Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Change-Id: I91873aaebf79bdf1c00d38aacc1a1fb8d79656a7
Reviewed-on: https://go-review.googlesource.com/21433
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
It is valid for io.Reader to return (n, io.EOF) where n is positive.
The unit test should not fail if io.EOF is returned when read until
the end.
Change-Id: I7b918e3cc03db8b90c8aa58f4c0f7806a1d4af7e
Reviewed-on: https://go-review.googlesource.com/21307
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This change removes a lot of dead code. Some of the code has never been
used, not even when it was first commited. The rest shouldn't have
survived refactors.
This change doesn't remove unused routines helpful for debugging, nor
does it remove code that's used in commented out blocks of code that are
only unused temporarily. Furthermore, unused constants weren't removed
when they were part of a set of constants from specifications.
One noteworthy omission from this CL are about 1000 lines of unused code
in cmd/fix, 700 lines of which are the typechecker, which hasn't been
used ever since the pre-Go 1 fixes have been removed. I wasn't sure if
this code should stick around for future uses of cmd/fix or be culled as
well.
Change-Id: Ib714bc7e487edc11ad23ba1c3222d1fd02e4a549
Reviewed-on: https://go-review.googlesource.com/20926
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
These new methods help find the compilation unit to pass to the
LineReader method in order to find the line information for a PC.
The Ranges method also helps identify the specific function for a PC,
needed to determine the function name.
This uses the .debug.ranges section if necessary, and changes the object
file format packages to pass in the section contents if available.
Change-Id: I5ebc3d27faaf1a126ffb17a1e6027efdf64af836
Reviewed-on: https://go-review.googlesource.com/20769
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.
Go policy has been single space after periods in comments for some time.
The copyright header template at:
https://golang.org/doc/contribute.html#copyright
also uses a single space.
Make them all consistent.
Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Named returned values should only be used on public funcs and methods
when it contributes to the documentation.
Named return values should not be used if they're only saving the
programmer a few lines of code inside the body of the function,
especially if that means there's stutter in the documentation or it
was only there so the programmer could use a naked return
statement. (Naked returns should not be used except in very small
functions)
This change is a manual audit & cleanup of public func signatures.
Signatures were not changed if:
* the func was private (wouldn't be in public godoc)
* the documentation referenced it
* the named return value was an interesting name. (i.e. it wasn't
simply stutter, repeating the name of the type)
There should be no changes in behavior. (At least: none intended)
Change-Id: I3472ef49619678fe786e5e0994bdf2d9de76d109
Reviewed-on: https://go-review.googlesource.com/20024
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
Plan 9 doesn't define main, so the INITENTRY
symbol remains with the SXREF type, which leads
Entryvalue to fail on "entry not text: main".
Fixes#14536.
Change-Id: Id9b7d61e5c2202aba3ec9cd52f5b56e0a38f7c47
Reviewed-on: https://go-review.googlesource.com/19973
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently readType simultaneously constructs a type graph and resolves
the sizes of the types. However, these two operations are
fundamentally at odds: the order we parse a cyclic structure in may be
different than the order we need to resolve type sizes in. As a
result, it's possible that when readType attempts to resolve the size
of a typedef, it may dereference a nil Type field of another typedef
retrieved from the type cache that's only partially constructed.
To fix this, we delay resolving typedef sizes until the end of the
readType recursion, when the full type graph is constructed.
Fixes#13039.
Change-Id: I9889af37fb3be5437995030fdd61e45871319d07
Reviewed-on: https://go-review.googlesource.com/18459
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This future-proofs the Chdr64 structure against later versions of ELF
defining this field and declutters the documentation without changing
the layout of the struct.
This structure does not exist in the current release, so this change
is safe.
Change-Id: I239aad7243ddaf063a1f8cd521d8a50b30413281
Reviewed-on: https://go-review.googlesource.com/18028
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This adds support for compressed ELF sections. This compression is
treated as a framing issue and hence the package APIs all
transparently decompress compressed sections. This requires some
subtlety for (*Section).Open, which returns an io.ReadSeeker: since
the decompressed data comes from an io.Reader, this commit introduces
a Reader-to-ReadSeeker adapter that is efficient for common uses of
Seek and does what it can otherwise.
Fixes#11773.
