From: Argyrios Kyrtzidis <akyrtzi@gmail.com>
Date: Thu, 28 Apr 2011 18:53:55 +0000 (+0000)
Subject: Don't waste memory if the initializer expression is empty.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f8b1771677743d24c7391305cad8853c513ec0f8;p=clang

Don't waste memory if the initializer expression is empty.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130420 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 0cf7546466..938ace851e 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -1795,11 +1795,15 @@ InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
   // Pre-allocate storage for the structured initializer list.
   unsigned NumElements = 0;
   unsigned NumInits = 0;
-  if (!StructuredList)
+  bool GotNumInits = false;
+  if (!StructuredList) {
     NumInits = IList->getNumInits();
-  else if (Index < IList->getNumInits()) {
-    if (InitListExpr *SubList = dyn_cast<InitListExpr>(IList->getInit(Index)))
+    GotNumInits = true;
+  } else if (Index < IList->getNumInits()) {
+    if (InitListExpr *SubList = dyn_cast<InitListExpr>(IList->getInit(Index))) {
       NumInits = SubList->getNumInits();
+      GotNumInits = true;
+    }
   }
 
   if (const ArrayType *AType
@@ -1808,7 +1812,7 @@ InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
       NumElements = CAType->getSize().getZExtValue();
       // Simple heuristic so that we don't allocate a very large
       // initializer with many empty entries at the end.
-      if (NumInits && NumElements > NumInits)
+      if (GotNumInits && NumElements > NumInits)
         NumElements = 0;
     }
   } else if (const VectorType *VType = CurrentObjectType->getAs<VectorType>())
diff --git a/test/Index/initializer-memory.cpp b/test/Index/initializer-memory.cpp
index d0f531fdd2..f085c35624 100644
--- a/test/Index/initializer-memory.cpp
+++ b/test/Index/initializer-memory.cpp
@@ -3,6 +3,7 @@
 // rdar://9275920 - We would create millions of Exprs to fill out the initializer.
 
 double data[1000000] = {0};
+double data_empty_init[1000000] = {};
 
 struct S {
  S(int);
@@ -10,5 +11,6 @@ struct S {
 };
 
 S data2[1000000] = {0};
+S data_empty_init2[1000000] = {};
 
 // CHECK: TOTAL = {{.*}} (0.{{.*}} MBytes)