[llvm] c2a2fd2 - [DebugInfo][RemoveDIs] Allow for inserting DPValues at end() (#72379)

[via llvm-commits]

Author: Jeremy Morse
Date: 2023-11-15T15:55:34Z
New Revision: c2a2fd209e2da4c80e55d11b114d47b8d1eaaa16

URL: https://github.com/llvm/llvm-project/commit/c2a2fd209e2da4c80e55d11b114d47b8d1eaaa16
DIFF: https://github.com/llvm/llvm-project/commit/c2a2fd209e2da4c80e55d11b114d47b8d1eaaa16.diff

LOG: [DebugInfo][RemoveDIs] Allow for inserting DPValues at end() (#72379)

This trivial patch covers a bit of fallout from
https://reviews.llvm.org/D153990, where we moved the storage of trailing
DPValues into LLVMContext rather than being stored in each block. As a
result, you can now get a null DPMarker pointer from the end() iterator
where previously you didn't (and now it has to be explicitly created).

This is a sort-of stopgap measure -- there's another all-singing
all-dancing patch further down the line that refactors all of this so
that we don't allocate a DPMarker for every single Instruction. When
that lands this will all be refactored so that every time we request a
DPMarker, one is created if needs be. That's a performance-fix rather
than a functionality related patch though, so it'll come later.

Added: 
    

Modified: 
    llvm/lib/IR/Instruction.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/IR/Instruction.cpp b/llvm/lib/IR/Instruction.cpp
index 27b2c5ee4d399dc..7449692f05d7bf9 100644
--- a/llvm/lib/IR/Instruction.cpp
+++ b/llvm/lib/IR/Instruction.cpp
@@ -146,6 +146,8 @@ void Instruction::insertBefore(BasicBlock &BB,
   bool InsertAtHead = InsertPos.getHeadBit();
   if (!InsertAtHead) {
     DPMarker *SrcMarker = BB.getMarker(InsertPos);
+    if (!SrcMarker)
+      SrcMarker = BB.createMarker(InsertPos);
     DbgMarker->absorbDebugValues(*SrcMarker, false);
   }