Change-Id: Ic0cb7255a85cadf4c1d15fb563d5a2e89dbd3c36
Reviewed-on: https://go-review.googlesource.com/17341
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
GCC and LLVM support zlib-compressing DWARF debug sections (and
there's some evidence that this may be happening by default in some
circumstances now).
Add support for reading compressed DWARF sections. Since ELF
relocations apply to the decompressed data, decompression is done
before applying relocations. Since relcations are applied by
debug/elf, decompression must also be handled there.
Note that this is different from compressed ELF sections, which is a
more general mechanism used by very recent versions of GCC.
Updates #11773.
Change-Id: I3f4bf1b04d0802cc1e8fcb7c2a5fcf6c467c5089
Reviewed-on: https://go-review.googlesource.com/17340
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
The self tests do not need to build the binary; they won't read it. The
self tests should work on any ELF system.
Use t.Skip instead of panic. Use internal/testenv. Don't worry about a
space in the temporary directory name.
Change-Id: I66ef0af90520d330820afa7b6c6b3a132ab27454
Reviewed-on: https://go-review.googlesource.com/15495
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This adds a test that debug/dwarf can read the skeleton DWARF data
from a split DWARF image (though it doesn't currently support piecing
the external DWARF data back together). This should work because
there's nothing particularly different about skeleton DWARF data, but
previously failed because of poor handling of unrecognized attributes.
Updates #12592.
Change-Id: I2fc5f4679883b05ebd7ec9f0b5c398a758181a32
Reviewed-on: https://go-review.googlesource.com/14542
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: jcd . <jcd@golang.org>
Currently, if the .debug_abbrev section of an ELF file contains
attributes that aren't known to the dwarf package and that have form
formSecOffset, the dwarf package will fail to open the DWARF data with
an error like "decoding dwarf section abbrev at offset 0x17: cannot
determine class of unknown attribute with formSecOffset". For the most
part, the class is implied by the form encoded in the abbrev section,
but formSecOffset can imply many different DWARF classes. Hence,
debug/dwarf disambiguates these using a table of known attributes.
However, it will reject the entire image if it encounters an attribute
it can't determine the class of. This is particularly unfortunate
because the caller may never even uses the offending attribute.
Fix this by introducing a ClassUnknown attribute class to use as a
fallback in these cases. This allows the dwarf package to load the
DWARF data and isolates the problem to just the affected attributes.
Fixes#12592.
Change-Id: I766227b136e9757f8b89c0b3ab8e9ddea899d94f
Reviewed-on: https://go-review.googlesource.com/14541
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: jcd . <jcd@golang.org>
Simplify slice/map literal expressions.
Caught with gofmt -d -s, fixed with gofmt -w -s
Reformatted some expressions to improve readability.
Change-Id: Iaf123e6bd49162ec45c59297ad3b002ca59443bc
Reviewed-on: https://go-review.googlesource.com/13850
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Section.Data returns disk section data, but those are rounded up to
some predefined value. Processing these as is confuses dwarf parser
because of garbage at the end. Truncate Section.Data as per memory
section description.
Sometimes dwarf sections have memory section size of 0
(for pe object files). Keep those to their disk size.
Fixes#11608
Change-Id: I8de0a2271201a24aa9ac8dac44f1e9c8a9285183
Reviewed-on: https://go-review.googlesource.com/11950
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The original version of applyRelocationsARM was added in
http://golang.org/cl/7266. It was added to fix the ARM build, which
had been broken by http://golang.org/cl/6780.
Before CL 6780, there was no relocation processing for ARM. CL 6780
changed the code to require relocation processing for every supported
target. CL 7266 fixed the ARM build by adding a relocation processing
function, but in fact no actual processing was done. The code only
looked for REL32 relocations, but ARM debug info has no such
relocations. The test case added in CL 7266 doesn't have any either.
This didn't matter because no relocation processing was required on
ARM, at least not for GCC-generated debug info. GCC generates ABS32
relocations, but only against section symbols which have the value 0.
Therefore, the addition done by correct handling of ABS32 doesn't
change anything.
Clang, however, generates ABS32 relocations against local symbols,
some of which have non-zero values. For those, we need to handle
ABS32 relocations.
This patch corrects the CL 7266 to look for ABS32 relocations instead
of REL32 relocations. The code was already written to correctly
handle ABS32 relocations, it just mistakenly said REL32.
This is the ARM equivalent of https://golang.org/cl/96680045, which
fixed the same problem in the same way for clang on 386.
