The original meaning of type Func was "extra fields factored out
of a few cases of type Node having to do with functions",
but those specific cases didn't necessarily have any relation.
A typical declared function is represented by an ODCLFUNC Node
at its declaration and an ONAME node at its uses, and both those
have a .Func field, but they are *different* Funcs.
Similarly, a closure is represented both by an OCLOSURE Node for
the value itself and an ODCLFUNC Node for the underlying function
implementing the closure. Those too have *different* Funcs,
and the Func.Closure field in one points to the other and vice versa.
This has led to no end of confusion over the years.
This CL elevates type Func to be the canonical identifier for
a given Go function.
This looks like a trivial CL but in fact is the result of a lot of
scaffolding and rewriting, discarded once the result was achieved, to
separate out the three different kinds of Func nodes into three
separate fields, limited in use to each specific Node type, to
understand which Func fields are used by which Node types and what the
possible overlaps are. There were a few overlaps, most notably around
closures, which led to more fields being added to type Func to keep
them separate even though there is now a single Func instead of two
different ones for each function.
A future CL can and should change Curfn to be a *Func instead of
a *Node, finally eliminating the confusion about whether Curfn
is an ODCLFUNC node (as it is most of the time) or an ONAME node
(as it is when type-checking an inlined function body).
Although sizeof_test.go makes it look like Func is growing by two
words, there are now half as many Funcs in a running compilation,
so the memory footprint has actually been reduced substantially.
Change-Id: I598bd96c95728093dc769a835d48f2154a406a61
Reviewed-on: https://go-review.googlesource.com/c/go/+/272253
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
We want to introduce a package cmd/compile/internal/base,
and these will shadow it at points where it is needed.
Change-Id: Ic936733fba1ccba8c2ca1fdedbd4d2989df4bbf4
Reviewed-on: https://go-review.googlesource.com/c/go/+/272249
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Prepare for factoring the error API out of this package by
cleaning it up. The doc comments use the intended new names,
which will be introduced in the next CL.
Change-Id: Ie4c8d4262422da32a9a9f750fda42c225b6b42a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/272248
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
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>
The linker prunes methods that are not directly reachable if the
receiver type is never converted to interface. Currently, this
"never" is too strong: it is invalidated even if the interface
conversion is in an unreachable function. This CL improves it by
only considering interface conversions in reachable code. To do
that, we introduce a marker relocation R_USEIFACE, which marks
the target symbol as UsedInIface if the source symbol is reached.
binary size before after
cmd/compile 18897528 18887400
cmd/go 13607372 13470652
Change-Id: I66c6b69eeff9ae02d84d2e6f2bc7f1b29dd53910
Reviewed-on: https://go-review.googlesource.com/c/go/+/256797
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
I think they are no longer experimental status. Might as well promote
them to permanent.
Change-Id: Id1259601b3dd2061dd60df86ee48080bfb575d2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/249857
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
More ergonomic that way. Also change Haspointers to HasPointers
while we are here.
Change-Id: I45bedc294c1a8c2bd01dc14bd04615ae77555375
Reviewed-on: https://go-review.googlesource.com/c/go/+/249959
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Background: when compiling a function, it's possible that a local
variable will be optimized away, which could potentially degrade the
debugging experience if the compiler fails to emit DWARF information
for the variable's type. To mitigate this situation, the compiler
emits R_USETYPE relocations for the function's auto/param variables as
a signal to the linker to generate DWARF for the types in question,
even if the type is not specifically attached to a DWARF param or var.
This patch change the logic in the compiler to avoid emitting a
R_USETYPE relocation if the type in question is already referenced by
a concrete DWARF param or auto record. This cuts down on the amount of
work the linker has to do, also makes object files a bit smaller on
average (about 1% for the runtime package).
Change-Id: I4d24da458d0658edf90c5dca0bf21d5ddc3961d8
Reviewed-on: https://go-review.googlesource.com/c/go/+/234837
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
When the concurrent back end is not enabled, it is possible to have a
scenario where: we compile a specific inlinable non-pointer-receiver
method T.M, then at some point later on in the compilation we visit a
type that triggers generation of a pointer-receiver wrapper (*T).M,
which then results in an inline of T.M into (*T).M. This introduces
subtle differences in the DWARF as compared with when the concurrent
back end is enabled (in the concurrent case, by the time we run the
SSA back end on T.M is is marked as being inlined, whereas in the
non-current case it is not marked inlined).
