[Alignment][NFC] Move and type functions from MathExtras to Alignment

Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68942

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374773 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/Alignment.h

@@ -154,6 +154,11 @@ inline bool isAligned(MaybeAlign Lhs, uint64_t SizeInBytes) {
   return SizeInBytes % (*Lhs).value() == 0;
 }
 
+/// Checks that Addr is a multiple of the alignment.
+inline bool isAddrAligned(Align Lhs, const void *Addr) {
+  return isAligned(Lhs, reinterpret_cast<uintptr_t>(Addr));
+}
+
 /// Returns a multiple of A needed to store `Size` bytes.
 inline uint64_t alignTo(uint64_t Size, Align A) {
   return (Size + A.value() - 1) / A.value() * A.value();
@@ -165,12 +170,25 @@ inline uint64_t alignTo(uint64_t Size, MaybeAlign A) {
   return A ? alignTo(Size, A.getValue()) : Size;
 }
 
+/// Aligns `Addr` to `Alignment` bytes, rounding up.
+inline uintptr_t alignAddr(const void *Addr, Align Alignment) {
+  uintptr_t ArithAddr = reinterpret_cast<uintptr_t>(Addr);
+  assert(ArithAddr + Alignment.value() - 1 >= ArithAddr && "Overflow");
+  return alignTo(ArithAddr, Alignment);
+}
+
 /// Returns the offset to the next integer (mod 2**64) that is greater than
 /// or equal to \p Value and is a multiple of \p Align.
 inline uint64_t offsetToAlignment(uint64_t Value, Align Alignment) {
   return alignTo(Value, Alignment) - Value;
 }
 
+/// Returns the necessary adjustment for aligning `Addr` to `Alignment`
+/// bytes, rounding up.
+inline uint64_t offsetToAlignedAddr(const void *Addr, Align Alignment) {
+  return offsetToAlignment(reinterpret_cast<uintptr_t>(Addr), Alignment);
+}
+
 /// Returns the log2 of the alignment.
 inline unsigned Log2(Align A) { return A.ShiftValue; }
 

include/llvm/Support/Allocator.h

@@ -22,6 +22,7 @@
 
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Alignment.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
@@ -211,13 +212,11 @@ class BumpPtrAllocatorImpl
 
   /// Allocate space at the specified alignment.
   LLVM_ATTRIBUTE_RETURNS_NONNULL LLVM_ATTRIBUTE_RETURNS_NOALIAS void *
-  Allocate(size_t Size, size_t Alignment) {
-    assert(Alignment > 0 && "0-byte alignnment is not allowed. Use 1 instead.");
-
+  Allocate(size_t Size, Align Alignment) {
     // Keep track of how many bytes we've allocated.
     BytesAllocated += Size;
 
-    size_t Adjustment = alignmentAdjustment(CurPtr, Alignment);
+    size_t Adjustment = offsetToAlignedAddr(CurPtr, Alignment);
     assert(Adjustment + Size >= Size && "Adjustment + Size must not overflow");
 
     size_t SizeToAllocate = Size;
@@ -240,7 +239,7 @@ class BumpPtrAllocatorImpl
     }
 
     // If Size is really big, allocate a separate slab for it.
-    size_t PaddedSize = SizeToAllocate + Alignment - 1;
+    size_t PaddedSize = SizeToAllocate + Alignment.value() - 1;
     if (PaddedSize > SizeThreshold) {
       void *NewSlab = Allocator.Allocate(PaddedSize, 0);
       // We own the new slab and don't want anyone reading anyting other than
@@ -268,6 +267,12 @@ class BumpPtrAllocatorImpl
     return AlignedPtr;
   }
 
+  inline LLVM_ATTRIBUTE_RETURNS_NONNULL LLVM_ATTRIBUTE_RETURNS_NOALIAS void *
+  Allocate(size_t Size, size_t Alignment) {
+    assert(Alignment > 0 && "0-byte alignnment is not allowed. Use 1 instead.");
+    return Allocate(Size, Align(Alignment));
+  }
+
   // Pull in base class overloads.
   using AllocatorBase<BumpPtrAllocatorImpl>::Allocate;
 
