[llvm] [DebugInfo][RemoveDIs] Erase ranges of instructions individually (PR #81007)

[Jeremy Morse via llvm-commits]

https://github.com/jmorse created https://github.com/llvm/llvm-project/pull/81007

The BasicBlock::erase method simply removes a range of instructions from the instlist by unlinking them. However, now that we're attaching debug-info directly to instructions, some cleanup is required, so use eraseFromParent on each instruction instead.

This is less efficient, but rare, and seemingly only WASM EH Prepare uses this method of BasicBlock. Detected via a memory leak check in asan.

(asan is always the final boss for whatever I do).

>From bde5e4aa299df2ec3122d639b6a79002fc8ac9d5 Mon Sep 17 00:00:00 2001
From: Jeremy Morse <jeremy.morse at sony.com>
Date: Wed, 7 Feb 2024 15:51:23 +0000
Subject: [PATCH] [DebugInfo][RemoveDIs] Erase ranges of instructions
 individually

The BasicBlock::erase method simply removes a range of instructions from
the instlist by unlinking them. However, now that we're attaching
debug-info directly to instructions, some cleanup is required, so use
eraseFromParent on each instruction instead.

This is less efficient, but rare, and seemingly only WASM EH Prepare uses
this method of BasicBlock. Detected via a memory leak check in asan.
---
 llvm/lib/IR/BasicBlock.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/IR/BasicBlock.cpp b/llvm/lib/IR/BasicBlock.cpp
index dca5283283847..0f89a8d8c8928 100644
--- a/llvm/lib/IR/BasicBlock.cpp
+++ b/llvm/lib/IR/BasicBlock.cpp
@@ -675,7 +675,9 @@ BasicBlock *BasicBlock::splitBasicBlockBefore(iterator I, const Twine &BBName) {
 
 BasicBlock::iterator BasicBlock::erase(BasicBlock::iterator FromIt,
                                        BasicBlock::iterator ToIt) {
-  return InstList.erase(FromIt, ToIt);
+  for (Instruction &I : make_early_inc_range(make_range(FromIt, ToIt)))
+    I.eraseFromParent();
+  return ToIt;
 }
 
 void BasicBlock::replacePhiUsesWith(BasicBlock *Old, BasicBlock *New) {