plan 9 symbol table format defines big-endian symbol values
for portability, but we want to be able to generate an ELF object file
and let the host linker link it, as part of the solution to issue 4069.
The symbol table itself, since it is loaded into memory at run time,
must be filled in by the final host linker, using relocation directives
to set the symbol values. On a little-endian machine, the linker will
only fill in little-endian values during relocation, so we are forced
to use little-endian symbol values.
To preserve most of the original portability of the symbol table
format, we make the table itself say whether it uses big- or
little-endian values. If the table begins with the magic sequence
fe ff ff ff 00 00
then the actual table begins after those six bytes and contains
little-endian symbol values. Otherwise, the table is in the original
format and contains big-endian symbol values. The magic sequence
looks like an "end of table" entry (the fifth byte is zero), so legacy
readers will see a little-endian table as an empty table.
All the gc architectures are little-endian today, so the practical
effect of this CL is to make all the generated tables little-endian,
but if a big-endian system comes along, ld will not generate
the magic sequence, and the various readers will fall back to the
original big-endian interpretation.
R=ken2
CC=golang-dev
https://golang.org/cl/7066043
A few USED(xxx) additions and a couple of deletions of variable
initialisations that go unused. One questionable correction,
mirrored in 8l/asm.c, where the result of invocation of a function
shouldn't be used.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6736054
The 0-length part is fine, but some callers that write 0 bytes
also pass nil as the data pointer, and the Plan 9 kernel kills the
process with 'invalid address in sys call' in that case.
R=ken2
CC=golang-dev
https://golang.org/cl/6862051
In order to add these, we need to be able to find references
to such types that already exist in the binary. To do that, introduce
a new linker section holding a list of the types corresponding to
arrays, chans, maps, and slices.
To offset the storage cost of this list, and to simplify the code,
remove the interface{} header from the representation of a
runtime type. It was used in early versions of the code but was
made obsolete by the kind field: a switch on kind is more efficient
than a type switch.
In the godoc binary, removing the interface{} header cuts two
words from each of about 10,000 types. Adding back the list of pointers
to array, chan, map, and slice types reintroduces one word for
each of about 500 types. On a 64-bit machine, then, this CL *removes*
a net 156 kB of read-only data from the binary.
This CL does not include the needed support for precise garbage
collection. I have created issue 4375 to track that.
This CL also does not set the 'algorithm' - specifically the equality
and copy functions - for a new array correctly, so I have unexported
ArrayOf for now. That is also part of issue 4375.
Fixes#2339.
R=r, remyoudompheng, mirtchovski, iant
CC=golang-dev
https://golang.org/cl/6572043
This is an experiment in static analysis of Go programs
to understand which struct fields a program might use.
It is not part of the Go language specification, it must
be enabled explicitly when building the toolchain,
and it may be removed at any time.
After building the toolchain with GOEXPERIMENT=fieldtrack,
a specific field can be marked for tracking by including
`go:"track"` in the field tag:
package pkg
type T struct {
F int `go:"track"`
G int // untracked
}
To simplify usage, only named struct types can have
tracked fields, and only exported fields can be tracked.
The implementation works by making each function begin
with a sequence of no-op USEFIELD instructions declaring
which tracked fields are accessed by a specific function.
After the linker's dead code elimination removes unused
functions, the fields referred to by the remaining
USEFIELD instructions are the ones reported as used by
the binary.
The -k option to the linker specifies the fully qualified
symbol name (such as my/pkg.list) of a string variable that
should be initialized with the field tracking information
for the program. The field tracking string is a sequence
of lines, each terminated by a \n and describing a single
tracked field referred to by the program. Each line is made
up of one or more tab-separated fields. The first field is
the name of the tracked field, fully qualified, as in
"my/pkg.T.F". Subsequent fields give a shortest path of
reverse references from that field to a global variable or
function, corresponding to one way in which the program
might reach that field.
A common source of false positives in field tracking is
types with large method sets, because a reference to the
type descriptor carries with it references to all methods.
