Enhance synchscope representation

  OpenCL 2.0 introduces the notion of memory scopes in atomic operations to
  global and local memory. These scopes restrict how synchronization is
  achieved, which can result in improved performance.

  This change extends existing notion of synchronization scopes in LLVM to
  support arbitrary scopes expressed as target-specific strings, in addition to
  the already defined scopes (single thread, system).

  The LLVM IR and MIR syntax for expressing synchronization scopes has changed
  to use *syncscope("<scope>")*, where <scope> can be "singlethread" (this
  replaces *singlethread* keyword), or a target-specific name. As before, if
  the scope is not specified, it defaults to CrossThread/System scope.

  Implementation details:
    - Mapping from synchronization scope name/string to synchronization scope id
      is stored in LLVM context;
    - CrossThread/System and SingleThread scopes are pre-defined to efficiently
      check for known scopes without comparing strings;
    - Synchronization scope names are stored in SYNC_SCOPE_NAMES_BLOCK in
      the bitcode.

Differential Revision: https://reviews.llvm.org/D21723

llvm-svn: 307722

4 files changed, 47 insertions, 24 deletions

diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index a49276099f1..428bb21fbf5 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -542,7 +542,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   KEYWORD(release);
   KEYWORD(acq_rel);
   KEYWORD(seq_cst);
-  KEYWORD(singlethread);
+  KEYWORD(syncscope);
 
   KEYWORD(nnan);
   KEYWORD(ninf);
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 7817449dac7..717eb0e00f4 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -1919,20 +1919,42 @@ bool LLParser::parseAllocSizeArguments(unsigned &BaseSizeArg,
 }
 
 /// ParseScopeAndOrdering
-///   if isAtomic: ::= 'singlethread'? AtomicOrdering
+///   if isAtomic: ::= SyncScope? AtomicOrdering
 ///   else: ::=
 ///
 /// This sets Scope and Ordering to the parsed values.
-bool LLParser::ParseScopeAndOrdering(bool isAtomic, SynchronizationScope &Scope,
+bool LLParser::ParseScopeAndOrdering(bool isAtomic, SyncScope::ID &SSID,
                                      AtomicOrdering &Ordering) {
   if (!isAtomic)
     return false;
 
-  Scope = CrossThread;
-  if (EatIfPresent(lltok::kw_singlethread))
-    Scope = SingleThread;
+  return ParseScope(SSID) || ParseOrdering(Ordering);
+}
+
+/// ParseScope
+///   ::= syncscope("singlethread" | "<target scope>")?
+///
+/// This sets synchronization scope ID to the ID of the parsed value.
+bool LLParser::ParseScope(SyncScope::ID &SSID) {
+  SSID = SyncScope::System;
+  if (EatIfPresent(lltok::kw_syncscope)) {
+    auto StartParenAt = Lex.getLoc();
+    if (!EatIfPresent(lltok::lparen))
+      return Error(StartParenAt, "Expected '(' in syncscope");
+
+    std::string SSN;
+    auto SSNAt = Lex.getLoc();
+    if (ParseStringConstant(SSN))
+      return Error(SSNAt, "Expected synchronization scope name");
 
-  return ParseOrdering(Ordering);
+    auto EndParenAt = Lex.getLoc();
+    if (!EatIfPresent(lltok::rparen))
+      return Error(EndParenAt, "Expected ')' in syncscope");
+
+    SSID = Context.getOrInsertSyncScopeID(SSN);
+  }
+
+  return false;
 }
 
 /// ParseOrdering
@@ -6100,7 +6122,7 @@ int LLParser::ParseLoad(Instruction *&Inst, PerFunctionState &PFS) {
   bool AteExtraComma = false;
   bool isAtomic = false;
   AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
-  SynchronizationScope Scope = CrossThread;
+  SyncScope::ID SSID = SyncScope::System;
 
   if (Lex.getKind() == lltok::kw_atomic) {
     isAtomic = true;
@@ -6118,7 +6140,7 @@ int LLParser::ParseLoad(Instruction *&Inst, PerFunctionState &PFS) {
   if (ParseType(Ty) ||
       ParseToken(lltok::comma, "expected comma after load's type") ||
       ParseTypeAndValue(Val, Loc, PFS) ||
-      ParseScopeAndOrdering(isAtomic, Scope, Ordering) ||
+      ParseScopeAndOrdering(isAtomic, SSID, Ordering) ||
       ParseOptionalCommaAlign(Alignment, AteExtraComma))
     return true;
 
