This patch re-implements a variety of debug-info maintenence functions
to use DPValues instead of DbgValueInst's: supporting the "new"
non-intrinsic representation of debug-info. As per [0], we need to have
parallel implementations of various utilities for a time, and these are
the most fundamental utilities used throughout the compiler.
I've added --try-experimental-debuginfo-iterators to a variety of RUN
lines: this is a flag that turns on "new debug-info" if it's built into
LLVM, and not otherwise. This should ensure that we have the same
behaviour for the same IR inputs, but using a different internal
representation. For the most part these changes affect SROA/Mem2Reg
promotion of dbg.declares into dbg.value intrinsics (now DPValues),
we're leaving dbg.declares as instructions until later in the day.
There's also some salvaging changes made.
I believe the tests that I've added cover almost all the code being
updated here. The only thing I'm not confident about is SimplifyCFG,
which calls rewriteDebugUsers down a variety of code paths. Those
changes can't immediately get full coverage as an additional patch is
needed that updates handling of Unreachable instructions, will upload
that shortly.
[0]
https://discourse.llvm.org/t/rfc-instruction-api-changes-needed-to-eliminate-debug-intrinsics-from-ir/68939/9
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
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
Track the debug locations of the incoming values to newly-created phis,
and apply merged debug locations to the phis.
A merged location will be on line 0, but will have the correct scope
set. This improves crash reporting when an inlined instruction with a
merged location triggers a machine exception. A debugger will be able to
narrow down the crash to the correct inlined scope, instead of simply
pointing to the outer scope of the caller.
Taken together with a change allows generating merged line-0 locations
for instructions which aren't calls, this results in a 0.5% increase in
the uncompressed size of the .debug_line section of a stage2+Release
build of clang (-O3 -g).
rdar://33858697
Differential Revision: https://reviews.llvm.org/D45397
llvm-svn: 330227
