[ADT] Pass ArrayRef::slice size_t instead of unsigned.

Also fix slice wrappers drop_front and drop_back.
The unittests are pretty awkward, but do the job; alternatives
welcome!

..and yes, I do have ArrayRefs with more than 4 billion elements.

llvm-svn: 271546

2 files changed, 23 insertions, 8 deletions

diff --git a/llvm/include/llvm/ADT/ArrayRef.h b/llvm/include/llvm/ADT/ArrayRef.h
index 014db620715..95a1e62ef00 100644
--- a/llvm/include/llvm/ADT/ArrayRef.h
+++ b/llvm/include/llvm/ADT/ArrayRef.h
@@ -161,26 +161,26 @@ namespace llvm {
     }
 
     /// slice(n) - Chop off the first N elements of the array.
-    ArrayRef<T> slice(unsigned N) const {
+    ArrayRef<T> slice(size_t N) const {
       assert(N <= size() && "Invalid specifier");
       return ArrayRef<T>(data()+N, size()-N);
     }
 
     /// slice(n, m) - Chop off the first N elements of the array, and keep M
     /// elements in the array.
-    ArrayRef<T> slice(unsigned N, unsigned M) const {
+    ArrayRef<T> slice(size_t N, size_t M) const {
       assert(N+M <= size() && "Invalid specifier");
       return ArrayRef<T>(data()+N, M);
     }
 
     /// \brief Drop the first \p N elements of the array.
-    ArrayRef<T> drop_front(unsigned N = 1) const {
+    ArrayRef<T> drop_front(size_t N = 1) const {
       assert(size() >= N && "Dropping more elements than exist");
       return slice(N, size() - N);
     }
 
     /// \brief Drop the last \p N elements of the array.
-    ArrayRef<T> drop_back(unsigned N = 1) const {
+    ArrayRef<T> drop_back(size_t N = 1) const {
       assert(size() >= N && "Dropping more elements than exist");
       return slice(0, size() - N);
     }
@@ -279,25 +279,25 @@ namespace llvm {
     }
 
     /// slice(n) - Chop off the first N elements of the array.
-    MutableArrayRef<T> slice(unsigned N) const {
+    MutableArrayRef<T> slice(size_t N) const {
       assert(N <= this->size() && "Invalid specifier");
       return MutableArrayRef<T>(data()+N, this->size()-N);
     }
 
     /// slice(n, m) - Chop off the first N elements of the array, and keep M
     /// elements in the array.
-    MutableArrayRef<T> slice(unsigned N, unsigned M) const {
+    MutableArrayRef<T> slice(size_t N, size_t M) const {
       assert(N+M <= this->size() && "Invalid specifier");
       return MutableArrayRef<T>(data()+N, M);
     }
 
     /// \brief Drop the first \p N elements of the array.
-    MutableArrayRef<T> drop_front(unsigned N = 1) const {
+    MutableArrayRef<T> drop_front(size_t N = 1) const {
       assert(this->size() >= N && "Dropping more elements than exist");
       return slice(N, this->size() - N);
     }
 
-    MutableArrayRef<T> drop_back(unsigned N = 1) const {
+    MutableArrayRef<T> drop_back(size_t N = 1) const {
       assert(this->size() >= N && "Dropping more elements than exist");
       return slice(0, this->size() - N);
     }
diff --git a/llvm/unittests/ADT/ArrayRefTest.cpp b/llvm/unittests/ADT/ArrayRefTest.cpp
index 5a1ff785c34..b5b71f06f65 100644
--- a/llvm/unittests/ADT/ArrayRefTest.cpp
+++ b/llvm/unittests/ADT/ArrayRefTest.cpp
@@ -65,6 +65,10 @@ TEST(ArrayRefTest, DropBack) {
   ArrayRef<int> AR1(TheNumbers);
   ArrayRef<int> AR2(TheNumbers, AR1.size() - 1);
   EXPECT_TRUE(AR1.drop_back().equals(AR2));
+
+  // Check that drop_back accepts size_t-sized numbers.
+  ArrayRef<char> AR3((const char *)0x10000, SIZE_MAX - 0x10000);
+  EXPECT_EQ(1U, AR3.drop_back(AR3.size() - 1).size());
 }
 
 TEST(ArrayRefTest, DropFront) {
@@ -72,6 +76,10 @@ TEST(ArrayRefTest, DropFront) {
   ArrayRef<int> AR1(TheNumbers);
   ArrayRef<int> AR2(&TheNumbers[2], AR1.size() - 2);
   EXPECT_TRUE(AR1.drop_front(2).equals(AR2));
+
+  // Check that drop_front accepts size_t-sized numbers.
+  ArrayRef<char> AR3((const char *)0x10000, SIZE_MAX - 0x10000);
+  EXPECT_EQ(1U, AR3.drop_front(AR3.size() - 1).size());
 }
 
 TEST(ArrayRefTest, Equals) {
@@ -101,6 +109,13 @@ TEST(ArrayRefTest, EmptyEquals) {
   EXPECT_TRUE(ArrayRef<unsigned>() == ArrayRef<unsigned>());
 }
 
+TEST(ArrayRefTest, Slice) {
+  // Check that slice accepts size_t-sized numbers.
+  ArrayRef<char> AR((const char *)0x10000, SIZE_MAX - 0x10000);
+  EXPECT_EQ(1U, AR.slice(AR.size() - 1).size());
+  EXPECT_EQ(AR.size() - 1, AR.slice(1, AR.size() - 1).size());
+}
+
 TEST(ArrayRefTest, ConstConvert) {
   int buf[4];
   for (int i = 0; i < 4; ++i)