With this patch, clang-3.5 can be used to build Go on ARM GNU/Linux.
Fixes#8980.
Change-Id: I0c2d72eadfe6373bde99cd03eee40de6a582dda1
Reviewed-on: https://go-review.googlesource.com/11222
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
These were found by grepping the comments from the go code and feeding
the output to aspell.
Change-Id: Id734d6c8d1938ec3c36bd94a4dbbad577e3ad395
Reviewed-on: https://go-review.googlesource.com/10941
Reviewed-by: Aamir Khan <syst3m.w0rm@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This CL fixes the build to use the newly created go tool compile
and go tool link in place of go tool 5g, go tool 5l, and so on.
See golang-dev thread titled "go tool compile, etc" for background.
Although it was not a primary motivation, this conversion does
reduce the wall clock time and cpu time required for make.bash
by about 10%.
Change-Id: I79cbbdb676cab029db8aeefb99a53178ff55f98d
Reviewed-on: https://go-review.googlesource.com/10288
Reviewed-by: Rob Pike <r@golang.org>
When AttrByteSize is not present for a type, we can still determine the
size in two more cases: when the type is a Typedef referring to another
type, and when the type is a pointer and we know the default address
size.
entry.go: return after setting an error if the offset is out of range.
Change-Id: I63a922ca4e4ad2fc9e9be3e5b47f59fae7d0eb5c
Reviewed-on: https://go-review.googlesource.com/9663
Reviewed-by: Austin Clements <austin@google.com>
Currently, Entry has a Val method that looks up an attribute and
returns its value. Now that Field has more fields than the attribute
and its value, it's useful to return the whole Field and let the
caller retrieve the parts it needs.
This change adds an AttrField method to Entry that does the same
lookup at Val, but returns the whole *Field rather than just the
value.
Change-Id: Ic629744c14c0e09d7528fa1026b0e1857789948c
Reviewed-on: https://go-review.googlesource.com/8503
Reviewed-by: Ian Lance Taylor <iant@golang.org>
To return DWARF attribute values, debug/dwarf maps the DWARF attribute
value classes to Go types. Unfortunately, this mapping is ambiguous in
a way that makes it impossible to correctly interpret some DWARF
attributes as of DWARF 4. For example, AttrStartScope can be either a
constant or a rangelistptr. The attribute is interpreted differently
depending on its class, but debug/dwarf maps both classes to int64, so
the caller can't distinguish them from the Go type.
AttrDataMemberLocation is similar.
To address this, this change adds a field to type Field that indicates
the exact DWARF attribute value class of that field's value. This
makes it possible to distinguish value classes that can't be
distinguished by their Go type alone.
The root of this type ambiguity was DWARF itself. For example, DWARF 2
made no distinction between constants that were just constants and
constants that were section offsets because no attribute could have
both meanings. Hence, the single int64 type was sufficient. To avoid
introducing just another layer of ambiguity, this change takes pains
to canonicalize ambiguous classes in DWARF 2 and 3 files into the
unambiguous classes of DWARF 4.
Of course, there's no guarantee that future DWARF versions won't do
the same thing again and further subdivide the DWARF 4 classes. This
change gets ahead of this somewhat by distinguishing the various *ptr
classes even though the encoding does not. If there's some other form
of split, we can handle this in a backwards-compatible way by
introducing, for example, a Class5 field and type.
Change-Id: I4ef96d1223b0fd7f96ecf44fcc0e704a36af02b4
Reviewed-on: https://go-review.googlesource.com/8502
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Skip the test when there is no .gosymtab section in the executable
rather than crashing.
Change-Id: Ieb3df07e307f50c33cdafab38f9b5d1ac0e55c04
Reviewed-on: https://go-review.googlesource.com/5110
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Currently, the only way to know the Go type of an attribute of some
DWARF attribute class was to read the dwarf package code (or
experiment). This makes it hard to go from the DWARF specification to
writing code that uses the dwarf package.
Fix this by adding a table to the documentation comment of the Field
type that gives the correspondence between DWARF attribute classes and
Go types.
Change-Id: I57c678a551fa1eb46f8207085d5a53d44985e3e7
Reviewed-on: https://go-review.googlesource.com/7280
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
The debug/dwarf and encoding/asn1 examples were added in 2009, a few
months before Go added implicit semicolons, and never updated.
