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2025-10-08cmd/internal/obj: fix Link.Diag printf errorsAlan Donovan
go1.26's vet printf checker can associate the printf-wrapper property with local vars and struct fields if they are assigned from a printf-like func literal (CL 706635). This leads to better detection of mistakes. Change-Id: I604be1e200aa1aba75e09d4f36ab68c1dba3b8a3 Reviewed-on: https://go-review.googlesource.com/c/go/+/710195 Auto-Submit: Alan Donovan <adonovan@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
2025-05-05Revert "cmd/compile: allow all of the preamble to be preemptible"Keith Randall
This reverts commits 3f3782feed6e0726ddb08afd32dad7d94fbb38c6 (CL 648518) b386b628521780c048af14a148f373c84e687b26 (CL 668475) Fixes #73542 Change-Id: I218851c5c0b62700281feb0b3f82b6b9b97b910d Reviewed-on: https://go-review.googlesource.com/c/go/+/670055 Reviewed-by: Keith Randall <khr@google.com> Auto-Submit: Keith Randall <khr@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-04-25cmd/compile: allow all of the preamble to be preemptibleKeith Randall
We currently make some parts of the preamble unpreemptible because it confuses morestack. See comments in the code. Instead, have morestack handle those weird cases so we can remove unpreemptible marks from most places. This CL makes user functions preemptible everywhere if they have no write barriers (at least, on x86). In cmd/go the fraction of functions that need preemptible markings drops from 82% to 36%. Makes the cmd/go binary 0.3% smaller. Update #35470 Change-Id: Ic83d5eabfd0f6d239a92e65684bcce7e67ff30bb Reviewed-on: https://go-review.googlesource.com/c/go/+/648518 Auto-Submit: Keith Randall <khr@google.com> Reviewed-by: Keith Randall <khr@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
2024-11-13cmd/compile, cmd/link: add FIPS verification supportRuss Cox
For FIPS init-time code+data verification, we need to arrange to put the FIPS symbols into contiguous regions of the executable and then record those sections along with the expected checksum. The cmd/internal/obj changes identify the FIPS symbols and give them distinguished types, which the linker then places in contiguous regions. The linker also writes out information to use at run time to find the FIPS sections, along with the expected hash. See cmd/internal/obj/fips.go and cmd/link/internal/ld/fips.go for more details. The code is disabled in this commit. CL 625998 and 625999 adds tests. CL 626000 enables the code. For #69536. Change-Id: I48da6db94bc0bea7428c43d4abcf999527bccfcd Reviewed-on: https://go-review.googlesource.com/c/go/+/625997 Auto-Submit: Russ Cox <rsc@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2024-11-07cmd/internal/objabi, cmd/link: introduce SymKind helper methodsRuss Cox
These will be necessary when we start using the new FIPS symbols. Split into a separate CL so that these refactoring changes can be tested separate from any FIPS-specific changes. Passes golang.org/x/tools/cmd/toolstash/buildall. Change-Id: I73e5873fcb677f1f572f0668b4dc6f3951d822bc Reviewed-on: https://go-review.googlesource.com/c/go/+/625996 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Auto-Submit: Russ Cox <rsc@golang.org>
2023-09-01cmd/internal/obj: simplify filename handlingMatthew Dempsky
The old Go object file format used linker symbols like "gofile..foo" to record references to the filename "foo". But the current object file format has a dedicated section for file names, so we don't need these useless prefixes anymore. Also, change DWARF generation to pass around the src.Pos directly, rather than the old file symbols, which it just turned back into a file index before writing out anyway. Finally, directly record the FileIndex into src.PosBase, so that we can skip the map lookups. Change-Id: Ia4a5ebfa95da271f2522e45befdb9f137c16d373 Reviewed-on: https://go-review.googlesource.com/c/go/+/523378 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Auto-Submit: Matthew Dempsky <mdempsky@google.com>
2023-08-29cmd/internal/obj: add Func type to replace "curfn any"Matthew Dempsky
This adds a modicum of type safety to these APIs, which are otherwise quite confusing to follow. Change-Id: I268a9a1a99a47dcfef6dc1e9e5be13673af3fb85 Reviewed-on: https://go-review.googlesource.com/c/go/+/523396 Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Matthew Dempsky <mdempsky@google.com>
2023-08-29cmd/internal/{dwarf,obj}: stop substituting "" with pkgprefixMatthew Dempsky
cmd/asm and cmd/compile now always create symbols with the appropriate package prefixes, so cmd/internal/dwarf and cmd/internal/obj can stop worrying about qualifying names itself. Change-Id: I9aee5d759bf0d41a61722c777e7f66fce957e79e Reviewed-on: https://go-review.googlesource.com/c/go/+/523338 Reviewed-by: Cherry Mui <cherryyz@google.com> Auto-Submit: Matthew Dempsky <mdempsky@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-08-29cmd/internal/obj: tweak implicit {ArgsPointerMaps,ArgInfo} behaviorMatthew Dempsky
