[MemProf] Avoid assertion checking loop under NDEBUG (NFC)

[teresajohnson]

Guard a loop that only exists to do assertion checking of stack ids on
memprof metadata so that it isn't compiled and executed under NDEBUG.
This is similar to how callsite metadata stack id verification is
guarded further below.

[llvmbot]

@llvm/pr-subscribers-llvm-analysis

@llvm/pr-subscribers-llvm-transforms

Author: Teresa Johnson (teresajohnson)

Changes

Guard a loop that only exists to do assertion checking of stack ids on
memprof metadata so that it isn't compiled and executed under NDEBUG.
This is similar to how callsite metadata stack id verification is
guarded further below.

---

Full diff: https://github.com/llvm/llvm-project/pull/138985.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp (+2)

diff --git a/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp b/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
index ec158afb76519..567f0acadbd2d 100644
--- a/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
+++ b/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
@@ -5242,6 +5242,7 @@ bool MemProfContextDisambiguation::applyImport(Module &M) {
           assert(AI != FS->allocs().end());
           auto &AllocNode = *(AI++);
 
+#ifndef NDEBUG
           // Sanity check that the MIB stack ids match between the summary and
           // instruction metadata.
           auto MIBIter = AllocNode.MIBs.begin();
@@ -5276,6 +5277,7 @@ bool MemProfContextDisambiguation::applyImport(Module &M) {
             }
             MIBIter++;
           }
+#endif
 
           // Perform cloning if not yet done.
           CloneFuncIfNeeded(/*NumClones=*/AllocNode.Versions.size());

[snehasish]

Can we refactor this out to a static helper? I think it should be straightforward since the only live ins for this region are AllocNode and MemProfMD as far as I can tell.

[teresajohnson]

Done. There were a couple of other live in variables. I also updated one of the methods to take a const to enable using const for the new helper.

[snehasish]

lgtm

[snehasish]

I think we can drop the ifndef around the function definition in favour of a LLVM_ATTRIBUTE_UNUSED function attribute?

[teresajohnson]

I could, but then I need to put that attribute back on the StackIdIndexIter def in this code that I had removed it from. My sense is that the #ifdef is simpler overall, wdyt?

[snehasish]

Sounds good to me