Making -g[no-]column-info opt out reduces the length of a typical CC1 command line.
Additionally, in a non-debug compile, we won't see -dwarf-column-info.
can be used to improve the locations when generating remarks for loops.
Depends on the companion LLVM change r286227.
Patch by Florian Hahn.
Differential Revision: https://reviews.llvm.org/D25764
llvm-svn: 286456
Getting accurate locations for loops is important, because those locations are
used by the frontend to generate optimization remarks. Currently, optimization
remarks for loops often appear on the wrong line, often the first line of the
loop body instead of the loop itself. This is confusing because that line might
itself be another loop, or might be somewhere else completely if the body was
an inlined function call. This happens because of the way we find the loop's
starting location. First, we look for a preheader, and if we find one, and its
terminator has a debug location, then we use that. Otherwise, we look for a
location on an instruction in the loop header.
The fallback heuristic is not bad, but will almost always find the beginning of
the body, and not the loop statement itself. The preheader location search
often fails because there's often not a preheader, and even when there is a
preheader, depending on how it was formed, it sometimes carries the location of
some preceeding code.
I don't see any good theoretical way to fix this problem. On the other hand,
this seems like a straightforward solution: Put the debug location in the
loop's llvm.loop metadata. When emitting debug information, this commit causes
us to add the debug location as an operand to each loop's llvm.loop metadata.
Thus, we now generate this metadata for all loops (not just loops with
optimization hints) when we're otherwise generating debug information.
The remark test case changes depend on the companion LLVM commit r270771.
llvm-svn: 270772
With this change, most 'g' options are rejected by CompilerInvocation.
They remain only as Driver options. The new way to request debug info
from cc1 is with "-debug-info-kind={line-tables-only|limited|standalone}"
and "-dwarf-version={2|3|4}". In the absence of a command-line option
to specify Dwarf version, the Toolchain decides it, rather than placing
Toolchain-specific logic in CompilerInvocation.
Also fix a bug in the Windows compatibility argument parsing
in which the "rightmost argument wins" principle failed.
Differential Revision: http://reviews.llvm.org/D13221
llvm-svn: 249655
LLVM r236120 renamed debug info IR constructs to use a `DI` prefix, now
that the `DIDescriptor` hierarchy has been gone for about a week. This
commit was generated using the rename-md-di-nodes.sh upgrade script
attached to PR23080, followed by running clang-format-diff.py on the
`lib/` portion of the patch.
llvm-svn: 236121
This already works, but somewhat by accident (due to the order of
emission in clang, the location is set to the loop header (during the
emission of the iteratior increment) before the loop backedge is
emitted), so let's just add a test for symmetry and future-proofing.
llvm-svn: 216298
Similar to r215768 (which fixed the same case for while loops). To quote
r215768's commit message:
"A little test case simplification - this could be simplified further,
though there are certainly interesting connections to the if/else
construct so I'm hesitant to remove that entirely though it does appear
somewhat unrelated.
(similar fix to r215766, related to PR19864)"
llvm-svn: 216297
A little test case simplification - this could be simplified further,
though there are certainly interesting connections to the if/else
construct so I'm hesitant to remove that entirely though it does appear
somewhat unrelated.
(similar fix to r215766, related to PR19864)
llvm-svn: 215768
This avoids debuggers stepping to strange places (like the last
statement in the loop body, or the first statement in the if).
This is not the whole answer, though - similar bugs no doubt exist in
other loops (patches to follow) and attributing exception handling code
to the correct line is also tricky (based on the previous fix to
PR19864, exception handling is still erroneously attributed to the 'if'
line).
llvm-svn: 215766
This patch flips the default value for -gcolumn-info to be on by
default. I discussed the rationale and provided compile/size data
in:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-June/074290.html
This also updates the documentation and some tests that relied on
the lack of column information. Some tests had column information
in the expected output, but it was wrong (the tsan tests). Others
were using the driver to execute.
llvm-svn: 212781
Since the continuation block of the if statement is emitted within the
condition scope this had the undesirable effect of creating a line table
entry at the end of the then or else statement, a line that may have never
been executed.
PR19864 / rdar://problem/17052973
llvm-svn: 209764
Fangrui Song