This CL changes cmd/internal/obj to also implicitly set ArgsPointerMaps and ArgInfo for assembly functions that are explicitly package qualified (e.g., "pkg·name", not just "·name"). This is a prerequisite for changing cmd/asm to stop emitting `"".`-prefixed symbol names. Change-Id: I4e14bc24c87cf4d7114a7aed9beaf0c8d1f9c07f Reviewed-on: https://go-review.googlesource.com/c/go/+/523335 Auto-Submit: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Matthew Dempsky <mdempsky@google.com>
2023-08-29cmd: simplify some handling of package pathsMatthew Dempsky
We have obj.Link.Pkgpath, so we don't need to pass it redundantly in places where we already have an *obj.Link. Also, renaming the parser's "compilingRuntime" field to "allowABI", to match the "AllowAsmABI" name used by objabi.LookupPkgSpecial. Finally, push the handling of GOEXPERIMENT_* flags up to cmd/asm's main entry point, by simply appending them to flags.D. Change-Id: I6ada134522b0cbc90d35bcb145fbe045338fefb7 Reviewed-on: https://go-review.googlesource.com/c/go/+/523297 Run-TryBot: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Auto-Submit: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-04-21internal/abi, runtime, cmd: merge PCDATA_* and FUNCDATA_* consts into ↵Austin Clements
internal/abi We also rename the constants related to unsafe-points: currently, they follow the same naming scheme as the PCDATA table indexes, but are not PCDATA table indexes. For #59670. Change-Id: I06529fecfae535be5fe7d9ac56c886b9106c74fd Reviewed-on: https://go-review.googlesource.com/c/go/+/485497 Run-TryBot: Austin Clements <austin@google.com> Reviewed-by: David Chase <drchase@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Austin Clements <austin@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
2023-04-21internal/abi, runtime, cmd: merge funcFlag_* consts into internal/abiAustin Clements
For #59670. Change-Id: Ie784ba4dd2701e4f455e1abde4a6bfebee4b1387 Reviewed-on: https://go-review.googlesource.com/c/go/+/485496 Reviewed-by: David Chase <drchase@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Austin Clements <austin@google.com> Auto-Submit: Austin Clements <austin@google.com>
2023-04-05cmd/internal/obj: generate SEH aux symbols for windows/amd64qmuntal
This CL updates the Go compiler so it generate SEH unwind info [1] as a function auxiliary symbol when building for windows/amd64. A follow up CL will teach the Go linker how to assemble these codes into the PE .xdata section. Updates #57302 [1] https://learn.microsoft.com/en-us/cpp/build/exception-handling-x64#struct-unwind_info Change-Id: I40ae0437bfee326c1a67c2b5e1496f0bf3ecea17 Reviewed-on: https://go-review.googlesource.com/c/go/+/461749 Reviewed-by: Davis Goodin <dagood@microsoft.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com> Run-TryBot: Quim Muntal <quimmuntal@gmail.com>
2023-02-06cmd/internal/obj: flag init functions in object fileThan McIntosh
Introduce a flag in the object file indicating whether a given function corresponds to a compiler-generated (not user-written) init function, such as "os.init" or "syscall.init". Add code to the compiler to fill in the correct value for the flag, and add support to the loader package in the linker for testing the flag. The new loader API is currently unused, but will be needed in the next CL in this stack. Updates #2559. Updates #36021. Updates #14840. Change-Id: Iea7ad2adda487e4af7a44f062f9817977c53b394 Reviewed-on: https://go-review.googlesource.com/c/go/+/463855 Reviewed-by: Cherry Mui <cherryyz@google.com> Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-12-05cmd/asm: improve assembler error messagesKeith Randall
Provide file/line numbers for errors when we have them. Make the assembler error text closer to the equivalent errors from the compiler. Abort further processing when we come across errors. Fixes #53994 Change-Id: I4d6a037d6d713c1329923fce4c1189b5609f3660 Reviewed-on: https://go-review.googlesource.com/c/go/+/455276 Reviewed-by: Keith Randall <khr@google.com> Run-TryBot: Keith Randall <khr@google.com> Auto-Submit: Keith Randall <khr@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-10-31cmd/internal/obj: cleanup linkgetlineFromPosMichael Pratt
Make linkgetlineFromPos and getFileIndexAndLine methods on Link, and give the former a more descriptive name. The docs are expanded to make it more clear that these are final file/line visible in programs. In getFileSymbolAndLine use ctxt.InnermostPos instead of ctxt.PosTable direct, which makes it more clear that we want the semantics of InnermostPos. Change-Id: I7c3d344dec60407fa54b191be8a09c117cb87dd0 Reviewed-on: https://go-review.googlesource.com/c/go/+/446301 Reviewed-by: Cherry Mui <cherryyz@google.com> Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-10-14cmd/compile,cmd/link,runtime: add start line numbers to func metadataMichael Pratt