As a fix, at the point where we would normally compile a given
function in the xtop list right away, if the function is a method AND
is inlinable AND hasn't been inlined, then delay its compilation until
compileFunctions (so as to make sure that when we do compile it, all
possible inlining has been complete). In addition, make sure that
the abstract function symbol for the inlined function gets recorded
correctly.
Fixes#38068.
Change-Id: I57410ab5658bd4ee5b4b80750518e9b20fd6ba52
Reviewed-on: https://go-review.googlesource.com/c/go/+/234178
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
In golang.org/cl/171464, we cleaned up generation of .stkobj linker
symbols, but we couldn't figure out why a similar cleanup to
.args_stackmap linker symbols caused problems.
The issue is that we only need/want to generate .args_stackmap for
functions that are implemented in assembly in the same package. When
"pulling" a function from another package via //go:linkname, we can
safely skip emitting .args_stackmap, because compiling that package
will have generated it, if necessary.
Fixes#31615.
Change-Id: If8680aa7dd5b4e8f268b6b032d746f1b8536c867
Reviewed-on: https://go-review.googlesource.com/c/go/+/223238
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Fixes the declaration line reported in the DW_AT_decl_line for
variables captured in a closure.
Fixes#36542
Change-Id: I228d32b57121fd62c4615c2ef71a6e8da616a1e2
Reviewed-on: https://go-review.googlesource.com/c/go/+/214637
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
The IsClosureVar, IsOutputParamHeapAddr, Assigned, Addrtaken,
InlFormal, and InlLocal flags are only interesting for ONAME nodes, so
it's better to set these flags on Name.flags instead of Node.flags.
Two caveats though:
1. Previously, we would set Assigned and Addrtaken on the entire
expression tree involved in an assignment or addressing operation.
However, the rest of the compiler only actually cares about knowing
whether the underlying ONAME (if any) was assigned/addressed.
2. This actually requires bumping Name.flags from bitset8 to bitset16,
whereas it doesn't allow shrinking Node.flags any. However, Name has
some trailing padding bytes, so expanding Name.flags doesn't cost any
memory.
Passes toolstash-check.
Change-Id: I7775d713566a38d5b9723360b1659b79391744c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/200898
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Don't write Autom records when writing a function to the object file;
we no longer need them in the linker for DWARF processing. So as to
keep the object file format unchanged, write out a zero-length list of
automs to the object, as opposed to removing all references.
Updates #34554.
Change-Id: I42a1d67207ea7114ae4f3a315cf37effba57f190
Reviewed-on: https://go-review.googlesource.com/c/go/+/197499
Reviewed-by: Jeremy Faller <jeremy@golang.org>
During DWARF processing, keep track of the go type symbols for types
directly or indirectly referenced by auto variables in a function,
and add a set of dummy R_USETYPE relocations to the function's DWARF
subprogram DIE symbol.
This change is not useful on its own, but is part of a series of
changes intended to clean up handling of autom's in the compiler
and linker.
Updates #34554.
Change-Id: I974afa9b7092aa5dba808f74e00aa931249d6fe9
Reviewed-on: https://go-review.googlesource.com/c/go/+/197497
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
CL 14870 added internal/race to factor out duplicated race thunks,
we should use it.
No signification changes in compile time and compile binary size.
Change-Id: I786af44dd5bb0f4ab6709432eeb603f27a5b6c63
Reviewed-on: https://go-review.googlesource.com/c/go/+/178118
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
We compile package sort as part of the compiler bootstrap,
to make sure the compiler uses a consistent sort algorithm
no matter what version of Go it is compiled against.
(This matters for elements that compare "equal" but are distinguishable.)
Package sort was compiled in such a way as to disallow
sort.Slice entirely during bootstrap (at least with some compilers),
while cmd/internal/obj was compiled in such a way as to
make obj.SortSlice available to all compilers, precisely because
sort.Slice was not. This is all highly confusing.
Simplify by making sort.Slice available all the time.
Followup to CL 169137 and #30440
(and also CL 40114 and CL 73951).
