Export of internal Abseil changes

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77cd6291781bc39e8472c706163d6951fe2ae573 by Derek Mauro <dmauro@google.com>:

absl::uint128: Use intrinsics for more operations when available

This change also inlines the division and modulus operators when
intrinsics are available for better code generation.

Fixes #987

PiperOrigin-RevId: 389895706

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fa23339584599e07ebcb4d0a857e2553b017757c by Abseil Team <absl-team@google.com>:

only hide retired flags if human-readable output is requested

PiperOrigin-RevId: 389835452

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f1111f2b88359d4b253d4d81681c8a488458a36e by Martijn Vels <mvels@google.com>:

Add helpers IsFlat(), IsExternal(), etc to improve readability

PiperOrigin-RevId: 389779333

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785b8712261e41695ebeeb64b4317f93b37adc11 by Martijn Vels <mvels@google.com>:

Split off 'concat' and 'btree' RepMemoryUsageLeaf and RepMemoryUsageDataEdge

PiperOrigin-RevId: 389701120

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5264bffebffc2b377bf7e18f0ce69a3ed38c6629 by CJ Johnson <johnsoncj@google.com>:

Eagerly destroy `Callback` in `absl::Cleanup`

PiperOrigin-RevId: 389678813

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a05312f0668458e97c50ca932c8f974c1508ebf2 by Abseil Team <absl-team@google.com>:

Have one instance of empty_group per program, rather than one per translation unit.

https://stackoverflow.com/questions/185624/static-variables-in-an-inlined-function

PiperOrigin-RevId: 389185845
GitOrigin-RevId: 77cd6291781bc39e8472c706163d6951fe2ae573
Change-Id: Iac8d9cb27707a9562c831c77a552d1fb4bb0405f

5 files changed, 34 insertions, 27 deletions

diff --git a/absl/strings/internal/cord_internal.h b/absl/strings/internal/cord_internal.h
index 8ae644ba..b7f3f4c0 100644
--- a/absl/strings/internal/cord_internal.h
+++ b/absl/strings/internal/cord_internal.h
@@ -216,6 +216,14 @@ struct CordRep {
   // padding space from the base class (clang and gcc do, MSVC does not, etc)
   uint8_t storage[3];
 
+  // Returns true if this instance's tag matches the requested type.
+  constexpr bool IsRing() const { return tag == RING; }
+  constexpr bool IsConcat() const { return tag == CONCAT; }
+  constexpr bool IsSubstring() const { return tag == SUBSTRING; }
+  constexpr bool IsExternal() const { return tag == EXTERNAL; }
+  constexpr bool IsFlat() const { return tag >= FLAT; }
+  constexpr bool IsBtree() const { return tag == BTREE; }
+
   inline CordRepRing* ring();
   inline const CordRepRing* ring() const;
   inline CordRepConcat* concat();
@@ -226,7 +234,6 @@ struct CordRep {
   inline const CordRepExternal* external() const;
   inline CordRepFlat* flat();
   inline const CordRepFlat* flat() const;
-
   inline CordRepBtree* btree();
   inline const CordRepBtree* btree() const;
 
@@ -277,7 +284,7 @@ struct CordRepExternal : public CordRep {
   ExternalReleaserInvoker releaser_invoker;
 
   // Deletes (releases) the external rep.
-  // Requires rep != nullptr and rep->tag == EXTERNAL
+  // Requires rep != nullptr and rep->IsExternal()
   static void Delete(CordRep* rep);
 };
 
@@ -320,7 +327,7 @@ struct CordRepExternalImpl
 };
 
 inline void CordRepExternal::Delete(CordRep* rep) {
-  assert(rep != nullptr && rep->tag == EXTERNAL);
+  assert(rep != nullptr && rep->IsExternal());
   auto* rep_external = static_cast<CordRepExternal*>(rep);
   assert(rep_external->releaser_invoker != nullptr);
   rep_external->releaser_invoker(rep_external);
@@ -531,32 +538,32 @@ class InlineData {
 static_assert(sizeof(InlineData) == kMaxInline + 1, "");
 
 inline CordRepConcat* CordRep::concat() {
-  assert(tag == CONCAT);
+  assert(IsConcat());
   return static_cast<CordRepConcat*>(this);
 }
 
 inline const CordRepConcat* CordRep::concat() const {
-  assert(tag == CONCAT);
+  assert(IsConcat());
   return static_cast<const CordRepConcat*>(this);
 }
 
 inline CordRepSubstring* CordRep::substring() {
-  assert(tag == SUBSTRING);
+  assert(IsSubstring());
   return static_cast<CordRepSubstring*>(this);
 }
 
 inline const CordRepSubstring* CordRep::substring() const {
-  assert(tag == SUBSTRING);
+  assert(IsSubstring());
   return static_cast<const CordRepSubstring*>(this);
 }
 