The go/ast node types have always been named just "Expr", "Stmt", and
"Decl", so the comments about "ExprNode", "StmtNode", and "DeclNode"
were likely just mistaken because the interface tag methods are
"exprNode", "stmtNode", and "declNode", respectively.
Change-Id: I9d138cc3a16c1a51453da1406914d7b320bf6270
Reviewed-on: https://go-review.googlesource.com/7980
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Many headers in DWARF sections have a "unit length" that can be either
4 bytes or 12 bytes and indicates both the length of the unit and
whether the unit is in 32-bit or 64-bit format.
Currently, we implement unit length parsing in four different places.
Add a "unitLength" method to buf that parses a unit length and use it
in these four places.
Change-Id: I7950b91caaa92aa5e19aa63debc8ae46178ecc4d
Reviewed-on: https://go-review.googlesource.com/7281
Reviewed-by: Nigel Tao <nigeltao@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change adds the minimum necessary to implement applyRelocations.
For adg, this code uses the switch statement.
Change-Id: I0989daab8d0e36c2a4f6a315ced258b832744616
Reviewed-on: https://go-review.googlesource.com/7266
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This adds simple ELF test binaries generated by gcc and clang and
compares the line tables returned by the line table reader against
tables based on the output of readelf.
The binaries were generated with
# gcc --version | head -n1
gcc (Ubuntu 4.8.2-19ubuntu1) 4.8.2
# gcc -g -o line-gcc.elf line*.c
# clang --version | head -n1
Ubuntu clang version 3.4-1ubuntu3 (tags/RELEASE_34/final) (based on LLVM 3.4)
# clang -g -o line-clang.elf line*.c
Change-Id: Id210fdc1d007ac9719e8f5dc845f2b94eed12234
Reviewed-on: https://go-review.googlesource.com/7070
Reviewed-by: Nigel Tao <nigeltao@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
This implements a LineReader for line tables that parallels the
existing Reader for debug entries.
This code is partly based on the debug subrepo's fork of dwarf, but it
is a more complete (and, I believe, correct) implementation of the
spec and exposes a more general API. While the debug subrepo's
implementation exposed only a PC-to-line function, this version
exposes the line table rows to the caller. This way the caller can
make its own trade-offs when implementing PC-to-line (or line-to-PC),
such as whether or not to build an index for fast lookup.
Change-Id: Ie157bc817f55e940b6f2e1ae010c5a4e1f29c5c8
Reviewed-on: https://go-review.googlesource.com/6734
Reviewed-by: Nigel Tao <nigeltao@golang.org>
This factors out the code for finding which unit contains an offset in
the "info" section. The new code also replaces linear search with a
binary search. The line table reader will also need this
functionality.
Change-Id: I2076e4fc6719b6f06fd2796cbbc7548ec1876cb3
Reviewed-on: https://go-review.googlesource.com/6733
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Change-Id: Ia6f9bd77a3d4250339dcb054edc76942864dd358
Reviewed-on: https://go-review.googlesource.com/6781
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Previously, different DWARF sections had relocations applied in very
different ways. .debug_info was relocated, but only on x86-64 and 386
and using hard-coded relocation section names instead of relocation
links. .debug_abbrev and .debug_str were never relocated (which is
excusable because they shouldn't need it). .debug_types sections were
relocated on all architectures and found their relocation section
using a relocation link because section names could be ambiguous.
Simplify all of this so that every DWARF section that has a linked
relocation section gets those relocations applied.
This prepares this code to load .debug_line sections without the need
for yet more ad hoc relocation logic.
Change-Id: Ia00ac8e656b22f22bb31a5f6ef9b0f23cda64d19
Reviewed-on: https://go-review.googlesource.com/6780
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This CL will break any uses of 'go tool 5a' etc.
That is intentional.
Code that invokes an assembler directly should be updated to use go tool asm.
We plan to keep the old5a around for bit-for-bit verification during
the release testing phase, but we plan to remove those tools for the
actual release. Renaming the directory now makes sure that lingering
references to 'go tool 5a' will be caught, changed to use asm, and
tested during the release evaluation.
Change-Id: I98748a7ddb34cc7f1b151c2ef421d3656821f5c2
Reviewed-on: https://go-review.googlesource.com/6366
Reviewed-by: Rob Pike <r@golang.org>