Change-Id: I127f4e02d6c71392805d256c3a90ef7c51f9ba0c
Reviewed-on: https://go-review.googlesource.com/c/go/+/174525
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Stack object generation code was always using the local package name
for its symbol. Normally that doesn't matter, as we usually only
compile functions in the local package. But for wrappers, the compiler
generates functions which live in other packages. When there are two
other packages with identical functions to wrap, the same name appears
twice, and the compiler goes boom.
Fixes#31252
Change-Id: I7026eebabe562cb159b8b6046cf656afd336ba25
Reviewed-on: https://go-review.googlesource.com/c/go/+/171464
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
When generating DWARF inline info records, the post-SSA code looks
through the original "pre-inline" dcl list for the function so as to
handle situations where formal params are promoted or optimized away.
This code was not properly handling the case where an output parameter
was promoted to the heap -- in this case the param node is converted
in place from class PPARAMOUT to class PAUTOHEAP. This caused
inconsistencies later on, since the variable entry in the abstract
subprogram DIE wound up as a local and not an output parameter.
Fixes#30908.
Change-Id: Ia70b89f0cf7f9b16246d95df17ad6e307228b8c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/168818
Reviewed-by: Cherry Zhang <cherryyz@google.com>
If a for loop has a simple condition and begins with a simple
"if x { break; }"; we can simply add "!x" to the loop's condition.
While at it, simplify a few assignments to use the common pattern
"x := staticDefault; if cond { x = otherValue(); }".
Finally, simplify a couple of var declarations.
Change-Id: I413982c6abd32905adc85a9a666cb3819139c19f
Reviewed-on: https://go-review.googlesource.com/c/go/+/165342
Run-TryBot: Daniel Martà <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
They can't be used, so we don't need code generated for them. We just
need to report errors in their bodies.
The compiler currently has a bunch of special cases sprinkled about
for "_" functions, because we never generate a linker symbol for them.
Instead, abort compilation earlier so we never reach any of that
special-case code.
Fixes#29870
Change-Id: I3530c9c353deabcf75ce9072c0b740e992349ee5
Reviewed-on: https://go-review.googlesource.com/c/158845
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
They can't be used, so we don't need code generated for them. We just
need to report errors in their bodies.
This is the minimal CL for 1.12. For 1.13, CL 158845 will remove
a bunch of special cases sprinkled about the compiler to handle "_"
functions, which should (after this CL) be unnecessary.
Update #29870
Change-Id: Iaa1c194bd0017dffdce86589fe2d36726ee83c13
Reviewed-on: https://go-review.googlesource.com/c/158820
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
If someone takes a pointer to a zero-sized stack variable, it can
be incorrectly interpreted as a pointer to the next object in the
stack frame. To avoid this, add some padding after zero-sized variables.
We only need to pad if the next variable in memory (which is the
previous variable in the order in which we allocate variables to the
stack frame) has pointers. If the next variable has no pointers, it
won't hurt to have a pointer to it.
Because we allocate all pointer-containing variables before all
non-pointer-containing variables, we should only have to pad once per
frame.
Fixes#24993
Change-Id: Ife561cdfdf964fdbf69af03ae6ba97d004e6193c
Reviewed-on: https://go-review.googlesource.com/c/155698
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This case was missed entirely and caused such params to be
unprintable. This change gives them stack addresses
for the entire function (which is correct).
Change-Id: Ia4f706450219e48bce65b6395d3d9792df142fb5
Reviewed-on: https://go-review.googlesource.com/c/150657
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
This implements compiler and linker support for separating the
function calling ABI into two ABIs: a stable and an internal ABI. At
the moment, the two ABIs are identical, but we'll be able to evolve
the internal ABI without breaking existing assembly code that depends
on the stable ABI for calling to and from Go.
The Go compiler generates internal ABI symbols for all Go functions.
It uses the symabis information produced by the assembler to create
ABI wrappers whenever it encounters a body-less Go function that's
defined in assembly or a Go function that's referenced from assembly.
Since the two ABIs are currently identical, for the moment this is
implemented using "ABI alias" symbols, which are just forwarding
references to the native ABI symbol for a function. This way there's
no actual code involved in the ABI wrapper, which is good because
we're not deriving any benefit from it right now. Once the ABIs
diverge, we can eliminate ABI aliases.