 inline CordRepExternal* CordRep::external() {
-  assert(tag == EXTERNAL);
+  assert(IsExternal());
   return static_cast<CordRepExternal*>(this);
 }
 
 inline const CordRepExternal* CordRep::external() const {
-  assert(tag == EXTERNAL);
+  assert(IsExternal());
   return static_cast<const CordRepExternal*>(this);
 }
 
diff --git a/absl/strings/internal/cord_rep_btree.cc b/absl/strings/internal/cord_rep_btree.cc
index fd3a0045..8fe589fa 100644
--- a/absl/strings/internal/cord_rep_btree.cc
+++ b/absl/strings/internal/cord_rep_btree.cc
@@ -79,7 +79,7 @@ void DumpAll(const CordRep* rep, bool include_contents, std::ostream& stream,
   // indented by two spaces per recursive depth.
   stream << std::string(depth * 2, ' ') << sharing << " (" << sptr << ") ";
 
-  if (rep->tag == BTREE) {
+  if (rep->IsBtree()) {
     const CordRepBtree* node = rep->btree();
     std::string label =
         node->height() ? absl::StrCat("Node(", node->height(), ")") : "Leaf";
@@ -378,7 +378,7 @@ bool CordRepBtree::IsValid(const CordRepBtree* tree, bool shallow) {
   }
 
   NODE_CHECK_VALID(tree != nullptr);
-  NODE_CHECK_EQ(tree->tag, BTREE);
+  NODE_CHECK_VALID(tree->IsBtree());
   NODE_CHECK_VALID(tree->height() <= kMaxHeight);
   NODE_CHECK_VALID(tree->begin() < tree->capacity());
   NODE_CHECK_VALID(tree->end() <= tree->capacity());
@@ -387,7 +387,7 @@ bool CordRepBtree::IsValid(const CordRepBtree* tree, bool shallow) {
   for (CordRep* edge : tree->Edges()) {
     NODE_CHECK_VALID(edge != nullptr);
     if (tree->height() > 0) {
-      NODE_CHECK_VALID(edge->tag == BTREE);
+      NODE_CHECK_VALID(edge->IsBtree());
       NODE_CHECK_VALID(edge->btree()->height() == tree->height() - 1);
     } else {
       NODE_CHECK_VALID(IsDataEdge(edge));
@@ -889,7 +889,7 @@ Span<char> CordRepBtree::GetAppendBufferSlow(size_t size) {
 }
 
 CordRepBtree* CordRepBtree::CreateSlow(CordRep* rep) {
-  if (rep->tag == BTREE) return rep->btree();
+  if (rep->IsBtree()) return rep->btree();
 
   CordRepBtree* node = nullptr;
   auto consume = [&node](CordRep* r, size_t offset, size_t length) {
@@ -905,7 +905,7 @@ CordRepBtree* CordRepBtree::CreateSlow(CordRep* rep) {
 }
 
 CordRepBtree* CordRepBtree::AppendSlow(CordRepBtree* tree, CordRep* rep) {
-  if (ABSL_PREDICT_TRUE(rep->tag == BTREE)) {
+  if (ABSL_PREDICT_TRUE(rep->IsBtree())) {
     return MergeTrees(tree, rep->btree());
   }
   auto consume = [&tree](CordRep* r, size_t offset, size_t length) {
@@ -917,7 +917,7 @@ CordRepBtree* CordRepBtree::AppendSlow(CordRepBtree* tree, CordRep* rep) {
 }
 
 CordRepBtree* CordRepBtree::PrependSlow(CordRepBtree* tree, CordRep* rep) {
-  if (ABSL_PREDICT_TRUE(rep->tag == BTREE)) {
+  if (ABSL_PREDICT_TRUE(rep->IsBtree())) {
     return MergeTrees(rep->btree(), tree);
   }
   auto consume = [&tree](CordRep* r, size_t offset, size_t length) {
diff --git a/absl/strings/internal/cord_rep_btree.h b/absl/strings/internal/cord_rep_btree.h
index 56e1e4af..8f000cab 100644
--- a/absl/strings/internal/cord_rep_btree.h
+++ b/absl/strings/internal/cord_rep_btree.h
@@ -153,7 +153,7 @@ class CordRepBtree : public CordRep {
   };
 
   // Creates a btree from the given input. Adopts a ref of `rep`.
-  // If the input `rep` is itself a btree, i.e., `tag == BTREE`, then this
+  // If the input `rep` is itself a btree, i.e., `IsBtree()`, then this
   // function immediately returns `rep->btree()`. If the input is a valid data
   // edge (see IsDataEdge()), then a new leaf node is returned containing `rep`
   // as the sole data edge. Else, the input is assumed to be a (legacy) concat
@@ -514,12 +514,12 @@ class CordRepBtree : public CordRep {
 };
 
 inline CordRepBtree* CordRep::btree() {
-  assert(tag == BTREE);
+  assert(IsBtree());
   return static_cast<CordRepBtree*>(this);
 }
 
 inline const CordRepBtree* CordRep::btree() const {
-  assert(tag == BTREE);
+  assert(IsBtree());
   return static_cast<const CordRepBtree*>(this);
 }
 