This adds the function "start line number" to runtime._func and runtime.inlinedCall objects. The "start line number" is the line number of the func keyword or TEXT directive for assembly. Subtracting the start line number from PC line number provides the relative line offset of a PC from the the start of the function. This helps with source stability by allowing code above the function to move without invalidating samples within the function. Encoding start line rather than relative lines directly is convenient because the pprof format already contains a start line field. This CL uses a straightforward encoding of explictly including a start line field in every _func and inlinedCall. It is possible that we could compress this further in the future. e.g., functions with a prologue usually have <line of PC 0> == <start line>. In runtime.test, 95% of functions have <line of PC 0> == <start line>. According to bent, this is geomean +0.83% binary size vs master and -0.31% binary size vs 1.19. Note that //line directives can change the file and line numbers arbitrarily. The encoded start line is as adjusted by //line directives. Since this can change in the middle of a function, `line - start line` offset calculations may not be meaningful if //line directives are in use. For #55022. Change-Id: Iaabbc6dd4f85ffdda294266ef982ae838cc692f6 Reviewed-on: https://go-review.googlesource.com/c/go/+/429638 Run-TryBot: Michael Pratt <mpratt@google.com> Auto-Submit: Michael Pratt <mpratt@google.com> Reviewed-by: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
2022-05-16cmd/compile: set LocalPkg.Path to -p flagMatthew Dempsky
Since CL 391014, cmd/compile now requires the -p flag to be set the build system. This CL changes it to initialize LocalPkg.Path to the provided path, rather than relying on writing out `"".` into object files and expecting cmd/link to substitute them. However, this actually involved a rather long tail of fixes. Many have already been submitted, but a few notable ones that have to land simultaneously with changing LocalPkg: 1. When compiling package runtime, there are really two "runtime" packages: types.LocalPkg (the source package itself) and ir.Pkgs.Runtime (the compiler's internal representation, for synthetic references). Previously, these ended up creating separate link symbols (`"".xxx` and `runtime.xxx`, respectively), but now they both end up as `runtime.xxx`, which causes lsym collisions (notably inittask and funcsyms). 2. test/codegen tests need to be updated to expect symbols to be named `command-line-arguments.xxx` rather than `"".foo`. 3. The issue20014 test case is sensitive to the sort order of field tracking symbols. In particular, the local package now sorts to its natural place in the list, rather than to the front. Thanks to David Chase for helping track down all of the fixes needed for this CL. Updates #51734. Change-Id: Iba3041cf7ad967d18c6e17922fa06ba11798b565 Reviewed-on: https://go-review.googlesource.com/c/go/+/393715 Reviewed-by: David Chase <drchase@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2021-10-04cmd, runtime: eliminate runtime.no_pointers_stackmapJosh Bleecher Snyder
runtime.no_pointers_stackmap is an odd beast. It is defined in a Go file, populated by assembly, used by the GC, and its address is magic used by async pre-emption to ascertain whether a routine was implemented in assembly. A subsequent change will force all GC data into the go.func.* linker symbol. runtime.no_pointers_stackmap is GC data, so it must go there. Yet it also needs to go into rodata, for the runtime address trick. This change eliminates it entirely. Replace the runtime address check with the newly introduced asm funcflag. Handle the assembly macro as magic, similarly to our handling of go_args_stackmap. This allows the no_pointers_stackmap to be identical in all ways to other gclocals stackmaps, including content-addressability. Change-Id: Id2f20a262cfab0719beb88e6342984ec4b196268 Reviewed-on: https://go-review.googlesource.com/c/go/+/353672 Trust: Josh Bleecher Snyder <josharian@gmail.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
2021-10-04cmd, runtime: mark assembly routines in FuncFlagsJosh Bleecher Snyder
There's no good way to ascertain at runtime whether a function was implemented in assembly. The existing workaround doesn't play nicely with some upcoming linker changes. This change introduces an explicit marker for routines implemented in assembly. This change doesn't use the new bit anywhere, it only introduces it. Change-Id: I4051dc0afc15b260724a04b9d18aeeb94911bb29 Reviewed-on: https://go-review.googlesource.com/c/go/+/353671 Trust: Josh Bleecher Snyder <josharian@gmail.com> Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
2021-05-03cmd/compile: add traceback argument info to ABI0 assembly functionsCherry Zhang
For ABI0 assembly functions that have Go declarations, generate traceback argument info and attach it to the assembly functions. So we can print argument in tracebacks if e.g. assembly function panics. Only do this for ABI0 functions, as for ABIInternal assembly functions it is likely that they never spill arguments to memory. Change-Id: I7e601ccd9aded5e6af2f02be975bf81ff9948f4d Reviewed-on: https://go-review.googlesource.com/c/go/+/315870 Trust: Cherry Zhang <cherryyz@google.com> Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-14cmd/internal/obj: don't emit args_stackmap for ABIInternal asm funcsThan McIntosh