The linker represents these different ABIs internally as different
versions of the same symbol. This way, the linker keeps us honest,
since every symbol definition and reference also specifies its
version. The linker is responsible for resolving ABI aliases.
Fixes#27539.
Change-Id: I197c52ec9f8fc435db8f7a4259029b20f6d65e95
Reviewed-on: https://go-review.googlesource.com/c/147160
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Rework how the compiler+runtime handles stack-allocated variables
whose address is taken.
Direct references to such variables work as before. References through
pointers, however, use a new mechanism. The new mechanism is more
precise than the old "ambiguously live" mechanism. It computes liveness
at runtime based on the actual references among objects on the stack.
Each function records all of its address-taken objects in a FUNCDATA.
These are called "stack objects". The runtime then uses that
information while scanning a stack to find all of the stack objects on
a stack. It then does a mark phase on the stack objects, using all the
pointers found on the stack (and ancillary structures, like defer
records) as the root set. Only stack objects which are found to be
live during this mark phase will be scanned and thus retain any heap
objects they point to.
A subsequent CL will remove all the "ambiguously live" logic from
the compiler, so that the stack object tracing will be required.
For this CL, the stack tracing is all redundant with the current
ambiguously live logic.
Update #22350
Change-Id: Ide19f1f71a5b6ec8c4d54f8f66f0e9a98344772f
Reviewed-on: https://go-review.googlesource.com/c/134155
Reviewed-by: Austin Clements <austin@google.com>
When generation DWARF inline info records, the current implementation
includes a sorting pass that reorders a subprogram's child variable
DIEs based on class (param/auto) and name. This sorting is no longer
needed, and can cause problems for a debugger (if we want to use the
DWARF info for creating a call to an optimized function); this patch
removes it.
Ordering of DWARF subprogram variable/parameter DIEs is still
deterministic with this change, since it is keyed off the order in
which vars appear in the pre-inlining function "Dcl" list.
Updates #27039
Change-Id: I3b91290d11bb3b9b36fb61271d80b801841401ee
Reviewed-on: https://go-review.googlesource.com/131895
Reviewed-by: Heschi Kreinick <heschi@google.com>
The stack frame includes the callee args section. At the point where
we were checking the frame size, that part of the frame had not been
computed yet. Move the check later so we can include the callee args size.
Fixes#20780
Update #25507
Change-Id: Iab97cb89b3a24f8ca19b9123ef2a111d6850c3fe
Reviewed-on: https://go-review.googlesource.com/115195
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Extend stack frame limit of 1GB to include large argument/return areas.
Argument/return areas are part of the parent frame, not the frame itself,
so they need to be handled separately.
Fixes#25507.
Change-Id: I309298a58faee3e7c1dac80bd2f1166c82460087
Reviewed-on: https://go-review.googlesource.com/115036
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Inl, Inldcl, and InlCost are only applicable to functions with bodies
that can be inlined, so pull them out into a separate Inline type to
make understanding them easier.
A side benefit is that we can check if a function can be inlined by
just checking if n.Func.Inl is non-nil, which simplifies handling of
empty function bodies.
While here, remove some unnecessary Curfn twiddling, and make imported
functions use Inl.Dcl instead of Func.Dcl for consistency for local
functions.
Passes toolstash-check.
Change-Id: Ifd4a80349d85d9e8e4484952b38ec4a63182e81f
Reviewed-on: https://go-review.googlesource.com/104756
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
To improve debugging, instructions should be annotated with
DWARF is_stmt. The DWARF default before was is_stmt=1, and
to remove "jumpy" stepping the optimizer was tagging
instructions with a no-position position, which interferes
with the accuracy of profiling information. This allows
that to be corrected, and also allows more "jumpy" positions
to be annotated with is_stmt=0 (these changes were not made
for 1.10 because of worries about further messing up
profiling).
The is_stmt values are placed in a pc-encoded table and
passed through a symbol derived from the name of the
function and processed in the linker alongside its
processing of each function's pc/line tables.
The only change in binary size is in the .debug_line tables
measured with "objdump -h --section=.debug_line go1.test"
For go1.test, these are 2614 bytes larger,
or 0.72% of the size of .debug_line,
or 0.025% of the file size.
This will increase in proportion to how much the is_stmt
flag is used (toggled).