@@ -461,7 +466,7 @@ template <typename T> class SpecificBumpPtrAllocator {
   /// all memory allocated so far.
   void DestroyAll() {
     auto DestroyElements = [](char *Begin, char *End) {
-      assert(Begin == (char *)alignAddr(Begin, alignof(T)));
+      assert(Begin == (char *)alignAddr(Begin, Align::Of<T>()));
       for (char *Ptr = Begin; Ptr + sizeof(T) <= End; Ptr += sizeof(T))
         reinterpret_cast<T *>(Ptr)->~T();
     };
@@ -470,7 +475,7 @@ template <typename T> class SpecificBumpPtrAllocator {
          ++I) {
       size_t AllocatedSlabSize = BumpPtrAllocator::computeSlabSize(
           std::distance(Allocator.Slabs.begin(), I));
-      char *Begin = (char *)alignAddr(*I, alignof(T));
+      char *Begin = (char *)alignAddr(*I, Align::Of<T>());
       char *End = *I == Allocator.Slabs.back() ? Allocator.CurPtr
                                                : (char *)*I + AllocatedSlabSize;
 
@@ -480,7 +485,8 @@ template <typename T> class SpecificBumpPtrAllocator {
     for (auto &PtrAndSize : Allocator.CustomSizedSlabs) {
       void *Ptr = PtrAndSize.first;
       size_t Size = PtrAndSize.second;
-      DestroyElements((char *)alignAddr(Ptr, alignof(T)), (char *)Ptr + Size);
+      DestroyElements((char *)alignAddr(Ptr, Align::Of<T>()),
+                      (char *)Ptr + Size);
     }
 
     Allocator.Reset();

include/llvm/Support/BinaryStreamArray.h

@@ -286,7 +286,7 @@ template <typename T> class FixedStreamArray {
       // an exact multiple of the element size.
       consumeError(std::move(EC));
     }
-    assert(llvm::alignmentAdjustment(Data.data(), alignof(T)) == 0);
+    assert(isAddrAligned(Align::Of<T>(), Data.data()));
     return *reinterpret_cast<const T *>(Data.data());
   }
 

include/llvm/Support/BinaryStreamReader.h

@@ -198,7 +198,7 @@ class BinaryStreamReader {
     if (auto EC = readBytes(Bytes, NumElements * sizeof(T)))
       return EC;
 
-    assert(alignmentAdjustment(Bytes.data(), alignof(T)) == 0 &&
+    assert(isAddrAligned(Align::Of<T>(), Bytes.data()) &&
            "Reading at invalid alignment!");
 
     Array = ArrayRef<T>(reinterpret_cast<const T *>(Bytes.data()), NumElements);

include/llvm/Support/MathExtras.h

@@ -667,25 +667,6 @@ constexpr inline uint64_t MinAlign(uint64_t A, uint64_t B) {
   return (A | B) & (1 + ~(A | B));
 }
 
-/// Aligns \c Addr to \c Alignment bytes, rounding up.
-///
-/// Alignment should be a power of two.  This method rounds up, so
-/// alignAddr(7, 4) == 8 and alignAddr(8, 4) == 8.
-inline uintptr_t alignAddr(const void *Addr, size_t Alignment) {
-  assert(Alignment && isPowerOf2_64((uint64_t)Alignment) &&
-         "Alignment is not a power of two!");
-
-  assert((uintptr_t)Addr + Alignment - 1 >= (uintptr_t)Addr);
-
-  return (((uintptr_t)Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1));
-}
-
-/// Returns the necessary adjustment for aligning \c Ptr to \c Alignment
-/// bytes, rounding up.
-inline size_t alignmentAdjustment(const void *Ptr, size_t Alignment) {
-  return alignAddr(Ptr, Alignment) - (uintptr_t)Ptr;
-}
-
 /// Returns the next power of two (in 64-bits) that is strictly greater than A.
 /// Returns zero on overflow.
 inline uint64_t NextPowerOf2(uint64_t A) {

include/llvm/Support/TrailingObjects.h

@@ -47,6 +47,7 @@
 #define LLVM_SUPPORT_TRAILINGOBJECTS_H
 
 #include "llvm/Support/AlignOf.h"
+#include "llvm/Support/Alignment.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/type_traits.h"
@@ -167,7 +168,7 @@ class TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, PrevTy, NextTy,
 
