Revert "ADT: Shrink size of SmallVector by 8B on 64-bit platforms"

This reverts commit r337504 while I investigate a TSan bot failure that
seems related:

http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-autoconf/builds/26526

    #8 0x000055581f2895d8 (/b/sanitizer-x86_64-linux-autoconf/build/tsan_debug_build/bin/clang-7+0x1eb45d8)
    #9 0x000055581f294323 llvm::ConstantAggrKeyType<llvm::ConstantArray>::create(llvm::ArrayType*) const /b/sanitizer-x86_64-linux-autoconf/build/llvm/lib/IR/ConstantsContext.h:409:0
    #10 0x000055581f294323 llvm::ConstantUniqueMap<llvm::ConstantArray>::create(llvm::ArrayType*, llvm::ConstantAggrKeyType<llvm::ConstantArray>, std::pair<unsigned int, std::pair<llvm::ArrayType*, llvm::ConstantAggrKeyType<llvm::ConstantArray> > >&) /b/sanitizer-x86_64-linux-autoconf/build/llvm/lib/IR/ConstantsContext.h:635:0
    #11 0x000055581f294323 llvm::ConstantUniqueMap<llvm::ConstantArray>::getOrCreate(llvm::ArrayType*, llvm::ConstantAggrKeyType<llvm::ConstantArray>) /b/sanitizer-x86_64-linux-autoconf/build/llvm/lib/IR/ConstantsContext.h:654:0
    #12 0x000055581f2944cb llvm::ConstantArray::get(llvm::ArrayType*, llvm::ArrayRef<llvm::Constant*>) /b/sanitizer-x86_64-linux-autoconf/build/llvm/lib/IR/Constants.cpp:964:0
    #13 0x000055581fa27e19 llvm::SmallVectorBase::size() const /b/sanitizer-x86_64-linux-autoconf/build/llvm/include/llvm/ADT/SmallVector.h:53:0
    #14 0x000055581fa27e19 llvm::SmallVectorImpl<llvm::Constant*>::resize(unsigned long) /b/sanitizer-x86_64-linux-autoconf/build/llvm/include/llvm/ADT/SmallVector.h:347:0
    #15 0x000055581fa27e19 (anonymous namespace)::EmitArrayConstant(clang::CodeGen::CodeGenModule&, clang::ConstantArrayType const*, llvm::Type*, unsigned int, llvm::SmallVectorImpl<llvm::Constant*>&, llvm::Constant*) /b/sanitizer-x86_64-linux-autoconf/build/llvm/tools/clang/lib/CodeGen/CGExprConstant.cpp:669:0

llvm-svn: 337511

1 files changed, 11 insertions, 14 deletions

diff --git a/llvm/lib/Support/SmallVector.cpp b/llvm/lib/Support/SmallVector.cpp
index 7208572d08d..e8e3498968c 100644
--- a/llvm/lib/Support/SmallVector.cpp
+++ b/llvm/lib/Support/SmallVector.cpp
@@ -15,33 +15,30 @@
 using namespace llvm;
 
 // Check that no bytes are wasted.
-static_assert(sizeof(SmallVector<void *, 1>) ==
-                  sizeof(unsigned) * 2 + sizeof(void *) * 2,
+static_assert(sizeof(SmallVector<void *, 1>) == sizeof(void *) * 4,
               "wasted space in SmallVector size 1; missing EBO?");
 
 /// grow_pod - This is an implementation of the grow() method which only works
 /// on POD-like datatypes and is out of line to reduce code duplication.
-void SmallVectorBase::grow_pod(void *FirstEl, size_t MinCapacity,
+void SmallVectorBase::grow_pod(void *FirstEl, size_t MinSizeInBytes,
                                size_t TSize) {
-  // Ensure we can fit the new capacity in 32 bits.
-  if (MinCapacity > UINT32_MAX)
-    report_bad_alloc_error("SmallVector capacity overflow during allocation");
-
-  size_t NewCapacity = 2 * capacity() + 1; // Always grow.
-  NewCapacity =
-      std::min(std::max(NewCapacity, MinCapacity), size_t(UINT32_MAX));
+  size_t CurSizeBytes = size_in_bytes();
+  size_t NewCapacityInBytes = 2 * capacity_in_bytes() + TSize; // Always grow.
+  if (NewCapacityInBytes < MinSizeInBytes)
+    NewCapacityInBytes = MinSizeInBytes;
 
   void *NewElts;
   if (BeginX == FirstEl) {
-    NewElts = safe_malloc(NewCapacity * TSize);
+    NewElts = safe_malloc(NewCapacityInBytes);
 
     // Copy the elements over.  No need to run dtors on PODs.
-    memcpy(NewElts, this->BeginX, size() * TSize);
+    memcpy(NewElts, this->BeginX, CurSizeBytes);
   } else {
     // If this wasn't grown from the inline copy, grow the allocated space.
-    NewElts = safe_realloc(this->BeginX, NewCapacity * TSize);
+    NewElts = safe_realloc(this->BeginX, NewCapacityInBytes);
   }
 
+  this->EndX = (char*)NewElts+CurSizeBytes;
   this->BeginX = NewElts;
-  this->Capacity = NewCapacity;
+  this->CapacityX = (char*)this->BeginX + NewCapacityInBytes;
 }