To address this problem, the CL also introduces a comment
annotation
//go:nointerface
that marks an upcoming method declaration as unavailable
for use in satisfying interfaces, both statically and
dynamically. Such a method is also invisible to package
reflect.
Again, all of this is disabled by default. It only turns on
if you have GOEXPERIMENT=fieldtrack set during make.bash.
R=iant, ken
CC=golang-dev
https://golang.org/cl/6749064
compiler_rt introduces a weak and hidden symbol compilerrt_abort_impl
into our pre-linked _all.o object, we have to handle it.
Fixes#4273.
R=iant, rsc, r
CC=golang-dev
https://golang.org/cl/6783050
Check for specific, important misalignment in garbage collector.
Not a complete fix for issue 599 but an important workaround.
Update #599.
R=golang-dev, iant, dvyukov
CC=golang-dev
https://golang.org/cl/6641049
1. R_ARM_CALL can also be used to call a PLT entry
2. add support for R_ARM_PC24 and R_ARM_JUMP24
3. refactor, remove D_PLT32 in favor of D_CALL
Fixes#4006.
R=rsc, dave
CC=fullung, golang-dev
https://golang.org/cl/6622057
Use explicit IntSize constant instead of 4.
This CL does not change the meaning of int, but it should make
the eventual change of the meaning of int on amd64 a bit
smoother.
Update #2188.
R=ken, dave
CC=golang-dev
https://golang.org/cl/6554076
OpenBSD now requires ELF binaries to have a PT_NOTE that identifies
it as an OpenBSD binary. Refactor the existing NetBSD ELF signature
code and implement support for OpenBSD ELF signatures.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6489131
We use pkg path instead of file name (which contains $WORK) in section symbols names.
R=golang-dev, fullung, rsc, iant
CC=golang-dev
https://golang.org/cl/6445085
This is the second part of a bigger change that adds data race detection feature:
https://golang.org/cl/6456044
This change makes the linker emit dependency on runtime/race package when supplied with -b flag.
R=rsc, minux.ma
CC=golang-dev
https://golang.org/cl/6488074
This fixes a problem with ELF tools thinking they know the
format of the symbol table, as we do not use any of the
standard formats for that table.
This change will probably annoy the Plan 9 users, but I
believe there are other incompatibilities already that mean
they have to use a Go-specific nm.
Fixes#3473.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/6500117
To make it more compliant.
This won't affect the behavior of running on OABI-only kernels.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/6475044
The last fix was wrong w.r.t C's operator precedence,
and it also failed to really skip the NONE relocation.
The offending R_386_NONE relocation is a absolute
relocation in section .eh_frame.
TBR=golang-dev
CC=golang-dev
https://golang.org/cl/6463058
PAX systems are Linux systems that are more paranoid about memory permissions.
These flags tell them to relax when running Go binaries.
Fixes#47.
R=iant
CC=golang-dev
https://golang.org/cl/6326054
16 seems pretty standard on x86 for function entry.
I don't know if ARM would benefit, so I used just 4
(single instruction alignment).
This has a minor absolute effect on the current timings.
The main hope is that it will make them more consistent from
run to run.
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17 4222117400 4140739800 -1.93%
BenchmarkFannkuch11 3462631800 3259914400 -5.85%
BenchmarkGobDecode 20887622 20620222 -1.28%
BenchmarkGobEncode 9548772 9384886 -1.72%
BenchmarkGzip 151687 150333 -0.89%
BenchmarkGunzip 8742 8741 -0.01%
BenchmarkJSONEncode 62730560 65210990 +3.95%
BenchmarkJSONDecode 252569180 249394860 -1.26%
BenchmarkMandelbrot200 5267599 5273394 +0.11%
BenchmarkRevcomp25M 980813500 996013800 +1.55%
BenchmarkTemplate 361259100 360620840 -0.18%
R=ken2
CC=golang-dev
https://golang.org/cl/6244066
On NetBSD a cgo enabled binary has more than 32 sections - bump NSECTS
so that we can actually link them successfully.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6261052
Plan 9 versions for amd64 have 2 megabyte pages.