Change-Id: Ic1f1aeccff44591ad0494d29e1a0202a3c506a7a
Reviewed-on: https://go-review.googlesource.com/93664
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Remove a couple of unnecessary var declarations, an unused sort.Sort
type, and simplify a range by using the two-name variant.
Change-Id: Ia251f634db0bfbe8b1d553b8659272ddbd13b2c3
Reviewed-on: https://go-review.googlesource.com/102336
Run-TryBot: Daniel Martà <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
As reported by unparam.
Passes toolstash -cmp on std cmd.
Change-Id: I55473e1eed096ed1c3e431aed2cbf0b6b5444b91
Reviewed-on: https://go-review.googlesource.com/97895
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Instead of creating a new &nodfp expression for every recover() call,
or a new nodpc variable for every function instrumented by the race
detector, this CL introduces two new uintptr-typed pseudo-variables
callerSP and callerPC. These pseudo-variables act just like calls to
the runtime's getcallersp() and getcallerpc() functions.
For consistency, change runtime.gorecover's builtin stub's parameter
type from "*int32" to "uintptr".
Passes toolstash-check, but toolstash-check -race fails because of
register allocator changes.
Change-Id: I985d644653de2dac8b7b03a28829ad04dfd4f358
Reviewed-on: https://go-review.googlesource.com/99416
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martà <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
There were only two large classes of use for these variables:
1) Testing "funcdepth != 0" or "funcdepth > 0", which is equivalent to
checking "Curfn != nil".
2) In oldname, detecting whether a closure variable has been created
for the current function, which can be handled by instead testing
"n.Name.Curfn != Curfn".
Lastly, merge funcstart into funchdr, since it's only called once, and
it better matches up with funcbody now.
Passes toolstash-check.
Change-Id: I8fe159a9d37ef7debc4cd310354cea22a8b23394
Reviewed-on: https://go-review.googlesource.com/99076
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Bring these functions next to each other, and clean them up a little
bit. Also, change emitptrargsmap to take Curfn as a parameter instead
of a global.
Passes toolstash-check.
Change-Id: Ib9c94fda3b2cb6f0dcec1585622b33b4f311b5e9
Reviewed-on: https://go-review.googlesource.com/99075
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reuse even more memory, and keep track of it in a long-lived debugState
object rather than piecemeal in the Cache.
Change-Id: Ib6936b4e8594dc6dda1f59ece753c00fd1c136ba
Reviewed-on: https://go-review.googlesource.com/92404
Reviewed-by: David Chase <drchase@google.com>
During DWARF debug generation, the DW_AT_decl_line / DW_AT_decl_file
attributes for variable DIEs were being computed without taking into
account the possibility of "//line" directives. Fix things up to use
the correct src.Pos methods to pick up this info.
Fixes#23704.
Change-Id: I88c21a0e0a9602392be229252d856a6d665868e2
Reviewed-on: https://go-review.googlesource.com/92255
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Because getStackOffset is a function pointer, the compiler assumes that
its arguments escape. Pass a value instead to avoid heap allocations.
Change-Id: Ib94e5941847f134cd00e873040a4d7fcf15ced26
Reviewed-on: https://go-review.googlesource.com/92397
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Completely redesign and reimplement location list generation to be more
efficient, and hopefully not too hard to understand.
RegKills are gone. Instead of using the regalloc's liveness
calculations, redo them using the Ops' clobber information. Besides
saving a lot of Values, this avoids adding RegKills to blocks that would
be empty otherwise, which was messing up optimizations. This does mean
that it's much harder to tell whether the generation process is buggy
(there's nothing to cross-check it with), and there may be disagreements
with GC liveness. But the performance gain is significant, and it's nice
not to be messing with earlier compiler phases.
The intermediate representations are gone. Instead of producing
ssa.BlockDebugs, then dwarf.LocationLists, and then finally real
location lists, go directly from the SSA to a (mostly) real location
list. Because the SSA analysis happens before assembly, it stores
encoded block/value IDs where PCs would normally go. It would be easier
to do the SSA analysis after assembly, but I didn't want to retain the
SSA just for that.
