The ssa backend is aggressive about placing constants and
certain other values in the Entry block. It's implausible
that the original line numbers for these constants makes
any sort of sense when it appears to a user stepping in a
debugger, and they're also not that useful in dumps since
entry-block instructions tend to be constants (i.e.,
unlikely to be the cause of a crash).
Therefore, use src.NoXPos for any values that are explicitly
inserted into a function's entry block.
Passes all tests, including ssa/debug_test.go with both
gdb and a fairly recent dlv. Hand-verified that it solves
the reported problem; constructed a test that reproduced
a problem, and fixed it.
Modified test harness to allow injection of slightly more
interesting inputs.
Fixes#22558.
Change-Id: I4476927067846bc4366da7793d2375c111694c55
Reviewed-on: https://go-review.googlesource.com/81215
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The locations chosen for racewalking inserted code can
be wrong and thus cause unwanted next/step behavior in
debuggers. Forcing the positions to be unset results in
better behavior.
Test added, and test harness corrected to deal with
changes to gdb's output caused by -racewalk.
Incidental changes in Delve (not part of the usual testing,
but provided because we care about Delve) also reflected
in this CL.
Fixes#22600.
Change-Id: Idd0218afed52ab8c68efd9eabbdff3c92ea2b996
Reviewed-on: https://go-review.googlesource.com/78336
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
It has always been problematic that there was no way to specify
tool flags that applied only to the build of certain packages;
it was only to specify flags for all packages being built.
The usual workaround was to install all dependencies of something,
then build just that one thing with different flags. Since the
dependencies appeared to be up-to-date, they were not rebuilt
with the different flags. The new content-based staleness
(up-to-date) checks see through this trick, because they detect
changes in flags. This forces us to address the underlying problem
of providing a way to specify per-package flags.
The solution is to allow -gcflags=pattern=flags, which means
that flags apply to packages matching pattern, in addition to the
usual -gcflags=flags, which is now redefined to apply only to
the packages named on the command line.
See #22527 for discussion and rationale.
Fixes#22527.
Change-Id: I6716bed69edc324767f707b5bbf3aaa90e8e7302
Reviewed-on: https://go-review.googlesource.com/76551
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
A statement like
foo = bar + qux
might compile to
AX := AX + BX
resulting in a regkill for AX before this instruction.
The buggy behavior is to kill AX "at" this instruction,
before it has executed. (Code generation of no-instruction
values like RegKills applies their effects at the
next actual instruction emitted).
However, bar is still associated with AX until after the
instruction executes, so the effect of the regkill must
occur at the boundary between this instruction and the
next. Similarly, the new value bound to AX is not visible
until this instruction executes (and in the case of values
that require multiple instructions in code generation, until
all of them have executed).
The ranges are adjusted so that a value's start occurs
at the next following instruction after its evaluation,
and the end occurs after (execution of) the first
instruction following the end of the lifetime as a value.
(Notice the asymmetry; the entire value must be finished
before it is visible, but execution of a single instruction
invalidates. However, the value *is* visible before that
next instruction executes).
The test was adjusted to make it insensitive to the result
numbering for variables printed by gdb, since that is not
relevant to the test and makes the differences introduced
by small changes larger than necessary/useful.
The test was also improved to present variable probes
more intuitively, and also to allow explicit indication
of "this variable was optimized out"
Change-Id: I39453eead8399e6bb05ebd957289b112d1100c0e
Reviewed-on: https://go-review.googlesource.com/74090
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
For structs, slices, strings, interfaces, etc, propagation of
names to their components (e.g., complex.real, complex.imag)
is fragile (depends on phase ordering) and not done right
for the "dec" pass.
The dec pass is subsumed into decomposeBuiltin,
and then names are pushed into the args of all
OpFooMake opcodes.
compile/ssa/debug_test.go was fixed to pay attention to
variable values, and the reference files include checks
for the fixes in this CL (which make debugging better).
Change-Id: Ic2591ebb1698d78d07292b92c53667e6c37fa0cd
Reviewed-on: https://go-review.googlesource.com/73210
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Recurse into structs/arrays of one element when
assigning names.
Test incorporated into existing end-to-end debugger test,
hand-verified that it fails without this CL.
Fixes#19868
Revives CL 40010
Old-Change-Id: I0266e58af975fb64cfa17922be383b70f0a7ea96
Change-Id: I122ac2375931477769ec8d763607c1ec42d78a7f
Reviewed-on: https://go-review.googlesource.com/71731
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Excluded when -short because it still runs relatively long,
but deflaked.
Removed timeouts from normal path and ensured that they were
not needed and that reference files did not change.
Use "tbreak" instead of "break" with gdb to reduce chance
of multiple hits on main.main. (Seems not enough, but a
move in the right direction).
By default, testing ignores repeated lines that occur when
nexting. This appears to sometimes be timing-dependent and
is the observed source of flakiness in testing so far.
Note that these can also be signs of a bug in the generated
debugging output, but it is one of the less-confusing bugs
that can occur.
By default, testing with gdb uses compilation with
inlining disabled to prevent dependence on library code
(it's a bug that library code is seen while Nexting, but
the bug is current behavior).
Also by default exclude all source files outside /testdata
to prevent accidental dependence on library code. Note that
this is currently only applicable to dlv because (for the
debugging information we produce) gdb does not indicate a
change in the source file for inlined code.
Added flags -i and -r to make gdb testing compile with
inlining and be sensitive to repeats in the next stream.
This is for developer-testing and so we can describe these
problems in bug reports.
Updates #22206.
Change-Id: I9a30ebbc65aa0153fe77b1858cf19743bdc985e4
Reviewed-on: https://go-review.googlesource.com/69930
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This makes it more obvious which of the two builds is failing by
putting "dbg" or "opt" directly in the test name. It also makes it
possible for them to fail independently, so a failure in "dbg" doesn't
mask a failure in "opt", and to visibly skip the opt test when run
with an unoptimized runtime.
Change-Id: I3403a7fd3c1a13ad51a938bb95dfe54c320bb58e
Reviewed-on: https://go-review.googlesource.com/69970
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
CL50610 broke the build for noopt (different inlining
behavior) and clang (no gdb) so it needs to catch those
cases and skip.
The run/no-run logic was slightly cleaned up,
the name of gdb on OSX was made more robust (tries gdb
first, then ggdb), and the file names were canonicalized
before loggging instead of in comparison to reduce
gratuitous noise in diffs when things aren't otherwise
equal.
This probably doesn't fix problems on Alpine, but it should
provide a cleaner and less confusing failure.
Change-Id: I26c65bff5a8d3d60f1cd6ae02a282558c53dda67
Reviewed-on: https://go-review.googlesource.com/69371
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
This attempts to choose better values for values that are
rematerialized (uses the XPos of the consumer, not the
original) and for unconditional branches (uses the last
assigned XPos in the block).
The JMP branches seem to sometimes end up with a PC in the
destination block, I think because of register movement
or rematerialization that gets placed in predecessor blocks.
This may be acceptable because (eyeball-empirically) that is
often the line number of the target block, so the line number
flow is correct.
Added proper test, that checks both -N -l and regular compilation.
The test is also capable (for gdb, delve soon) of tracking
variable printing based on comments in the source code.
There's substantial room for improvement in debugger behavior.
Updates #21098.
Change-Id: I13abd48a39141583b85576a015f561065819afd0
Reviewed-on: https://go-review.googlesource.com/50610
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