     if (requiresRealignment())
       return reinterpret_cast<const NextTy *>(
-          llvm::alignAddr(Ptr, alignof(NextTy)));
+          alignAddr(Ptr, Align::Of<NextTy>()));
     else
       return reinterpret_cast<const NextTy *>(Ptr);
   }
@@ -181,7 +182,7 @@ class TrailingObjectsImpl<Align, BaseTy, TopTrailingObj, PrevTy, NextTy,
                     Obj, TrailingObjectsBase::OverloadToken<PrevTy>());
 
     if (requiresRealignment())
-      return reinterpret_cast<NextTy *>(llvm::alignAddr(Ptr, alignof(NextTy)));
+      return reinterpret_cast<NextTy *>(alignAddr(Ptr, Align::Of<NextTy>()));
     else
       return reinterpret_cast<NextTy *>(Ptr);
   }

lib/ProfileData/Coverage/CoverageMappingReader.cpp

@@ -506,7 +506,7 @@ class VersionedCovMapFuncRecordReader : public CovMapFuncRecordReader {
       return make_error<CoverageMapError>(coveragemap_error::malformed);
     // Each coverage map has an alignment of 8, so we need to adjust alignment
     // before reading the next map.
-    Buf += alignmentAdjustment(Buf, 8);
+    Buf += offsetToAlignedAddr(Buf, Align(8));
 
     auto CFR = reinterpret_cast<const FuncRecordType *>(FunBuf);
     while ((const char *)CFR < FunEnd) {
@@ -648,7 +648,7 @@ loadTestingFormat(StringRef Data) {
   // Skip the padding bytes because coverage map data has an alignment of 8.
   if (CoverageMapping.empty())
     return make_error<CoverageMapError>(coveragemap_error::truncated);
-  size_t Pad = alignmentAdjustment(CoverageMapping.data(), 8);
+  size_t Pad = offsetToAlignedAddr(CoverageMapping.data(), Align(8));
   if (CoverageMapping.size() < Pad)
     return make_error<CoverageMapError>(coveragemap_error::malformed);
   CoverageMapping = CoverageMapping.substr(Pad);

lib/Support/Unix/Memory.inc

@@ -176,16 +176,16 @@ Memory::releaseMappedMemory(MemoryBlock &M) {
 
 std::error_code
 Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
-  static const size_t PageSize = Process::getPageSizeEstimate();
+  static const Align PageSize = Align(Process::getPageSizeEstimate());
   if (M.Address == nullptr || M.AllocatedSize == 0)
     return std::error_code();
 
   if (!Flags)
     return std::error_code(EINVAL, std::generic_category());
 
   int Protect = getPosixProtectionFlags(Flags);
-  uintptr_t Start = alignAddr((uint8_t *)M.Address - PageSize + 1, PageSize);
-  uintptr_t End = alignAddr((uint8_t *)M.Address + M.AllocatedSize, PageSize);
+  uintptr_t Start = alignAddr((const uint8_t *)M.Address - PageSize.value() + 1, PageSize);
+  uintptr_t End = alignAddr((const uint8_t *)M.Address + M.AllocatedSize, PageSize);
 
   bool InvalidateCache = (Flags & MF_EXEC);
 

unittests/Support/AlignmentTest.cpp

@@ -90,6 +90,11 @@ TEST(AlignmentTest, AlignTo) {
     uint64_t alignment;
     uint64_t offset;
     uint64_t rounded;
+    const void *forgedAddr() const {
+      //  A value of any integral or enumeration type can be converted to a
+      //  pointer type.
+      return reinterpret_cast<const void *>(offset);
+    }
   } kTests[] = {
       // MaybeAlign
       {0, 0, 0},
@@ -116,6 +121,7 @@ TEST(AlignmentTest, AlignTo) {
     // Test Align
     if (A) {
       EXPECT_EQ(alignTo(T.offset, A.getValue()), T.rounded);
+      EXPECT_EQ(alignAddr(T.forgedAddr(), A.getValue()), T.rounded);
     }
   }
 }
@@ -174,13 +180,17 @@ TEST(AlignmentTest, Encode_Decode) {
   EXPECT_EQ(Expected, Actual);
 }
 
