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2015-03-01all: delete C libraries and cmd/dist code that builds themRuss Cox
Change-Id: Ic66243674ac1dbf829c7523005e33611cc89ac83 Reviewed-on: https://go-review.googlesource.com/6362 Reviewed-by: Rob Pike <r@golang.org>
2015-02-26liblink: delete unused codeRuss Cox
Liblink is still needed for the linker (for a bit longer) but mostly not. Delete the unused parts. Change-Id: Ie63a7c1520dee52b17425b384943cd16262d36e3 Reviewed-on: https://go-review.googlesource.com/6110 Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-02-06liblink, cmd/ld, cmd/5l: darwin/arm supportShenghou Ma
liblink: - set dummy value for ctxt->tlsoffset. cmd/ld: - always do external linking when using cgo on darwin/arm, as our linker might not generate codesign-compatible binary. cmd/5l: - support generate ARM Mach-O binaries - add machoreloc1() that translate our internal relocation to macho relocations used by external linking. Change-Id: Ic5454aeb87009aaf8f1453ec7fe33e6da55d5f06 Reviewed-on: https://go-review.googlesource.com/3273 Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-01-30liblink: fix error message on linux for unknown TLS baseRuss Cox
headstr(Hlinux) was reporting "android", making for some confusing error messages. Change-Id: I437095bee7cb2143aa37c91cf786f3a3581ae7b9 Reviewed-on: https://go-review.googlesource.com/3513 Reviewed-by: Austin Clements <austin@google.com>
2015-01-21build: implement GOEXPERIMENT again in runtime, and add to liblinkRuss Cox
For Austin's framepointer experiment. Change-Id: I81b6f414943b3578924f853300b9193684f79bf4 Reviewed-on: https://go-review.googlesource.com/2994 Reviewed-by: Austin Clements <austin@google.com>
2015-01-14liblink: adjustments for c2go conversionRuss Cox
Mostly this is using uint32 instead of int32 for unsigned values like instruction encodings or float32 bit representations, removal of ternary operations, and removal of #defines. Delete sched9.c, because it is not compiled (it is still in the history if we ever need it). Change-Id: I68579cfea679438a27a80416727a9af932b088ae Reviewed-on: https://go-review.googlesource.com/2658 Reviewed-by: Austin Clements <austin@google.com>
2014-09-08build: adjustments for move from src/pkg to srcRuss Cox
This CL adjusts code referring to src/pkg to refer to src. Immediately after submitting this CL, I will submit a change doing 'hg mv src/pkg/* src'. That change will be too large to review with Rietveld but will contain only the 'hg mv'. This CL will break the build. The followup 'hg mv' will fix it. For more about the move, see golang.org/s/go14nopkg. LGTM=r R=r CC=golang-codereviews https://golang.org/cl/134570043
2014-08-06liblink: support big-endian properlyShenghou Ma
LGTM=rsc R=rsc, iant CC=golang-codereviews https://golang.org/cl/115300044
2014-07-21liblink: remove some gotos + other fixesRuss Cox
Rewrite gotos that violate Go's stricter rules. Use uchar* instead of char* in a few places that aren't strings. Remove dead opcross code from asm5.c. Declare regstr (in both list6 and list8) static. LGTM=minux, dave R=minux, dave CC=golang-codereviews https://golang.org/cl/113230043
2014-07-10cmd/5c, cmd/5g, cmd/5l, liblink: nacl/arm supportShenghou Ma
LGTM=dave, rsc R=rsc, iant, dave CC=golang-codereviews https://golang.org/cl/108360043
2014-07-02build: annotations and modifications for c2goRuss Cox
The main changes fall into a few patterns: 1. Replace #define with enum. 2. Add /*c2go */ comment giving effect of #define. This is necessary for function-like #defines and non-enum-able #defined constants. (Not all compilers handle negative or large enums.) 3. Add extra braces in struct initializer. (c2go does not implement the full rules.) This is enough to let c2go typecheck the source tree. There may be more changes once it is doing other semantic analyses. LGTM=minux, iant R=minux, dave, iant CC=golang-codereviews https://golang.org/cl/106860045
2014-07-02liblink, runtime: preliminary support for plan9/amd64Aram Hăvărneanu
A TLS slot is reserved by _rt0_.*_plan9 as an automatic and its address (which is static on Plan 9) is saved in the global _privates symbol. The startup linkage now is exactly like that from Plan 9 libc, and the way we access g is exactly as if we'd have used privalloc(2). Aside from making the code more standard, this change drastically simplifies it, both for 386 and for amd64, and makes the Plan 9 code in liblink common for both 386 and amd64. The amd64 runtime code was cleared of nxm assumptions, and now runs on the standard Plan 9 kernel. Note handling fixes will follow in a separate CL. LGTM=rsc R=golang-codereviews, rsc, bradfitz, dave CC=0intro, ality, golang-codereviews, jas, minux.ma, mischief https://golang.org/cl/101510049