This also fixes the logic for 32-bit vs 64-bit Plan 9,
making 64-bit the default, and adds logic to generate
a symbols table.
R=golang-dev, rsc, rminnich, ality, 0intro
CC=golang-dev, john
https://golang.org/cl/6218046
CL 5823055 removed a line introduced in Linux/ARM cgo support.
Because readsym() now returns nil for "$a", "$d" mapping symbols,
no matter the settings of `needSym', we still have to guard against
them in ldelf().
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/6220073
Introduce a newsym() to cmd/lib.c to add a symbol but don't add
them to hash table.
Introduce a new bit flag SHIDDEN and bit mask SMASK to handle hidden
and/or local symbols in ELF symbol tables. Though we still need to order
the symbol table entries correctly.
Fix for issue 3261 comment #9.
For CL 5822049.
R=iant, rsc
CC=golang-dev
https://golang.org/cl/5823055
ld -r could generate multiple section symbols for the same section,
but with different values, we have to take that into account.
Fixes#3322.
Part of issue 3261.
For CL 5822049.
R=golang-dev, iant, rsc, iant
CC=golang-dev
https://golang.org/cl/5823059
Some newer Linux distributions (Ubuntu ARM at least) use a new multiarch
directory organization, where dynamic linker is no longer in the hardcoded
path in our linker.
For example, Ubuntu 12.04 ARM hardfloat places its dynamic linker at
/lib/arm-linux-gnueabihf/ld-linux.so.3
Ref: http://lackof.org/taggart/hacking/multiarch/
Also, to support Debian GNU/kFreeBSD as a FreeBSD variant, we need this capability, so it's part of issue 3533.
This CL add a new pragma (#pragma dynlinker "path") to cc.
R=iant, rsc
CC=golang-dev
https://golang.org/cl/6086043
Part 1 of CL 5601044 (cgo: Linux/ARM support)
Limitation: doesn't support thumb library yet.
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/5991065
1. consistent usage section (go tool xxx)
2. reformat cmd/ld document with minor correction
document which -H flags are valid on which ld
document -d flag can't be used on Windows.
document -Hwindowsgui
R=golang-dev, r, rsc
CC=golang-dev
https://golang.org/cl/5782043
We were not aligning the code size,
so read-only data, which follows in the same
segment, could be arbitrarily misaligned.
Fixes#2506.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/5693055
cc: add #pragma textflag to set it
runtime: mark mheap to go into noptr-bss.
remove special case in garbage collector
Remove the ARM from.flag field created by CL 5687044.
The DUPOK flag was already in p->reg, so keep using that.
Otherwise test/nilptr.go creates a very large binary.
Should fix the arm build.
Diagnosed by minux.ma; replacement for CL 5690044.
R=golang-dev, minux.ma, r
CC=golang-dev
https://golang.org/cl/5686060
The garbage collector can avoid scanning this section, with
reduces collection time as well as the number of false positives.
Helps a little bit with issue 909, but certainly does not solve it.
R=ken2
CC=golang-dev
https://golang.org/cl/5671099
unsafe: delete Typeof, Reflect, Unreflect, New, NewArray
Part of issue 2955 and issue 2968.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5650069
To allow these types as map keys, we must fill in
equal and hash functions in their algorithm tables.
Structs or arrays that are "just memory", like [2]int,
can and do continue to use the AMEM algorithm.
Structs or arrays that contain special values like
strings or interface values use generated functions
for both equal and hash.
The runtime helper func runtime.equal(t, x, y) bool handles
the general equality case for x == y and calls out to
the equal implementation in the algorithm table.
For short values (<= 4 struct fields or array elements),
the sequence of elementwise comparisons is inlined
instead of calling runtime.equal.
R=ken, mpimenov
CC=golang-dev
https://golang.org/cl/5451105
Equality on structs will require arbitrary code for type equality,
so change algorithm in type data from uint8 to table pointer.
In the process, trim top-level map structure from
104/80 bytes (64-bit/32-bit) to 24/12.