The compiler currently emits an "*.args_stackmap" symbol for all bodyless functions, so that asm functions will have the proper stack map. At the moment the code in the compiler that emits args_stackmap assumes ABI0; to avoid misleading stackmaps, turn off args_stackmap generation for non-ABI0 asm functions. Updates #40724. Change-Id: Ia5e3528d56da5fb107e799bd658e52496ba4a331 Reviewed-on: https://go-review.googlesource.com/c/go/+/309790 Trust: Than McIntosh <thanm@google.com> Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-04-05cmd/compile: untangle Wrapper and ABIWrapper flagsCherry Zhang
Currently, there are Wrapper and ABIWrapper attributes. Wrapper is set when compiler generates an wrapper function (e.g. method wrapper). ABIWrapper is set when compiler generates an ABI wrapper. It also sets Wrapper flag for ABI wrappers. Currently, they have the following meanings: - Wrapper flag hides the frame from (normal) traceback. - Wrapper flag enables special panic+recover adjustment, so it can correctly recover when a wrapper function is deferred. - ABIWrapper flag disables the panic+recover adjustment, because we never defer an ABI wrapper that can recover. This CL changes them to: - Both Wrapper and ABIWrapper flags hide the frame from (normal) traceback. (Setting one is enough.) - Wrapper flag enables special panic+recover adjustment. ABIWrapper flag no longer has effect on this. This makes it clearer if we do want an ABI wrapper that also does the panic+recover adjustment. In the old mechanism we'd have to unset ABIWrapper flag, even if the function is actually an ABI wrapper. In the new mechanism we just need to set both ABIWrapper and Wrapper flags. Updates #40724. Change-Id: I7fbc83f85d23676dc94db51dfda63dcacdf1fc19 Reviewed-on: https://go-review.googlesource.com/c/go/+/307235 Trust: Cherry Zhang <cherryyz@google.com> Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Austin Clements <austin@google.com>
2021-03-16cmd/asm: when dynamic linking, reject code that uses a clobbered R15Keith Randall
The assember uses R15 as scratch space when assembling global variable references in dynamically linked code. If the assembly code uses the clobbered value of R15, report an error. The user is probably expecting some other value in that register. Getting rid of the R15 use isn't very practical (we could save a register to a field in the G maybe, but that gets cumbersome). Fixes #43661 Change-Id: I43f848a3d8b8a28931ec733386b85e6e9a42d8ff Reviewed-on: https://go-review.googlesource.com/c/go/+/283474 Trust: Keith Randall <khr@golang.org> Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-02-19cmd/asm, cmd/link, runtime: introduce FuncInfo flag bitsRuss Cox
The runtime traceback code has its own definition of which functions mark the top frame of a stack, separate from the TOPFRAME bits that exist in the assembly and are passed along in DWARF information. It's error-prone and redundant to have two different sources of truth. This CL provides the actual TOPFRAME bits to the runtime, so that the runtime can use those bits instead of reinventing its own category. This CL also adds a new bit, SPWRITE, which marks functions that write directly to SP (anything but adding and subtracting constants). Such functions must stop a traceback, because the traceback has no way to rederive the SP on entry. Again, the runtime has its own definition which is mostly correct, but also missing some functions. During ordinary goroutine context switches, such functions do not appear on the stack, so the incompleteness in the runtime usually doesn't matter. But profiling signals can arrive at any moment, and the runtime may crash during traceback if it attempts to unwind an SP-writing frame and gets out-of-sync with the actual stack. The runtime contains code to try to detect likely candidates but again it is incomplete. Deriving the SPWRITE bit automatically from the actual assembly code provides the complete truth, and passing it to the runtime lets the runtime use it. This CL is part of a stack adding windows/arm64 support (#36439), intended to land in the Go 1.17 cycle. This CL is, however, not windows/arm64-specific. It is cleanup meant to make the port (and future ports) easier. Change-Id: I227f53b23ac5b3dabfcc5e8ee3f00df4e113cf58 Reviewed-on: https://go-review.googlesource.com/c/go/+/288800 Trust: Russ Cox <rsc@golang.org> Trust: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
2020-12-22[dev.regabi] cmd/compile,cmd/link: initial support for ABI wrappersThan McIntosh
Add compiler support for emitting ABI wrappers by creating real IR as opposed to introducing ABI aliases. At the moment these are "no-op" wrappers in the sense that they make a simple call (using the existing ABI) to their target. The assumption here is that once late call expansion can handle both ABI0 and the "new" ABIInternal (register version), it can expand the call to do the right thing. Note that the runtime contains functions that do not strictly follow the rules of the current Go ABI0; this has been handled in most cases by treating these as ABIInternal instead (these changes have been made in previous patches). Generation of ABI wrappers (as opposed to ABI aliases) is currently gated by GOEXPERIMENT=regabi -- wrapper generation is on by default if GOEXPERIMENT=regabi is set and off otherwise (but can be turned on using "-gcflags=all=-abiwrap -ldflags=-abiwrap"). Wrapper generation currently only workd on AMD64; explicitly enabling wrapper for other architectures (via the command line) is not supported. Also in this patch are a few other command line options for debugging (tracing and/or limiting wrapper creation). These will presumably go away at some point. Updates #27539, #40724. Change-Id: I1ee3226fc15a3c32ca2087b8ef8e41dbe6df4a75 Reviewed-on: https://go-review.googlesource.com/c/go/+/270863 Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Trust: Than McIntosh <thanm@google.com>