2014-07-01all: add GOOS=androidDavid Crawshaw
As android and linux have significant overlap, and because build tags are a poor way to represent an OS target, this CL introduces an exception into go/build: linux is treated as a synonym for android when matching files. http://golang.org/s/go14android https://groups.google.com/forum/#!topic/golang-dev/P1ATVp1mun0 LGTM=rsc, minux R=golang-codereviews, mikioh.mikioh, dave, aram, minux, gobot, rsc, aram.h, elias.naur, iant CC=golang-codereviews, rsc https://golang.org/cl/105270043
2014-04-16liblink: fix incorrect hash collision in lookupRuss Cox
linklookup uses hash(name, v) as the hash table index but then only compares name to find a symbol to return. If hash(name, v1) == hash(name, v2) for v1 != v2, the lookup for v2 will return the symbol with v1. The input routines assume that each symbol is found only once, and then each symbol is added to a linked list, with the list header in the symbol. Adding a symbol to such a list multiple times short-circuits the list the second time it is added, causing symbols to be dropped. The liblink rewrite introduced an elegant, if inefficient, handling of duplicated symbols by creating a dummy symbol to read the duplicate into. The dummy symbols are named .dup with sequential version numbers. With many .dup symbols, eventually there will be a conflict, causing a duplicate list add, causing elided symbols, causing a crash when calling one of the elided symbols. The bug is old (2011) but could not have manifested until the liblink rewrite introduced this heavily duplicated symbol .dup. (See History section below.) 1. Correct the lookup function. 2. Since we want all the .dup symbols to be different, there's no point in inserting them into the table. Call linknewsym directly, avoiding the lookup function entirely. 3. Since nothing can refer to the .dup symbols, do not bother adding them to the list of functions (textp) at all. 4. In lieu of a unit test, introduce additional consistency checks to detect adding a symbol to a list multiple times. This would have caught the short-circuit more directly, and it will detect a variety of double-use bugs, including the one arising from the bad lookup. Fixes #7749. History On April 9, 2011, I submitted CL 4383047, making ld 25% faster. Much of the focus was on the hash table lookup function, and one of the changes was to remove the s->version == v comparison [1]. I don't know if this was a simple editing error or if I reasoned that same name but different v would yield a different hash slot and so the name test alone sufficed. It is tempting to claim the former, but it was probably the latter. Because the hash is an iterated multiply+add, the version ends up adding v*3ⁿ to the hash, where n is the length of the name. A collision would need x*3ⁿ ≡ y*3ⁿ (mod 2²⁴ mod 100003), or equivalently x*3ⁿ ≡ x*3ⁿ + (y-x)*3ⁿ (mod 2²⁴ mod 100003), so collisions will actually be periodic: versions x and y collide when d = y-x satisfies d*3ⁿ ≡ 0 (mod 2²⁴ mod 100003). Since we allocate version numbers sequentially, this is actually about the best case one could imagine: the collision rate is much lower than if the hash were more random. http://play.golang.org/p/TScD41c_hA computes the collision period for various name lengths. The most common symbol in the new linker is .dup, and for n=4 the period is maximized: the 100004th symbol is the first collision. Unfortunately, there are programs with more duplicated symbols than that. In Go 1.2 and before, duplicate symbols were handled without creating a dummy symbol, so this particular case for generating many duplicate symbols could not happen. Go does not use versioned symbols. Only C does; each input file gives a different version to its static declarations. There just aren't enough C files for this to come up in that context. So the bug is old but the realization of the bug is new. [1] https://golang.org/cl/4383047/diff/5001/src/cmd/ld/lib.c LGTM=minux.ma, iant, dave R=golang-codereviews, minux.ma, bradfitz, iant, dave CC=golang-codereviews, r https://golang.org/cl/87910047
2014-04-15build: remove tmp dir names from objects, support GOROOT_FINAL againRuss Cox