Equality on structs will require being able to call code generated
by the Go compiler, and C code has no way to access Go return
values, so change the hash and equal algorithm functions to take
a pointer to a result instead of returning the result.
R=ken
CC=golang-dev
https://golang.org/cl/5453043
This CL grew the archive file name length from 16 to 64:
changeset: 909:58574851d792
user: Russ Cox <rsc@golang.org>
date: Mon Oct 20 13:53:56 2008 -0700
Back then, every x.go file in a package became an x.6 file
in the archive. It was important to be able to allow the
use of long Go source file names, hence the increase in size.
Today, all Go source files compile into a single _go_.6 file
regardless of their names, so the archive file name length
no longer needs to be long. The longer name causes some
problems on Plan 9, where the native archive format is the
same but with 16-byte names, so revert back to 16.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5333050
Move string table to the end of the __LINKEDIT segment.
This change allows Apple's codesign(1) utility to successfully sign
Go binaries, as long as they don't contain DWARF data (-w flag to
8l/6l). This is because codesign(1) expects the string table to be
the last part of the file.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5271050
The Windows signtool.exe thinks our binaries are 'invalid
Win32 programs' unless the PE linker version field is 3.0
or greater.
This minor change makes it possible to successfully sign
gc-built binaries on Windows.
R=golang-dev, alex.brainman, rsc
CC=golang-dev
https://golang.org/cl/5268045
The map implementation was using the C idiom of using
a pointer just past the end of its table as a limit pointer.
Unfortunately, the garbage collector sees that pointer as
pointing at the block adjacent to the map table, pinning
in memory a block that would otherwise be freed.
Fix by making limit pointer point at last valid entry, not
just past it.
Reviewed by Mike Burrows.
R=golang-dev, bradfitz, lvd, r
CC=golang-dev
https://golang.org/cl/5158045
The Go version has 64 character long section names; originally,
in Plan 9, the limit was 16. To provide compatibility, this
change allows the input length to be either the target length
or the earlier option. The section name is extended with spaces
where required.
This has been tested to work without regressions in the
Go environment, testing the older alternative has not been
possible yet.
R=rsc
CC=golang-dev
https://golang.org/cl/4650071
The EXTERN lines in elf.h already define these.
That's not a problem for most C compilers, but
apparently it is for some copies of the OS X linker.
Fixes#2167.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/4936044
ld/data.c:
. Format specifier with corresponding cast to cater for all
architectures (llux and vlong).
ld/ldelf.c:
ld/ldmacho.c:
. Missing "pn" argument in diag() calls.
ld/ldpe.c:
. Dropped "sym->sectnum" in diag() call.
. Typo in a comment.
ld/lib.h:
. Added varargck pragma for "O".
R=rsc
CC=golang-dev
https://golang.org/cl/4749042
The dynamic ELF sections were pointing to the proper data,
but that data was already owned by the rodata and text sections.
Some ELF references explicitly prohibit multiple sections from
owning the same data, and strip behaves accordingly.
The data for these sections was moved out and their ranges are
now owned by their respective sections. This change makes strip
happy both with and without -s being provided at link time.
A test was added in debug/elf to ensure there are no regressions
on this area in the future.
Fixes#1242.
Fixes#2022.
NOTE: Tested on Linux amd64/386/arm only.
R=rsc
CC=golang-dev
https://golang.org/cl/4808043
Reduces number of write+seek's from 88516 to 2080
when linking godoc with 6l.
Thanks to Alex Brainman for pointing out the
many small writes.
R=golang-dev, r, alex.brainman, robert.hencke
CC=golang-dev
https://golang.org/cl/4743043
The gosymtab and gopclntab sections were pointing to the proper
data, but that data was already owned by the rodata section.
Some ELF references explicitly prohibit multiple sections from
owning the same data, and strip behaves accordingly.
The data for these sections was moved to after rodata, and the
gosymtab and gopclntab sections now own their respective ranges.
