Before this patch, debugify would insert debug value intrinsics before the
terminating instruction in a block. This had the advantage of being simple,
but was a bit too simple/unrealistic.
This patch teaches debugify to insert debug values immediately after their
operand defs. This enables better testing of the compiler.
For example, with this patch, `opt -debugify-each` is able to identify a
vectorizer DI-invariance bug fixed in llvm.org/PR32761. In this bug, the
vectorizer produced different output with/without debug info present.
Reverting Davide's bugfix locally, I see:
$ ~/scripts/opt-check-dbg-invar.sh ./bin/opt \
.../SLPVectorizer/AArch64/spillcost-di.ll -slp-vectorizer
Comparing: -slp-vectorizer .../SLPVectorizer/AArch64/spillcost-di.ll
Baseline: /var/folders/j8/t4w0bp8j6x1g6fpghkcb4sjm0000gp/T/tmp.iYYeL1kf
With DI : /var/folders/j8/t4w0bp8j6x1g6fpghkcb4sjm0000gp/T/tmp.sQtQSeet
9,11c9,11
< %5 = getelementptr inbounds %0, %0* %2, i64 %0, i32 1
< %6 = bitcast i64* %4 to <2 x i64>*
< %7 = load <2 x i64>, <2 x i64>* %6, align 8, !tbaa !0
---
> %5 = load i64, i64* %4, align 8, !tbaa !0
> %6 = getelementptr inbounds %0, %0* %2, i64 %0, i32 1
> %7 = load i64, i64* %6, align 8, !tbaa !5
12a13
> store i64 %5, i64* %8, align 8, !tbaa !0
14,15c15
< %10 = bitcast i64* %8 to <2 x i64>*
< store <2 x i64> %7, <2 x i64>* %10, align 8, !tbaa !0
---
> store i64 %7, i64* %9, align 8, !tbaa !5
:: Found a test case ^
Running this over the *.ll files in tree, I found four additional examples
which compile differently with/without DI present. I plan on filing bugs for
these.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334118 91177308-0d34-0410-b5e6-96231b3b80d8
As is the case with musttail calls, the IR does not allow for
instructions inserted after a terminating deopt.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333976 91177308-0d34-0410-b5e6-96231b3b80d8
The -check-debugify pass should preserve all analyses. Otherwise, it may
invalidate an optional analysis and inadvertently alter codegen.
The test case is reduced from deopt-bundle.ll. The result of `opt -O1`
on this file would differ when -debugify-each was toggled. That happened
because CheckDebugify failed to preserve GlobalsAA.
Thanks to Davide Italiano for his help chasing this down!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333959 91177308-0d34-0410-b5e6-96231b3b80d8
After r333856, opt -debugify would just stop emitting debug value
intrinsics after encountering a musttail call. This wasn't sufficient to
avoid verifier failures.
Debug value intrinicss for all instructions preceding a musttail call
must also be emitted before the musttail call.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333866 91177308-0d34-0410-b5e6-96231b3b80d8
Placing meta-instructions into EH pads breaks certain IR invariants, as
does placing instructions after a musttail call.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333856 91177308-0d34-0410-b5e6-96231b3b80d8
Setting the "Debug Info Version" module flag makes it possible to pipe
synthetic debug info into llc, which is useful for testing backends.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333237 91177308-0d34-0410-b5e6-96231b3b80d8
Currently debugify prints it's output to stdout,
with this patch all the output generated goes to stderr.
This change lets us use debugify without taking away
the ability to pipe the output to other llvm tools.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332642 91177308-0d34-0410-b5e6-96231b3b80d8
This adds a -debugify-each mode to opt which, when enabled, wraps each
{Module,Function}Pass in a pipeline with logic to add, check, and strip
synthetic debug info for testing purposes.
This mode can be used to test complex pipelines for debug info bugs, or
to collect statistics about the number of debug values & locations lost
throughout various stages of a pipeline.
Patch by Son Tuan Vu!
Differential Revision: https://reviews.llvm.org/D46525
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332312 91177308-0d34-0410-b5e6-96231b3b80d8
If no debug info was applied to a function, its debug info shouldn't be
checked (it doesn't have any :).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325297 91177308-0d34-0410-b5e6-96231b3b80d8
If a function doesn't have an exact definition, don't apply debugify
metadata as it triggers a DIVerifier failure.
The issue is that it's invalid to have DILocations inside a DISubprogram
which isn't a definition ("scope points into the type hierarchy!").
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325036 91177308-0d34-0410-b5e6-96231b3b80d8
Opt's "-enable-debugify" mode adds an instance of Debugify at the
beginning of the pass pipeline, and an instance of CheckDebugify at the
end.
You can enable this mode with lit using: -Dopt="opt -enable-debugify".
Note that running test suites in this mode will result in many failures
due to strict FileCheck commands, etc.
It can be more useful to look for assertion failures which arise only
when Debugify is enabled, e.g to prove that we have (or do not have)
test coverage for some code path with debug info present.
Differential Revision: https://reviews.llvm.org/D41793
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323256 91177308-0d34-0410-b5e6-96231b3b80d8
The Debugify pass synthesizes debug info for IR. It's paired with a
CheckDebugify pass which determines how much of the original debug info
is preserved. These passes make it easier to create targeted tests for
debug info preservation.
Here is the Debugify algorithm:
NextLine = 1
for (Instruction &I : M)
attach DebugLoc(NextLine++) to I
NextVar = 1
for (Instruction &I : M)
if (canAttachDebugValue(I))
attach dbg.value(NextVar++) to I
The CheckDebugify pass expects contiguous ranges of DILocations and
DILocalVariables. If it fails to find all of the expected debug info, it
prints a specific error to stderr which can be FileChecked.
This was discussed on llvm-dev in the thread:
"Passes to add/validate synthetic debug info"
Differential Revision: https://reviews.llvm.org/D40512
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320202 91177308-0d34-0410-b5e6-96231b3b80d8
