Currently debug/dwarf assumes all paths in line tables will be
UNIX-style paths, which obviously isn't the case for binaries built on
Windows. However, we can't simply switch from the path package to the
filepath package because we don't know that we're running on the same
host type that built the binary and we want this to work even if we're
not. This is essentially the approach taken by GDB, which treats paths
in accordance with the system GDB itself is compiled for. In fact, we
can't even guess the compilation system from the type of the binary
because it may have been cross-compiled.
We fix this by heuristically determining whether paths are UNIX-style
or DOS-style by looking for a drive letter or UNC path. If we see a
DOS-style path, we use appropriate logic for determining whether the
path is absolute and for joining two paths. This is helped by the fact
that we should basically always be starting with an absolute path.
However, it could mistake a relative UNIX-style path that begins with
a directory like "C:" for an absolute DOS-style path. There doesn't
seem to be any way around this.
Fixes#19784.
Change-Id: Ie13b546d2f1dcd8b02e668583a627b571b281588
Reviewed-on: https://go-review.googlesource.com/44017
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
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>
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 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>
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>
Austin Clements