2020-10-30cmd/compile: delete register maps, completelyCherry Zhang
Remove go115ReduceLiveness feature gating flag, along with code that only needed when go115ReduceLiveness is false. Change-Id: I7571913cc74cbd17b330a0ee0160fefc9eeee66e Reviewed-on: https://go-review.googlesource.com/c/go/+/264338 Trust: Cherry Zhang <cherryyz@google.com> Run-TryBot: Cherry Zhang <cherryyz@google.com> Reviewed-by: Austin Clements <austin@google.com>
2020-10-16cmd/internal/obj: move LSym.Func into LSym.ExtraRuss Cox
This creates space for a different kind of extension field in LSym without making the struct any larger. (There are many LSym, so we care about keeping the struct small.) Change-Id: Ib16edb9e15f54c2a7351c8b875e19684058711e5 Reviewed-on: https://go-review.googlesource.com/c/go/+/243943 Trust: Russ Cox <rsc@golang.org> Run-TryBot: Russ Cox <rsc@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-08-13cmd/compile: remove AttrSeenGlobl (use AttrOnList instead)Than McIntosh
Minor cleanup: remove the symbol attribute AttrSeenGlobal, since it is redundant with the existing attribute AttrOnList (no need to have what amounts to a separate flag for checking the same property). Change-Id: Ia269b64de37c2bb4a2314bbecf3d2091c6d57424 Reviewed-on: https://go-review.googlesource.com/c/go/+/239477 Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2020-08-03[dev.link] move FuncID creation into the compiler/assemblerJeremy Faller
Leaving creation of the funcID till the linker requires the linker to load the function and file names into memory. Moving these into the compiler/assembler prevents this. This work is a step towards moving all func metadata into the compiler. Change-Id: Iebffdc5a909adbd03ac263fde3f4c3d492fb1eac Reviewed-on: https://go-review.googlesource.com/c/go/+/244024 Run-TryBot: Jeremy Faller <jeremy@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: Austin Clements <austin@google.com>
2020-07-08[dev.link] cmd/compile: mark stmp and stkobj symbols as staticThan McIntosh
Mark compiler-generated ".stmp_%d" and "<fn>.stkobj" symbols as AttrStatic, so as to tell the linker that they do not need to be inserted into its name lookup tables. Change-Id: I59ffd11659b2c54c2d0ad41275d05c3f919e3b88 Reviewed-on: https://go-review.googlesource.com/c/go/+/240497 Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-05-08[dev.link] all: merge branch 'master' into dev.linkCherry Zhang
Clean merge. Change-Id: I6a39d0c00c7455ad0ce3dfe582a5f16d85857f51
2020-05-06cmd/internal/obj, runtime: preempt & restart some instruction sequencesCherry Zhang
On some architectures, for async preemption the injected call needs to clobber a register (usually REGTMP) in order to return to the preempted function. As a consequence, the PC ranges where REGTMP is live are not preemptible. The uses of REGTMP are usually generated by the assembler, where it needs to load or materialize a large constant or offset that doesn't fit into the instruction. In those cases, REGTMP is not live at the start of the instruction sequence. Instead of giving up preemption in those cases, we could preempt it and restart the sequence when resuming the execution. Basically, this is like reissuing an interrupted instruction, except that here the "instruction" is a Prog that consists of multiple machine instructions. For this to work, we need to generate PC data to mark the start of the Prog. Currently this is only done for ARM64. TODO: the split-stack function prologue is currently not async preemptible. We could use this mechanism, preempt it and restart at the function entry. Change-Id: I37cb282f8e606e7ab6f67b3edfdc6063097b4bd1 Reviewed-on: https://go-review.googlesource.com/c/go/+/208126 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2020-05-04[dev.link] cmd: delete old object supportCherry Zhang
We are not going to merge to master until Go 1.16 cycle. The old object support can go now. Change-Id: I93e6f584974c7749d0a0c2e7a96def35134dc566 Reviewed-on: https://go-review.googlesource.com/c/go/+/231918 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>
2020-03-23[dev.link] cmd/internal/obj: restore old DWARF symbol handlingCherry Zhang
When old object file format is used, serialize DWARF symbols in the old way. Change-Id: I73a97f10bba367ac29c52f8f3d0f8f3b34a42523 Reviewed-on: https://go-review.googlesource.com/c/go/+/224624 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>
2020-03-20[dev.link] cmd/compile, cmd/link: move DWARF info sym to anonymous aux dataThan McIntosh
Switch the primary subprogram die DWARF symbol emitted by the compiler from named+dupOK to anonymous aux. This should help performance wise by not having to add these symbols to the linker's symbol name lookup tables. Change-Id: Idf66662b8bf60b3dee9a55e6cd5137b24a9f5ab6 Reviewed-on: https://go-review.googlesource.com/c/go/+/223669 Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-12[dev.link] cmd/link: demote DWARF line symbols to anonymous auxThan McIntosh
