Delay initialization of three static global maps, NFC

This avoids allocating a few KB of heap memory on startup, and instead
allocates these maps lazily. I noticed this while profiling LLD.

llvm-svn: 357192

1 files changed, 55 insertions, 56 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Native/PDBStringTableBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/PDBStringTableBuilder.cpp
index b2ae1188bb1..4b69e09a83d 100644
--- a/llvm/lib/DebugInfo/PDB/Native/PDBStringTableBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/PDBStringTableBuilder.cpp
@@ -49,63 +49,62 @@ StringRef PDBStringTableBuilder::getStringForId(uint32_t Id) const {
   return Strings.getStringForId(Id);
 }
 
-// This is a precomputed list of Buckets given the specified number of
-// strings.  Matching the reference algorithm exactly is not strictly
-// necessary for correctness, but it helps when comparing LLD's PDBs with
-// Microsoft's PDBs so as to eliminate superfluous differences.
-static std::map<uint32_t, uint32_t> StringsToBuckets = {
-    {1, 2},
-    {2, 4},
-    {4, 7},
-    {6, 11},
-    {9, 17},
-    {13, 26},
-    {20, 40},
-    {31, 61},
-    {46, 92},
-    {70, 139},
-    {105, 209},
-    {157, 314},
-    {236, 472},
-    {355, 709},
-    {532, 1064},
-    {799, 1597},
-    {1198, 2396},
-    {1798, 3595},
-    {2697, 5393},
-    {4045, 8090},
-    {6068, 12136},
-    {9103, 18205},
-    {13654, 27308},
-    {20482, 40963},
-    {30723, 61445},
-    {46084, 92168},
-    {69127, 138253},
-    {103690, 207380},
-    {155536, 311071},
-    {233304, 466607},
-    {349956, 699911},
-    {524934, 1049867},
-    {787401, 1574801},
-    {1181101, 2362202},
-    {1771652, 3543304},
-    {2657479, 5314957},
-    {3986218, 7972436},
-    {5979328, 11958655},
-    {8968992, 17937983},
-    {13453488, 26906975},
-    {20180232, 40360463},
-    {30270348, 60540695},
-    {45405522, 90811043},
-    {68108283, 136216565},
-    {102162424, 204324848},
-    {153243637, 306487273},
-    {229865455, 459730910},
-    {344798183, 689596366},
-    {517197275, 1034394550},
-    {775795913, 1551591826}};
-
 static uint32_t computeBucketCount(uint32_t NumStrings) {
+  // This is a precomputed list of Buckets given the specified number of
+  // strings.  Matching the reference algorithm exactly is not strictly
+  // necessary for correctness, but it helps when comparing LLD's PDBs with
+  // Microsoft's PDBs so as to eliminate superfluous differences.
+  static std::map<uint32_t, uint32_t> StringsToBuckets = {
+      {1, 2},
+      {2, 4},
+      {4, 7},
+      {6, 11},
+      {9, 17},
+      {13, 26},
+      {20, 40},
+      {31, 61},
+      {46, 92},
+      {70, 139},
+      {105, 209},
+      {157, 314},
+      {236, 472},
+      {355, 709},
+      {532, 1064},
+      {799, 1597},
+      {1198, 2396},
+      {1798, 3595},
+      {2697, 5393},
+      {4045, 8090},
+      {6068, 12136},
+      {9103, 18205},
+      {13654, 27308},
+      {20482, 40963},
+      {30723, 61445},
+      {46084, 92168},
+      {69127, 138253},
+      {103690, 207380},
+      {155536, 311071},
+      {233304, 466607},
+      {349956, 699911},
+      {524934, 1049867},
+      {787401, 1574801},
+      {1181101, 2362202},
+      {1771652, 3543304},
+      {2657479, 5314957},
+      {3986218, 7972436},
+      {5979328, 11958655},
+      {8968992, 17937983},
+      {13453488, 26906975},
+      {20180232, 40360463},
+      {30270348, 60540695},
+      {45405522, 90811043},
+      {68108283, 136216565},
+      {102162424, 204324848},
+      {153243637, 306487273},
+      {229865455, 459730910},
+      {344798183, 689596366},
+      {517197275, 1034394550},
+      {775795913, 1551591826}};
   auto Entry = StringsToBuckets.lower_bound(NumStrings);
   assert(Entry != StringsToBuckets.end());
   return Entry->second;