If we compile a generated file stored in a temporary directory - let's say /tmp/12345/work/x.c - then by default 6c stores the full path and then the pcln table in the final binary includes the full path. This makes repeated builds (using different temporary directories) produce different binaries, even if the inputs are the same. In the old 'go tool pack', the P flag specified a prefix to remove from all stored paths (if present), and cmd/go invoked 'go tool pack grcP $WORK' to remove references to the temporary work directory. We've changed the build to avoid pack as much as possible, under the theory that instead of making pack convert from .6 to .a, the tools should just write the .a directly and save a round of I/O. Instead of going back to invoking pack always, define a common flag -trimpath in the assemblers, C compilers, and Go compilers, implemented in liblink, and arrange for cmd/go to use the flag. Then the object files being written out have the shortened paths from the start. While we are here, reimplement pcln support for GOROOT_FINAL. A build in /tmp/go uses GOROOT=/tmp/go, but if GOROOT_FINAL=/usr/local/go is set, then a source file named /tmp/go/x.go is recorded instead as /usr/local/go/x.go. We use this so that we can prepare distributions to be installed in /usr/local/go without actually working in that directory. The conversion to liblink deleted all the old file name handling code, including the GOROOT_FINAL translation. Bring the GOROOT_FINAL translation back. Before this CL, using GOROOT_FINAL=/goroot make.bash: g% strings $(which go) | grep -c $TMPDIR 6 g% strings $(which go) | grep -c $GOROOT 793 g% After this CL: g% strings $(which go) | grep -c $TMPDIR 0 g% strings $(which go) | grep -c $GOROOT 0 g% (The references to $TMPDIR tend to be cgo-generated source files.) Adding the -trimpath flag to the assemblers required converting them to the new Go-semantics flag parser. The text in go1.3.html is copied and adjusted from go1.1.html, which is when we applied that conversion to the compilers and linkers. Fixes #6989. LGTM=iant R=r, iant CC=golang-codereviews https://golang.org/cl/88300045
2014-04-15liblink: introduce TLS register on 386 and amd64Russ Cox
When I did the original 386 ports on Linux and OS X, I chose to define GS-relative expressions like 4(GS) as relative to the actual thread-local storage base, which was usually GS but might not be (it might be FS, or it might be a different constant offset from GS or FS). The original scope was limited but since then the rewrites have gotten out of control. Sometimes GS is rewritten, sometimes FS. Some ports do other rewrites to enable shared libraries and other linking. At no point in the code is it clear whether you are looking at the real GS/FS or some synthesized thing that will be rewritten. The code manipulating all these is duplicated in many places. The first step to fixing issue 7719 is to make the code intelligible again. This CL adds an explicit TLS pseudo-register to the 386 and amd64. As a register, TLS refers to the thread-local storage base, and it can only be loaded into another register: MOVQ TLS, AX An offset from the thread-local storage base is written off(reg)(TLS*1). Semantically it is off(reg), but the (TLS*1) annotation marks this as indexing from the loaded TLS base. This emits a relocation so that if the linker needs to adjust the offset, it can. For example: MOVQ TLS, AX MOVQ 8(AX)(TLS*1), CX // load m into CX On systems that support direct access to the TLS memory, this pair of instructions can be reduced to a direct TLS memory reference: MOVQ 8(TLS), CX // load m into CX The 2-instruction and 1-instruction forms correspond roughly to ELF TLS initial exec mode and ELF TLS local exec mode, respectively. Liblink applies this rewrite on systems that support the 1-instruction form. The decision is made using only the operating system (and probably the -shared flag, eventually), not the link mode. If some link modes on a particular operating system require the 2-instruction form, then all builds for that operating system will use the 2-instruction form, so that the link mode decision can be delayed to link time. Obviously it is late to be making changes like this, but I despair of correcting issue 7719 and issue 7164 without it. To make sure I am not changing existing behavior, I built a "hello world" program for every GOOS/GOARCH combination we have and then worked to make sure that the rewrite generates exactly the same binaries, byte for byte. There are a handful of TODOs in the code marking kludges to get the byte-for-byte property, but at least now I can explain exactly how each binary is handled. The targets I tested this way are: darwin-386 darwin-amd64 dragonfly-386 dragonfly-amd64 freebsd-386 freebsd-amd64 freebsd-arm linux-386 linux-amd64 linux-arm nacl-386 nacl-amd64p32 netbsd-386 netbsd-amd64 openbsd-386 openbsd-amd64 plan9-386 plan9-amd64 solaris-amd64 windows-386 windows-amd64 There were four exceptions to the byte-for-byte goal: windows-386 and windows-amd64 have a time stamp at bytes 137 and 138 of the header. darwin-386 and plan9-386 have five or six modified bytes in the middle of the Go symbol table, caused by editing comments in runtime/sys_{darwin,plan9}_386.s. Fixes #7164. LGTM=iant R=iant, aram, minux.ma, dave CC=golang-codereviews https://golang.org/cl/87920043