Convert DWARF .debug_line symbols to anonymous aux syms, so as to save space in object files and reduce the number of symbols that have to be added to the linker's lookup tables. Change-Id: I5b350f036e21a7a7128cb08148ab7c243aaf0d0b Reviewed-on: https://go-review.googlesource.com/c/go/+/223018 Reviewed-by: Jeremy Faller <jeremy@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-03-12[dev.link] cmd/link: demote dwarf {range,loc} sub-symbols to auxThan McIntosh
When the compiler emits DWARF for a function F, in addition to the text symbol for F, it emits a set of sibling or child symbols that carry the various DWARF bits for F (for example, go.info.F, go.ranges.F, go.loc.F, and so on). Prior to the linker modernization work, name lookup was the way you made your way from a function symbol to one of its child DWARF symbols. We now have a new mechanism (aux symbols), so there is really no need for the DWARF sub-symbols to be named or to be dupok. This patch converts DWARF "range" and "loc" sub-symbols to be pure aux syms: unnamed, and connected to their parent text symbol only via aux data. This should presumably have performance benefits in that we add fewer symbols to the linker lookup tables. Other related DWARF sub-symbols (ex: go.line.*) will be handled in a subsequent patch. Change-Id: Iae3ec2d42452962d4afc1df4a1bd89ccdeadc6e4 Reviewed-on: https://go-review.googlesource.com/c/go/+/222673 Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: Jeremy Faller <jeremy@golang.org> Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-03-10[dev.link] cmd/asm: new -p option, changes to DWARF generationThan McIntosh
Adds a new "-p" option to the assembler, for specifying the import path of the package being compiled. DWARF generation is now conditional on having a valid package path -- if we don't know the package path, then don't emit DWARF. This is intended to lay the groundwork for removing the various "patchDWARFname" hacks in the linker. Change-Id: I5f8315c0881791eb8fe1f2ba32f5bb0ae76f6b98 Reviewed-on: https://go-review.googlesource.com/c/go/+/222718 Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: Jeremy Faller <jeremy@golang.org>
2019-11-27cmd/internal/obj: mark split-stack prologue nonpreemptibleCherry Zhang
When there are both a synchronous preemption request (by clobbering the stack guard) and an asynchronous one (by signal), the running goroutine may observe the synchronous request first in stack bounds check, and go to the path of calling morestack. If the preemption signal arrives at this point before the call to morestack, the goroutine will be asynchronously preempted, entering the scheduler. When it is resumed, the scheduler clears the preemption request, unclobbers the stack guard. But the resumed goroutine will still call morestack, as it is already on its way. morestack will, as there is no preemption request, double the stack unnecessarily. If this happens multiple times, the stack may grow too big, although only a small amount is actually used. To fix this, we mark the stack bounds check and the call to morestack async-nonpreemptible, starting after the memory instruction (mostly a load, on x86 CMP with memory). Not done for Wasm as it does not support async preemption. Fixes #35470. Change-Id: Ibd7f3d935a3649b80f47539116ec9b9556680cf2 Reviewed-on: https://go-review.googlesource.com/c/go/+/207350 Reviewed-by: David Chase <drchase@google.com>
2019-11-27cmd/internal/obj, runtime: use register map to mark unsafe pointsCherry Zhang
Currently we use stack map index -2 to mark unsafe points, i.e. PC ranges that is not safe for async preemption. This has a problem: it cannot mark CALL instructions, because for stack scan a valid stack map index is needed. This CL switches to use register map index for marking unsafe points instead, which does not conflict with stack scan and can be applied on CALL instructions. This is necessary as next CL will mark call to morestack nonpreemptible. For #35470. Change-Id: I357bf26c996e1fee1e7eebe4e6bb07d62930d3f7 Reviewed-on: https://go-review.googlesource.com/c/go/+/207349 Reviewed-by: David Chase <drchase@google.com>
2019-11-07cmd/internal/obj/arm64: mark unsafe pointsCherry Zhang
For async preemption, we will be using REGTMP as a temporary register in injected call on ARM64, which will clobber it. So any code that uses REGTMP is not safe for async preemption. In the assembler backend, we expand a Prog to multiple machine instructions and use REGTMP as a temporary register if necessary. These need to be marked unsafe. In fact, most of the multi-instruction Progs use REGTMP, so we mark all of them, except ones that are whitelisted. Change-Id: I6e97805a13950e3b693fb606d77834940ac3722e Reviewed-on: https://go-review.googlesource.com/c/go/+/203460 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2019-09-26cmd/compile: remove isStmt symbol from FuncInfoJeremy Faller
