In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
There is no situation where this rarely-used argument cannot be
substituted with a DIExpression and removing it allows us to simplify
the DWARF backend. Note that this patch does not yet remove any of
the newly dead code.
rdar://problem/33580047
Differential Revision: https://reviews.llvm.org/D35951
llvm-svn: 309426
Summary:
In fuctions that contained debug info but were empty otherwise,
the ARM load/store optimizer could abort. This was because
function MergeReturnIntoLDM handled the special case where a
Machine Basic BLock is empty by calling MBB.empty(). However, this
returns false in presence of debug info, although the function
should be considered empty in the eyes of the load/store optimizer.
This has been fixed by handling the case where searching through the
block finds only debug instructions.
Reviewers: rengolin, dexonsmith, llvm-commits, jmolloy
Subscribers: t.p.northover, aemerson, rengolin, samparker
Differential Revision: https://reviews.llvm.org/D23847
llvm-svn: 279820
Shiva Chen