-TEST(AlignmentTest, isAligned) {
+TEST(AlignmentTest, isAligned_isAddrAligned) {
   struct {
     uint64_t alignment;
     uint64_t offset;
     bool isAligned;
+    const void *forgedAddr() const {
+      //  A value of any integral or enumeration type can be converted to a
+      //  pointer type.
+      return reinterpret_cast<const void *>(offset);
+    }
   } kTests[] = {
-      // MaybeAlign / Align
       {1, 0, true},  {1, 1, true},  {1, 5, true},  {2, 0, true},
       {2, 1, false}, {2, 2, true},  {2, 7, false}, {2, 16, true},
       {4, 0, true},  {4, 1, false}, {4, 4, true},  {4, 6, false},
@@ -192,10 +202,32 @@ TEST(AlignmentTest, isAligned) {
     // Test Align
     if (A) {
       EXPECT_EQ(isAligned(A.getValue(), T.offset), T.isAligned);
+      EXPECT_EQ(isAddrAligned(A.getValue(), T.forgedAddr()), T.isAligned);
     }
   }
 }
 
+TEST(AlignmentTest, offsetToAlignment) {
+  struct {
+    uint64_t alignment;
+    uint64_t offset;
+    uint64_t alignedOffset;
+    const void *forgedAddr() const {
+      //  A value of any integral or enumeration type can be converted to a
+      //  pointer type.
+      return reinterpret_cast<const void *>(offset);
+    }
+  } kTests[] = {
+      {1, 0, 0}, {1, 1, 0},  {1, 5, 0}, {2, 0, 0}, {2, 1, 1}, {2, 2, 0},
+      {2, 7, 1}, {2, 16, 0}, {4, 0, 0}, {4, 1, 3}, {4, 4, 0}, {4, 6, 2},
+  };
+  for (const auto &T : kTests) {
+    const Align A(T.alignment);
+    EXPECT_EQ(offsetToAlignment(T.offset, A), T.alignedOffset);
+    EXPECT_EQ(offsetToAlignedAddr(T.forgedAddr(), A), T.alignedOffset);
+  }
+}
+
 TEST(AlignmentTest, AlignComparisons) {
   std::vector<uint64_t> ValidAlignments = getValidAlignments();
   std::sort(ValidAlignments.begin(), ValidAlignments.end());
@@ -349,6 +381,12 @@ TEST(AlignmentDeathTest, CompareAlignToUndefMaybeAlign) {
   }
 }
 
+TEST(AlignmentDeathTest, AlignAddr) {
+  const void *const unaligned_high_ptr =
+      reinterpret_cast<const void *>(std::numeric_limits<uintptr_t>::max() - 1);
+  EXPECT_DEATH(alignAddr(unaligned_high_ptr, Align(16)), "Overflow");
+}
+
 #endif // NDEBUG
 
 } // end anonymous namespace

unittests/Support/AllocatorTest.cpp

@@ -145,8 +145,8 @@ class MockSlabAllocator {
   void *Allocate(size_t Size, size_t /*Alignment*/) {
     // Allocate space for the alignment, the slab, and a void* that goes right
     // before the slab.
-    size_t Alignment = 4096;
-    void *MemBase = safe_malloc(Size + Alignment - 1 + sizeof(void*));
+    Align Alignment(4096);
+    void *MemBase = safe_malloc(Size + Alignment.value() - 1 + sizeof(void *));
 
     // Find the slab start.
     void *Slab = (void *)alignAddr((char*)MemBase + sizeof(void *), Alignment);

unittests/Support/TrailingObjectsTest.cpp

@@ -232,7 +232,7 @@ TEST(TrailingObjects, Realignment) {
   EXPECT_EQ(C->getTrailingObjects<char>(), reinterpret_cast<char *>(C + 1));
   EXPECT_EQ(C->getTrailingObjects<long>(),
             reinterpret_cast<long *>(llvm::alignAddr(
-                reinterpret_cast<char *>(C + 1) + 1, alignof(long))));
+                reinterpret_cast<char *>(C + 1) + 1, Align::Of<long>())));
 }
 }