This change makes strip happy both with and without -s being
provided at link time. Note that it won't remove these sections
because they are still allocated, and that's by design since
they are necessary at runtime for generating proper backtraces
and similar introspection operations.
Unlike the previous behavior, -s will now maintain zero-sized
gosymtab and gopclntab sections. This makes the implementation
slightly cleaner.
Fixes#1242.
NOTE: Tested on Linux amd64/386/arm only.
R=ality, rsc
CC=golang-dev
https://golang.org/cl/4639077
This prevents ld from generating zeroed symtab entries for
sections that aren't going to be generated because dynamic
linkage has been disabled (-d was used or no dynamic libs
were seen). Even though they were not explicitly added by
doelf, the section creation process was making them
reachable again.
The windows head is being disconsidered for this because
apparently it's not taking into account debug['d'].
This makes elflint 0.1% happier.
R=golang-dev, rsc, gustavo
CC=golang-dev
https://golang.org/cl/4638050
Once these changes are effected, it is possible to construct
"8l" native on a (386?) Plan 9 system, albeit with assistance
from modules such as mkfiles that are not (yet) included in any
public patches.
8l/asm.c:
. Corrected some format qualifiers.
8l/list.c:
. Cast a print() argument to (int) to match the given format.
It may be possible to change the format (%R), but I have not
looked into it.
8l/obj.c:
. Removed some unused code.
8l/span.c:
. Removed unnecessary incrementation on "bp".
. Corrected some format qualifiers.
ld/data.c:
. Corrected some format qualifiers.
. Cast print argument to (int): used as field size.
. Use braces to suppress warning about empty if() statements.
ld/dwarf.c:
. Trivial spelling mistake in comment.
ld/ldelf.c:
. Added USED() statements to silence warnings.
. Dropped redundant address (&) operators.
. corrected some format qualifiers.
. Cast to (int) for switch selection variable.
ld/macho.c:
. Added USED() statements to silence warnings.
ld/ldpe.c:
. Added USED() statements to silence warnings.
. More careful use of "sect" variable.
. Corrected some format qualifiers.
. Removed redundant assignments.
. Minor fix dropped as it was submitted separately.
ld/pe.c:
. Dropped <time.h> which is now in <u.h>.
. Dropped redundant address (&) operators.
. Added a missing variable initialisation.
ld/symtab.c:
. Added USED() statements to silence warnings.
. Removed redundant incrementation.
. Corrected some format qualifiers.
All the above have been tested against a (very) recent release
and do not seem to trigger any regressions.
All review suggestions have been incorporated.
R=rsc
CC=golang-dev
https://golang.org/cl/4633043
The "elf.h" header changes involve only comments, the released
Plan 9 C preprocessing function does not cope with multiline
comments following the #define keyword. All multiline comments
have been moved to the line above the associated definition.
Sigh! Fixing the Plan 9 compiler is not an option.
<time.h> does not exist in the Plan 9 Native library. I have
moved it from src/cmd/ld/pe.h to include/u.h. RSC correctly points
out that this copy of <u.h> is not the one used to compile the
Go release on Plan 9 platforms.
R=golang-dev
CC=golang-dev, rsc
https://golang.org/cl/4574042
Makes it possible for older tools like objdump to find the filenames,
fixes objdump -d -l --start-address=0x400c00 --stop-address=0x400c36 6.out
fixes#1950
R=rsc
CC=golang-dev
https://golang.org/cl/4609043
I started looking at this code because the nm in GNU
binutils was ignoring the first symbol in the .symtab
section. Apparently, the System V ABI reserves the
first entry and requires all fields inside to be set
to zero.
The list of changes is as follows:
· reserve the first symbol entry (as noted above)
· fix the section indices for .data and .bss symbols
· factor out common code for Elf32 and Elf64
· remove the special case for elfsymo in [568]l/asm.c:/^asmb
· add the "etext" symbol in 6l
· add static symbols
R=rsc
CC=golang-dev
https://golang.org/cl/4524075
These changes are not particularly invasive and have been tested
as broadly as possible.