Generation proceeds in two phases: first, it traverses the function in
CFG order, storing the state of the block at the beginning and end. End
states are used to produce the start states of the successor blocks. In
the second phase, it traverses in program text order and produces the
location lists. The processing in the second phase is redundant, but
much cheaper than storing the intermediate representation. It might be
possible to combine the two phases somewhat to take advantage of cases
where the CFG matches the block layout, but I haven't tried.
Location lists are finalized by adding a base address selection entry,
translating each encoded block/value ID to a real PC, and adding the
terminating zero entry. This probably won't work on OSX, where dsymutil
will choke on the base address selection. I tried emitting CU-relative
relocations for each address, and it was *very* bad for performance --
it uses more memory storing all the relocations than it does for the
actual location list bytes. I think I'm going to end up synthesizing the
relocations in the linker only on OSX, but TBD.
TestNexting needs updating: with more optimizations working, the
debugger doesn't stop on the continue (line 88) any more, and the test's
duplicate suppression kicks in. Also, dx and dy live a little longer
now, but they have the correct values.
Change-Id: Ie772dfe23a4e389ca573624fac4d05401ae32307
Reviewed-on: https://go-review.googlesource.com/89356
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
The helper routine for returning pre-inlining parameter declarations
wasn't properly handling the case where you have more than one
parameter named "_" in a function signature; this triggered a map
collision later on when the function was inlined and DWARF was
generated for the inlined routine instance.
Fixes#23179.
Change-Id: I12e5d6556ec5ce08e982a6b53666a4dcc1d22201
Reviewed-on: https://go-review.googlesource.com/84755
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Change the compiler's DWARF inline info generation to be more careful
about producing consistent instances of abstract function DIEs. The
new strategy is to insure that the only params/variables created in an
abstract subprogram DIE are those corresponding to declarations in the
original pre-inlining version of the code. If a concrete subprogram
winds up with other vars as part of the compilation process (return
temps, for example, or scalars generated by splitting a structure into
pieces) these are emitted as regular param/variable DIEs instead of
concrete DIEs.
The linker dwarf test now has a couple of new testpoints that include
checks to make sure that all abstract DIE references are
sane/resolvable; this will help catch similar problems in the future.
Fixes#23046.
Change-Id: I9b0030da8673fbb80b7ad50461fcf8c6ac823a37
Reviewed-on: https://go-review.googlesource.com/83675
Run-TryBot: Than McIntosh <thanm@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The DWARF inline info generation hooks weren't properly
handling unused auto vars in certain cases, triggering an assert (now
fixed). Also with this change, introduce a new autom "flavor" to
use for autom entries that are added to insure that a specific
auto type makes it into the linker (this is a follow-on to the fix
for 22941).
Fixes#22962.
Change-Id: I7a2d8caf47f6ca897b12acb6a6de0eb25f5cac8f
Reviewed-on: https://go-review.googlesource.com/81557
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The code that generates the list of DWARF variables for a function
(params and autos) will emit a "no-location" entry in the DWARF for a
user var that appears in the original pre-optimization version of the
function but is no longer around when optimization is complete. The
intent is that if a GDB user types "print foo" (where foo has been
optimized out), the response will be "<optimized out>" as opposed to
"there is no such variable 'foo'). This change fixes said code to
include vars on the autom list for the function, to insure that the
type symbol for the variable makes it to the linker.
Fixes#22941.
Change-Id: Id29f1f39d68fbb798602dfd6728603040624fc41
Reviewed-on: https://go-review.googlesource.com/81415
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Compiler and linker changes to support DWARF inlined instances,
see https://go.googlesource.com/proposal/+/HEAD/design/22080-dwarf-inlining.md
for design details.
This functionality is gated via the cmd/compile option -gendwarfinl=N,
where N={0,1,2}, where a value of 0 disables dwarf inline generation,
a value of 1 turns on dwarf generation without tracking of formal/local
vars from inlined routines, and a value of 2 enables inlines with
variable tracking.
Updates #22080
Change-Id: I69309b3b815d9fed04aebddc0b8d33d0dbbfad6e
Reviewed-on: https://go-review.googlesource.com/75550
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Fix a bug introduced in patch 2 of
https://go-review.googlesource.com/72630 (sense of a map
lookup test was accidentally flipped).
Change-Id: Icc6096ee50be4605fa7542b9fd855c13b8aff090
Reviewed-on: https://go-review.googlesource.com/72850
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