@@ -589,7 +589,7 @@ inline CordRepBtree* CordRepBtree::New(int height) {
 
 inline CordRepBtree* CordRepBtree::New(CordRep* rep) {
   CordRepBtree* tree = new CordRepBtree;
-  int height = rep->tag == BTREE ? rep->btree()->height() + 1 : 0;
+  int height = rep->IsBtree() ? rep->btree()->height() + 1 : 0;
   tree->length = rep->length;
   tree->InitInstance(height, /*begin=*/0, /*end=*/1);
   tree->edges_[0] = rep;
diff --git a/absl/strings/internal/cord_rep_ring.cc b/absl/strings/internal/cord_rep_ring.cc
index 20a6fc2b..db1f63fa 100644
--- a/absl/strings/internal/cord_rep_ring.cc
+++ b/absl/strings/internal/cord_rep_ring.cc
@@ -40,7 +40,7 @@ using index_type = CordRepRing::index_type;
 enum class Direction { kForward, kReversed };
 
 inline bool IsFlatOrExternal(CordRep* rep) {
-  return rep->tag >= FLAT || rep->tag == EXTERNAL;
+  return rep->IsFlat() || rep->IsExternal();
 }
 
 // Verifies that n + extra <= kMaxCapacity: throws std::length_error otherwise.
@@ -229,7 +229,7 @@ void CordRepRing::SetCapacityForTesting(size_t capacity) {
 }
 
 void CordRepRing::Delete(CordRepRing* rep) {
-  assert(rep != nullptr && rep->tag == RING);
+  assert(rep != nullptr && rep->IsRing());
 #if defined(__cpp_sized_deallocation)
   size_t size = AllocSize(rep->capacity_);
   rep->~CordRepRing();
@@ -360,7 +360,7 @@ CordRepRing* CordRepRing::Create(CordRep* child, size_t extra) {
   if (IsFlatOrExternal(child)) {
     return CreateFromLeaf(child, 0, length, extra);
   }
-  if (child->tag == RING) {
+  if (child->IsRing()) {
     return Mutable(child->ring(), extra);
   }
   return CreateSlow(child, extra);
@@ -433,7 +433,7 @@ CordRepRing* CordRepRing::AddRing(CordRepRing* rep, CordRepRing* ring,
 
 CordRepRing* CordRepRing::AppendSlow(CordRepRing* rep, CordRep* child) {
   Consume(child, [&rep](CordRep* child_arg, size_t offset, size_t len) {
-    if (child_arg->tag == RING) {
+    if (child_arg->IsRing()) {
       rep = AddRing<AddMode::kAppend>(rep, child_arg->ring(), offset, len);
     } else {
       rep = AppendLeaf(rep, child_arg, offset, len);
@@ -460,7 +460,7 @@ CordRepRing* CordRepRing::Append(CordRepRing* rep, CordRep* child) {
   if (IsFlatOrExternal(child)) {
     return AppendLeaf(rep, child, 0, length);
   }
-  if (child->tag == RING) {
+  if (child->IsRing()) {
     return AddRing<AddMode::kAppend>(rep, child->ring(), 0, length);
   }
   return AppendSlow(rep, child);
@@ -496,7 +496,7 @@ CordRepRing* CordRepRing::Prepend(CordRepRing* rep, CordRep* child) {
   if (IsFlatOrExternal(child)) {
     return PrependLeaf(rep, child, 0, length);
   }
-  if (child->tag == RING) {
+  if (child->IsRing()) {
     return AddRing<AddMode::kPrepend>(rep, child->ring(), 0, length);
   }
   return PrependSlow(rep, child);
diff --git a/absl/strings/internal/cord_rep_ring.h b/absl/strings/internal/cord_rep_ring.h
index 2082a565..44db8494 100644
--- a/absl/strings/internal/cord_rep_ring.h
+++ b/absl/strings/internal/cord_rep_ring.h
@@ -570,12 +570,12 @@ inline CordRepRing::Position CordRepRing::FindTail(index_type head,
 
 // Now that CordRepRing is defined, we can define CordRep's helper casts:
 inline CordRepRing* CordRep::ring() {
-  assert(tag == RING);
+  assert(IsRing());
   return static_cast<CordRepRing*>(this);
 }
 
 inline const CordRepRing* CordRep::ring() const {
-  assert(tag == RING);
+  assert(IsRing());
   return static_cast<const CordRepRing*>(this);
 }