8l/l.h:
- #pragma varargck: added some, removed duplicates.
ld/dwarf.c:
- As Plan 9 has no NULL, changed all occurrences to nil.
- Added USED(size); where necessary.
- Added (void) argument in definition of finddebugruntimepath().
- Plan 9 compiler was complaining about multiple
assignments, repeaired by breaking up the commands.
- Correction: havedynamic = 1; restored.
ld/go.c:
- Needed USED(file); in two functions.
- Removed unused assignments flagged by the Plan 9 compiler.
ld/lib.c:
- Replaced unlink() with remove() which seems available everywhere.
- Removed USED(c4); and USED(magic) no longer required.
- Removed code flagged as unused by the Plan 9 compiler.
- Added attributes to a number of format strings.
R=rsc
CC=golang-dev
https://golang.org/cl/4435047
Reenable dwarf output on Mac.
Was writing headers but no actual dwarf data.
Fixes#1877 (accidentally).
Workaround for issue 1878.
R=lvd
CC=golang-dev
https://golang.org/cl/4515139
This was causing a panic in the reflect package
since type.* pointers with their low bits set are
assumed to have certain flags set that disallow
the use of reflection.
Thanks to Pavel and Taru for help tracking down
this bug.
R=rsc, paulzhol, taruti
CC=golang-dev
https://golang.org/cl/4511041
This change will allow to generate valid executable,
even if rsc disables dwarf generation, as it happend
at revision 9a64273f9d68.
R=rsc
CC=golang-dev, lvd, vcc
https://golang.org/cl/4425066
Static symbols were not being marked as such.
I also made the 'z' symbols use the first byte of
the name instead of an explicit NUL so that if
the symbol table format is ever changed, the only
place that would need updating is addhist().
R=rsc
CC=golang-dev
https://golang.org/cl/4366047
The list elements are already being allocated out of a
single memory buffer. We can drop the Link* pointer
following and the memory it requires, replacing it with
index operations.
The change also keeps a channel from containing a pointer
back into its own allocation block, which would create a
cycle. Blocks involved in cycles are not guaranteed to be
finalized properly, and channels depend on finalizers to
free OS-level locks on some systems. The self-reference
was keeping channels from being garbage collected.
runtime-gdb.py will need to be updated in order to dump
the content of buffered channels with the new data structure.
Fixes#1676.
R=ken2, r
CC=golang-dev
https://golang.org/cl/4411045
The ld time was dominated by symbol table processing, so
* increase hash table size
* emit fewer symbols in gc (just 1 per string, 1 per type)
* add read-only lookup to avoid creating spurious symbols
* add linked list to speed whole-table traversals
Breaks dwarf generator (no idea why), so disable dwarf.
Reduces time for 6l to link godoc by 25%.
R=ken2
CC=golang-dev
https://golang.org/cl/4383047
Fixes the broken linux/amd64 build.
The symbol table, itself a symbol, was having
its size rounded up to the nearest word boundary.
If the rounding add >7 zero bytes then it confused
the debug/gosym symbol table parser. So you've
got a 1/8 chance to hit the bug on an amd64 system.
Just started in the recent change because I fixed
the rounding to round to word boundary instead
of to 4-byte boundary.
R=r
CC=golang-dev
https://golang.org/cl/4241056
Much of the bulk of Go binaries is the symbol tables,
which give a name to every C string, Go string,
and reflection type symbol. These names are not worth
much other than seeing what's where in a binary.
This CL deletes all those names from the symbol table,
instead aggregating the symbols into contiguous blocks
and giving them the names "string.*", "go.string.*", and "type.*".
Before:
$ 6nm $(which godoc.old) | sort | grep ' string\.' | tail -10
59eda4 D string."aa87ca22be8b05378eb1c71...
59ee08 D string."b3312fa7e23ee7e4988e056...
59ee6c D string."func(*token.FileSet, st...
59eed0 D string."func(io.Writer, []uint8...
59ef34 D string."func(*tls.Config, *tls....
59ef98 D string."func(*bool, **template....
59effc D string."method(p *printer.print...
