[llvm] API for encoding/decoding DWARF discriminators.
Summary:
Added a pair of APIs for encoding/decoding the 3 components of a DWARF discriminator described in http://lists.llvm.org/pipermail/llvm-dev/2016-October/106532.html: the base discriminator, the duplication factor (useful in profile-guided optimization) and the copy index (used to identify copies of code in cases like loop unrolling)
The encoding packs 3 unsigned values in 32 bits. This CL addresses 2 issues:
- communicates overflow back to the user
- supports encoding all 3 components together. Current APIs assume a sequencing of events. For example, creating a new discriminator based on an existing one by changing the base discriminator was not supported.
Reviewers: davidxl, danielcdh, wmi, dblaikie
Reviewed By: dblaikie
Subscribers: zzheng, dmgreen, aprantl, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D55681
llvm-svn: 349973
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
index b5d80f6..e267626 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
@@ -300,8 +300,15 @@
for (BasicBlock *BB : L->getBlocks())
for (Instruction &I : *BB)
if (!isa<DbgInfoIntrinsic>(&I))
- if (const DILocation *DIL = I.getDebugLoc())
- I.setDebugLoc(DIL->cloneWithDuplicationFactor(Count));
+ if (const DILocation *DIL = I.getDebugLoc()) {
+ auto NewDIL = DIL->cloneWithDuplicationFactor(Count);
+ if (NewDIL)
+ I.setDebugLoc(NewDIL.getValue());
+ else
+ LLVM_DEBUG(dbgs()
+ << "Failed to create new discriminator: "
+ << DIL->getFilename() << " Line: " << DIL->getLine());
+ }
// Copy all blocks
for (unsigned It = 1; It != Count; ++It) {