2014-03-14liblink, runtime: make nacl/386 binaries valid.Rémy Oudompheng
They were rejected by NaCl due to AES instructions and accesses to %gs:0x8, caused by wrong tlsoffset value. LGTM=iant R=rsc, dave, iant CC=golang-codereviews https://golang.org/cl/76050044
2014-02-27all: final merge of NaCl treeRuss Cox
This CL replays the following one CL from the rsc-go13nacl repo. This is the last replay CL: after this CL the main repo will have everything the rsc-go13nacl repo did. Changes made to the main repo after the rsc-go13nacl repo branched off probably mean that NaCl doesn't actually work after this CL, but all the code is now moved over and just needs to be redebugged. --- cmd/6l, cmd/8l, cmd/ld: support for Native Client See golang.org/s/go13nacl for design overview. This CL is publicly visible but not CC'ed to golang-dev, to avoid distracting from the preparation of the Go 1.2 release. This CL and the others will be checked into my rsc-go13nacl clone repo for now, and I will send CLs against the main repo early in the Go 1.3 development. R≡khr https://golang.org/cl/15750044 --- LGTM=bradfitz, dave, iant R=dave, bradfitz, iant CC=golang-codereviews https://golang.org/cl/69040044
2014-02-09include, linlink, cmd/6l, cmd/ld: part 1 of solaris/amd64 linker changes.Shenghou Ma
rsc suggested that we split the whole linker changes into three parts. This is the first one, mostly dealing with adding Hsolaris. LGTM=iant R=golang-codereviews, iant, dave CC=golang-codereviews https://golang.org/cl/54210050
2013-12-16cmd/ld: move instruction selection + layout into compilers, assemblersRuss Cox
- new object file reader/writer (liblink/objfile.c) - remove old object file writing routines - add pcdata iterator - remove all trace of "line number stack" and "path fragments" from object files, linker (!!!) - dwarf now writes a single "compilation unit" instead of one per package This CL disables the check for chains of no-split functions that could overflow the stack red zone. A future CL will attack the problem of reenabling that check (issue 6931). This CL is just the liblink and cmd/ld changes. There are minor associated adjustments in CL 37030045. Each depends on the other. R=golang-dev, dave, iant CC=golang-dev https://golang.org/cl/39680043
2013-12-08liblink: create new library based on linker codeRuss Cox
There is an enormous amount of code moving around in this CL, but the code is the same, and it is invoked in the same ways. This CL is preparation for the new linker structure, not the new structure itself. The new library's definition is in include/link.h. The main change is the use of a Link structure to hold all the linker-relevant state, replacing the smattering of global variables. The Link structure should both make it clearer which state must be carried around and make it possible to parallelize more easily later. The main body of the linker has moved into the architecture-independent cmd/ld directory. That includes the list of known header types, so the distinction between Hplan9x32 and Hplan9x64 is removed (no other header type distinguished 32- and 64-bit formats), and code for unused formats such as ipaq kernels has been deleted. The code being deleted from 5l, 6l, and 8l reappears in liblink or in ld. Because multiple files are being merged in the liblink directory, it is not possible to show the diffs nicely in hg. The Prog and Addr structures have been unified into an architecture-independent form and moved to link.h, where they will be shared by all tools: the assemblers, the compilers, and the linkers. The unification makes it possible to write architecture-independent traversal of Prog lists, among other benefits. The Sym structures cannot be unified: they are too fundamentally different between the linker and the compilers. Instead, liblink defines an LSym - a linker Sym - to be used in the Prog and Addr structures, and the linker now refers exclusively to LSyms. The compilers will keep using their own syms but will fill out the corresponding LSyms in the Prog and Addr structures. Although code from 5l, 6l, and 8l is now in a single library, the code has been arranged so that only one architecture needs to be linked into a particular program: 5l will not contain the code needed for x86 instruction layout, for example. The object file writing code in liblink/obj.c is from cmd/gc/obj.c. Preparation for golang.org/s/go13linker work. This CL does not build by itself. It depends on 35740044 and will be submitted at the same time. R=iant CC=golang-dev https://golang.org/cl/35790044