59f060 D string."method(S *scanner.Scann...
59f12c D string."func(*struct { begin in...
59f194 D string."method(ka *tls.ecdheRSA...
$
After:
$ 6nm $(which godoc) | sort | grep ' string\.' | tail -10
5e6a30 D string.*
$
Those names in the "Before" are truncated for the CL.
In the real binary they are the complete string, up to
a certain length, or else a unique identifier.
The same applies to the type and go.string symbols.
Removing the names cuts godoc by more than half:
-rwxr-xr-x 1 rsc rsc 9153405 2011-03-07 23:19 godoc.old
-rwxr-xr-x 1 rsc rsc 4290071 2011-03-07 23:19 godoc
For what it's worth, only 80% of what's left gets loaded
into memory; the other 20% is dwarf debugging information
only ever accessed by gdb:
-rwxr-xr-x 1 rsc rsc 3397787 2011-03-07 23:19 godoc.nodwarf
R=r, cw
CC=golang-dev
https://golang.org/cl/4245072
The pointer will eventually let us find *T given T.
This CL just makes room for it, always storing a zero.
R=r, r2
CC=golang-dev
https://golang.org/cl/4221046
A reference to the address of weak.foo resolves at link time
to the address of the symbol foo if foo would end up in the
binary anyway, or to zero if foo would not be in the binary.
For example:
int xxx = 1;
int yyy = 2;
int weak·xxx;
int weak·yyy;
void main·main(void) {
runtime·printf("%p %p %p\n", &xxx, &weak·xxx, &weak·yyy);
}
prints the same non-nil address twice, then 0 (because yyy is not
referenced so it was dropped from the binary).
This will be used by the reflection tables.
R=iant
CC=golang-dev
https://golang.org/cl/4223044
Fix problems found.
On amd64, various library routines had bigger
stack frames than expected, because large function
calls had been added.
runtime.assertI2T: nosplit stack overflow
120 assumed on entry to runtime.assertI2T
8 after runtime.assertI2T uses 112
0 on entry to runtime.newTypeAssertionError
-8 on entry to runtime.morestack01
runtime.assertE2E: nosplit stack overflow
120 assumed on entry to runtime.assertE2E
16 after runtime.assertE2E uses 104
8 on entry to runtime.panic
0 on entry to runtime.morestack16
-8 after runtime.morestack16 uses 8
runtime.assertE2T: nosplit stack overflow
120 assumed on entry to runtime.assertE2T
16 after runtime.assertE2T uses 104
8 on entry to runtime.panic
0 on entry to runtime.morestack16
-8 after runtime.morestack16 uses 8
runtime.newselect: nosplit stack overflow
120 assumed on entry to runtime.newselect
56 after runtime.newselect uses 64
48 on entry to runtime.printf
8 after runtime.printf uses 40
0 on entry to vprintf
-8 on entry to runtime.morestack16
runtime.selectdefault: nosplit stack overflow
120 assumed on entry to runtime.selectdefault
56 after runtime.selectdefault uses 64
48 on entry to runtime.printf
8 after runtime.printf uses 40
0 on entry to vprintf
-8 on entry to runtime.morestack16
runtime.selectgo: nosplit stack overflow
120 assumed on entry to runtime.selectgo
0 after runtime.selectgo uses 120
-8 on entry to runtime.gosched
On arm, 5c was tagging functions NOSPLIT that should
not have been, like the recursive function printpanics:
printpanics: nosplit stack overflow
124 assumed on entry to printpanics
112 after printpanics uses 12
108 on entry to printpanics
96 after printpanics uses 12
92 on entry to printpanics
80 after printpanics uses 12
76 on entry to printpanics
64 after printpanics uses 12
60 on entry to printpanics
48 after printpanics uses 12
44 on entry to printpanics
32 after printpanics uses 12
28 on entry to printpanics
16 after printpanics uses 12
12 on entry to printpanics
0 after printpanics uses 12
-4 on entry to printpanics
R=r, r2
CC=golang-dev
https://golang.org/cl/4188061