As promised in CL 188238, removing the obsolete symbol. Here are the latest stats. This is baselined at "e53edafb66" with only these changes applied, run on magna.cam. The linker looks straight better (in memory and speed). There is still a change I'm working on walking the progs to generate the debug_lines data in the compiler. That will likely result in a compiler speedup. name old time/op new time/op delta Template 324ms ± 3% 317ms ± 3% -2.07% (p=0.043 n=10+10) Unicode 142ms ± 4% 144ms ± 3% ~ (p=0.393 n=10+10) GoTypes 1.05s ± 2% 1.07s ± 2% +1.59% (p=0.019 n=9+9) Compiler 4.09s ± 2% 4.11s ± 1% ~ (p=0.218 n=10+10) SSA 12.5s ± 1% 12.7s ± 1% +1.00% (p=0.035 n=10+10) Flate 199ms ± 7% 203ms ± 5% ~ (p=0.481 n=10+10) GoParser 245ms ± 3% 246ms ± 5% ~ (p=0.780 n=9+10) Reflect 672ms ± 4% 688ms ± 3% +2.42% (p=0.015 n=10+10) Tar 280ms ± 4% 284ms ± 4% ~ (p=0.123 n=10+10) XML 379ms ± 4% 381ms ± 2% ~ (p=0.529 n=10+10) LinkCompiler 1.16s ± 4% 1.12s ± 2% -3.03% (p=0.001 n=10+9) ExternalLinkCompiler 2.28s ± 3% 2.23s ± 3% -2.51% (p=0.011 n=8+9) LinkWithoutDebugCompiler 686ms ± 9% 667ms ± 2% ~ (p=0.277 n=9+8) StdCmd 14.1s ± 1% 14.0s ± 1% ~ (p=0.739 n=10+10) name old user-time/op new user-time/op delta Template 604ms ±23% 564ms ± 7% ~ (p=0.661 n=10+9) Unicode 429ms ±40% 418ms ±37% ~ (p=0.579 n=10+10) GoTypes 2.43s ±12% 2.51s ± 7% ~ (p=0.393 n=10+10) Compiler 9.22s ± 3% 9.27s ± 3% ~ (p=0.720 n=9+10) SSA 26.3s ± 3% 26.6s ± 2% ~ (p=0.579 n=10+10) Flate 328ms ±19% 333ms ±12% ~ (p=0.842 n=10+9) GoParser 387ms ± 5% 378ms ± 9% ~ (p=0.356 n=9+10) Reflect 1.36s ±20% 1.43s ±21% ~ (p=0.631 n=10+10) Tar 469ms ±12% 471ms ±21% ~ (p=0.497 n=9+10) XML 685ms ±18% 698ms ±19% ~ (p=0.739 n=10+10) LinkCompiler 1.86s ±10% 1.87s ±11% ~ (p=0.968 n=10+9) ExternalLinkCompiler 3.20s ±13% 3.01s ± 8% -5.70% (p=0.046 n=8+9) LinkWithoutDebugCompiler 1.08s ±15% 1.09s ±20% ~ (p=0.579 n=10+10) name old alloc/op new alloc/op delta Template 36.3MB ± 0% 36.4MB ± 0% +0.26% (p=0.000 n=10+10) Unicode 28.5MB ± 0% 28.5MB ± 0% ~ (p=0.165 n=10+10) GoTypes 120MB ± 0% 121MB ± 0% +0.29% (p=0.000 n=9+10) Compiler 546MB ± 0% 548MB ± 0% +0.32% (p=0.000 n=10+10) SSA 1.84GB ± 0% 1.85GB ± 0% +0.49% (p=0.000 n=10+10) Flate 22.9MB ± 0% 23.0MB ± 0% +0.25% (p=0.000 n=10+10) GoParser 27.8MB ± 0% 27.9MB ± 0% +0.25% (p=0.000 n=10+8) Reflect 77.5MB ± 0% 77.7MB ± 0% +0.27% (p=0.000 n=9+9) Tar 34.5MB ± 0% 34.6MB ± 0% +0.23% (p=0.000 n=10+10) XML 44.2MB ± 0% 44.4MB ± 0% +0.32% (p=0.000 n=10+10) LinkCompiler 239MB ± 0% 230MB ± 0% -3.86% (p=0.000 n=10+10) ExternalLinkCompiler 243MB ± 0% 243MB ± 0% +0.22% (p=0.000 n=10+10) LinkWithoutDebugCompiler 164MB ± 0% 155MB ± 0% -5.45% (p=0.000 n=10+10) name old allocs/op new allocs/op delta Template 371k ± 0% 372k ± 0% +0.44% (p=0.000 n=10+10) Unicode 340k ± 0% 340k ± 0% +0.05% (p=0.000 n=10+10) GoTypes 1.32M ± 0% 1.32M ± 0% +0.46% (p=0.000 n=10+10) Compiler 5.34M ± 0% 5.37M ± 0% +0.59% (p=0.000 n=10+10) SSA 17.6M ± 0% 17.7M ± 0% +0.63% (p=0.000 n=10+10) Flate 233k ± 0% 234k ± 0% +0.48% (p=0.000 n=10+10) GoParser 309k ± 0% 310k ± 0% +0.40% (p=0.000 n=10+10) Reflect 964k ± 0% 969k ± 0% +0.54% (p=0.000 n=10+10) Tar 346k ± 0% 348k ± 0% +0.48% (p=0.000 n=10+9) XML 424k ± 0% 426k ± 0% +0.51% (p=0.000 n=10+10) LinkCompiler 751k ± 0% 645k ± 0% -14.13% (p=0.000 n=10+10) ExternalLinkCompiler 1.79M ± 0% 1.69M ± 0% -5.30% (p=0.000 n=10+10) LinkWithoutDebugCompiler 217k ± 0% 222k ± 0% +2.02% (p=0.000 n=10+10) name old object-bytes new object-bytes delta Template 547kB ± 0% 559kB ± 0% +2.17% (p=0.000 n=10+10) Unicode 215kB ± 0% 216kB ± 0% +0.60% (p=0.000 n=10+10) GoTypes 1.99MB ± 0% 2.03MB ± 0% +2.02% (p=0.000 n=10+10) Compiler 7.86MB ± 0% 8.07MB ± 0% +2.73% (p=0.000 n=10+10) SSA 26.4MB ± 0% 27.2MB ± 0% +3.27% (p=0.000 n=10+10) Flate 337kB ± 0% 343kB ± 0% +2.02% (p=0.000 n=10+10) GoParser 432kB ± 0% 441kB ± 0% +2.11% (p=0.000 n=10+10) Reflect 1.33MB ± 0% 1.36MB ± 0% +1.87% (p=0.000 n=10+10) Tar 477kB ± 0% 487kB ± 0% +2.24% (p=0.000 n=10+10) XML 617kB ± 0% 632kB ± 0% +2.33% (p=0.000 n=10+10) name old export-bytes new export-bytes delta Template 18.5kB ± 0% 18.5kB ± 0% ~ (all equal) Unicode 7.92kB ± 0% 7.92kB ± 0% ~ (all equal) GoTypes 35.0kB ± 0% 35.0kB ± 0% ~ (all equal) Compiler 109kB ± 0% 109kB ± 0% +0.09% (p=0.000 n=10+10) SSA 137kB ± 0% 137kB ± 0% +0.03% (p=0.000 n=10+10) Flate 4.89kB ± 0% 4.89kB ± 0% ~ (all equal) GoParser 8.49kB ± 0% 8.49kB ± 0% ~ (all equal) Reflect 11.4kB ± 0% 11.4kB ± 0% ~ (all equal) Tar 10.5kB ± 0% 10.5kB ± 0% ~ (all equal) XML 16.7kB ± 0% 16.7kB ± 0% ~ (all equal) name old text-bytes new text-bytes delta HelloSize 760kB ± 0% 760kB ± 0% ~ (all equal) CmdGoSize 10.8MB ± 0% 10.8MB ± 0% ~ (all equal) name old data-bytes new data-bytes delta HelloSize 10.7kB ± 0% 10.7kB ± 0% ~ (all equal) CmdGoSize 312kB ± 0% 312kB ± 0% ~ (all equal) name old bss-bytes new bss-bytes delta HelloSize 122kB ± 0% 122kB ± 0% ~ (all equal) CmdGoSize 146kB ± 0% 146kB ± 0% ~ (all equal) name old exe-bytes new exe-bytes delta HelloSize 1.11MB ± 0% 1.13MB ± 0% +1.10% (p=0.000 n=10+10) CmdGoSize 14.9MB ± 0% 15.0MB ± 0% +0.77% (p=0.000 n=10+10) Change-Id: I42e6087cd6231dbdcfff5464e46d373474e455e1 Reviewed-on: https://go-review.googlesource.com/c/go/+/192417 Reviewed-by: Austin Clements <austin@google.com> Run-TryBot: Austin Clements <austin@google.com>
