[llvm] 2d53aab - In-class initialize DenseMapBase members. (#177168)

[via llvm-commits]

Author: Matt Davis
Date: 2026-02-12T10:24:04-05:00
New Revision: 2d53aab859de707d332119a910440169a518062f

URL: https://github.com/llvm/llvm-project/commit/2d53aab859de707d332119a910440169a518062f
DIFF: https://github.com/llvm/llvm-project/commit/2d53aab859de707d332119a910440169a518062f.diff

LOG: In-class initialize DenseMapBase members. (#177168)

I've seen a number of false positive defects in Coverity regarding
uninitialized instances of some of these members. I've decided to
in-class initialize 3 scalar members of `DenseMapBase` to hopefully
silence Coverity.

Since the initialization is performed through `initWithExactBucketCount`
I think it makes sense to just zero init them. I assume the original
intent was to avoid some initialization overhead; however, that seems
negligible from my last compile-time tracker results (If I'm reading the
results correctly).

I do see some of the insn size percentages jump around but that might be
noise. I had run an earlier compile time tracker on the same data, and I
think the timing results were a bit different, the most recent run
information is below.

Compile time tracker is showing the following output:
Metric | Old | New
-- | -- | --
instructions:u | 35718151M | 35718325M (+0.00%)
wall-time | 614.01s | 613.82s (-0.03%)
size-file | 132278KiB | 132278KiB (+0.00%)
size-file (stage1) | 151065KiB | 151065KiB (-0.00%)

clang build:
Metric	Old	New

[instructions:u](https://llvm-compile-time-tracker.com/compare_clang.php?from=f97f53e1d925fe702c23ad3a120ad3ab40b4eb51&to=d925643ace32566ea76a60d0642180d077f476f5&stat=instructions%3Au)
35718151M 35718325M (+0.00%)

[wall-time](https://llvm-compile-time-tracker.com/compare_clang.php?from=f97f53e1d925fe702c23ad3a120ad3ab40b4eb51&to=d925643ace32566ea76a60d0642180d077f476f5&stat=wall-time)
614.01s 613.82s (-0.03%)

[size-file](https://llvm-compile-time-tracker.com/compare_clang.php?from=f97f53e1d925fe702c23ad3a120ad3ab40b4eb51&to=d925643ace32566ea76a60d0642180d077f476f5&stat=size-file)
132278KiB 132278KiB (+0.00%)
size-file (stage1)	151065KiB	151065KiB (-0.00%)`

Added: 
    

Modified: 
    llvm/include/llvm/ADT/DenseMap.h

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/ADT/DenseMap.h b/llvm/include/llvm/ADT/DenseMap.h
index fe8868619730e..d967a231804f6 100644
--- a/llvm/include/llvm/ADT/DenseMap.h
+++ b/llvm/include/llvm/ADT/DenseMap.h
@@ -751,10 +751,10 @@ class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
   // simplicity of referring to them.
   using BaseT = DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
 
-  BucketT *Buckets;
-  unsigned NumEntries;
-  unsigned NumTombstones;
-  unsigned NumBuckets;
+  BucketT *Buckets = nullptr;
+  unsigned NumEntries = 0;
+  unsigned NumTombstones = 0;
+  unsigned NumBuckets = 0;
 
   explicit DenseMap(unsigned NumBuckets, typename BaseT::ExactBucketCount) {
     this->initWithExactBucketCount(NumBuckets);