2019-09-24cmd/compile: generate debug_lines in compilerJeremy Faller
This is mostly a copy-paste jobs from the linker to generate the debug information in the compiler instead of the linker. The new data is inserted into the debug line numbers symbol defined in CL 188238. Generating the debug information BEFORE deadcode results in one subtle difference, and that is that the state machine needs to be reset at the end of every function's debug line table. The reasoning is that generating the table AFTER dead code allows the producer and consumer of the table to agree on the state of the state machine, and since these blocks will (eventually) be concatenated in the linker, we don't KNOW the state of the state machine unless we reset it. So, generateDebugLinesSymbol resets the state machine at the end of every function. Right now, we don't do anything with this line information, or the file table -- we just populate the symbols. Change-Id: If9103eda6cc5f1f7a11e7e1a97184a060a4ad7fb Reviewed-on: https://go-review.googlesource.com/c/go/+/188317 Run-TryBot: Jeremy Faller <jeremy@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2019-09-23cmd/compile: add new symbol for debug line numbersJeremy Faller
This is broken out from: CL 187117 This new symbol will be populated by the compiler and contain debug line information that's currently generated in the linker. One might say it's sad to create a new symbol, but this symbol will replace the isStmt symbols. Testing: Ran go build -toolexec 'toolstash -cmp' Change-Id: If8f7ae4b43b7247076605b6429b7d03a1fd239c5 Reviewed-on: https://go-review.googlesource.com/c/go/+/188238 Reviewed-by: Austin Clements <austin@google.com>
2019-04-15cmd/link, runtime: mark goexit as the top of the call stackMichael Munday
This CL adds a new attribute, TOPFRAME, which can be used to mark functions that should be treated as being at the top of the call stack. The function `runtime.goexit` has been marked this way on architectures that use a link register. This will stop programs that use DWARF to unwind the call stack from unwinding past `runtime.goexit` on architectures that use a link register. For example, it eliminates "corrupt stack?" warnings when generating a backtrace that hits `runtime.goexit` in GDB on s390x. Similar code should be added for non-link-register architectures (i.e. amd64, 386). They mark the top of the call stack slightly differently to link register architectures so I haven't added that code (they need to mark "rip" as undefined). Fixes #24385. Change-Id: I15b4c69ac75b491daa0acf0d981cb80eb06488de Reviewed-on: https://go-review.googlesource.com/c/go/+/169726 Run-TryBot: Michael Munday <mike.munday@ibm.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2019-04-12cmd/internal/obj: stop plist flushing early on errorJosh Bleecher Snyder
If preprocessing or assembling has failed, we should not proceed. First, there's no point. Second, I will shortly add some sanity checks to linkpcln that will fail on malformed input. Change-Id: I055eeab1c2f3a66b4b2cadb551bbf4ab55d176f4 Reviewed-on: https://go-review.googlesource.com/c/go/+/171886 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-12-11cmd/compile: use innermost line number for -SKeith Randall
When functions are inlined, for instructions in the inlined body, does -S print the location of the call, or the location of the body? Right now, we do the former. I'd like to do the latter by default, it makes much more sense when reading disassembly. With mid-stack inlining enabled in more cases, this quandry will come up more often. The original behavior is still available with -S=2. Some tests use this mode (so they can find assembly generated by a particular source line). This helped me with understanding what the compiler was doing while fixing #29007. Change-Id: Id14a3a41e1b18901e7c5e460aa4caf6d940ed064 Reviewed-on: https://go-review.googlesource.com/c/153241 Reviewed-by: David Chase <drchase@google.com>
2018-11-03cmd/compile: avoid duplicate GC bitmap symbolsAustin Clements
Currently, liveness produces a distinct obj.LSym for each GC bitmap for each function. These are then named by content hash and only ultimately deduplicated by WriteObjFile. For various reasons (see next commit), we want to remove this deduplication behavior from WriteObjFile. Furthermore, it's inefficient to produce these duplicate symbols in the first place. GC bitmaps are the only source of duplicate symbols in the compiler. This commit eliminates these duplicate symbols by declaring them in the Ctxt symbol hash just like every other obj.LSym. As a result, all GC bitmaps with the same content now refer to the same obj.LSym. The next commit will remove deduplication from WriteObjFile. For #27539. Change-Id: I4f15e3d99530122cdf473b7a838c69ef5f79db59 Reviewed-on: https://go-review.googlesource.com/c/146557 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-08-20cmd/internal/obj: remove pointless validationXia Bin
s.Func.Text only can be nil at the moment, otherwise there has some bugs in compiler's Go rumtime. Change-Id: Ib2ff9bb977352838e67f2b98a69468f6f350c1f3 Reviewed-on: https://go-review.googlesource.com/123535 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>