@@ -6134,7 +6156,7 @@ int LLParser::ParseLoad(Instruction *&Inst, PerFunctionState &PFS) {
     return Error(ExplicitTypeLoc,
                  "explicit pointee type doesn't match operand's pointee type");
 
-  Inst = new LoadInst(Ty, Val, "", isVolatile, Alignment, Ordering, Scope);
+  Inst = new LoadInst(Ty, Val, "", isVolatile, Alignment, Ordering, SSID);
   return AteExtraComma ? InstExtraComma : InstNormal;
 }
 
@@ -6149,7 +6171,7 @@ int LLParser::ParseStore(Instruction *&Inst, PerFunctionState &PFS) {
   bool AteExtraComma = false;
   bool isAtomic = false;
   AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
-  SynchronizationScope Scope = CrossThread;
+  SyncScope::ID SSID = SyncScope::System;
 
   if (Lex.getKind() == lltok::kw_atomic) {
     isAtomic = true;
@@ -6165,7 +6187,7 @@ int LLParser::ParseStore(Instruction *&Inst, PerFunctionState &PFS) {
   if (ParseTypeAndValue(Val, Loc, PFS) ||
       ParseToken(lltok::comma, "expected ',' after store operand") ||
       ParseTypeAndValue(Ptr, PtrLoc, PFS) ||
-      ParseScopeAndOrdering(isAtomic, Scope, Ordering) ||
+      ParseScopeAndOrdering(isAtomic, SSID, Ordering) ||
       ParseOptionalCommaAlign(Alignment, AteExtraComma))
     return true;
 
@@ -6181,7 +6203,7 @@ int LLParser::ParseStore(Instruction *&Inst, PerFunctionState &PFS) {
       Ordering == AtomicOrdering::AcquireRelease)
     return Error(Loc, "atomic store cannot use Acquire ordering");
 
-  Inst = new StoreInst(Val, Ptr, isVolatile, Alignment, Ordering, Scope);
+  Inst = new StoreInst(Val, Ptr, isVolatile, Alignment, Ordering, SSID);
   return AteExtraComma ? InstExtraComma : InstNormal;
 }
 
@@ -6193,7 +6215,7 @@ int LLParser::ParseCmpXchg(Instruction *&Inst, PerFunctionState &PFS) {
   bool AteExtraComma = false;
   AtomicOrdering SuccessOrdering = AtomicOrdering::NotAtomic;
   AtomicOrdering FailureOrdering = AtomicOrdering::NotAtomic;
-  SynchronizationScope Scope = CrossThread;
+  SyncScope::ID SSID = SyncScope::System;
   bool isVolatile = false;
   bool isWeak = false;
 
@@ -6208,7 +6230,7 @@ int LLParser::ParseCmpXchg(Instruction *&Inst, PerFunctionState &PFS) {
       ParseTypeAndValue(Cmp, CmpLoc, PFS) ||
       ParseToken(lltok::comma, "expected ',' after cmpxchg cmp operand") ||
       ParseTypeAndValue(New, NewLoc, PFS) ||
-      ParseScopeAndOrdering(true /*Always atomic*/, Scope, SuccessOrdering) ||
+      ParseScopeAndOrdering(true /*Always atomic*/, SSID, SuccessOrdering) ||
       ParseOrdering(FailureOrdering))
     return true;
 
@@ -6231,7 +6253,7 @@ int LLParser::ParseCmpXchg(Instruction *&Inst, PerFunctionState &PFS) {
   if (!New->getType()->isFirstClassType())
     return Error(NewLoc, "cmpxchg operand must be a first class value");
   AtomicCmpXchgInst *CXI = new AtomicCmpXchgInst(
-      Ptr, Cmp, New, SuccessOrdering, FailureOrdering, Scope);
+      Ptr, Cmp, New, SuccessOrdering, FailureOrdering, SSID);
   CXI->setVolatile(isVolatile);
   CXI->setWeak(isWeak);
   Inst = CXI;
@@ -6245,7 +6267,7 @@ int LLParser::ParseAtomicRMW(Instruction *&Inst, PerFunctionState &PFS) {
   Value *Ptr, *Val; LocTy PtrLoc, ValLoc;
   bool AteExtraComma = false;
   AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
-  SynchronizationScope Scope = CrossThread;
+  SyncScope::ID SSID = SyncScope::System;
   bool isVolatile = false;
   AtomicRMWInst::BinOp Operation;
 
@@ -6271,7 +6293,7 @@ int LLParser::ParseAtomicRMW(Instruction *&Inst, PerFunctionState &PFS) {
   if (ParseTypeAndValue(Ptr, PtrLoc, PFS) ||
       ParseToken(lltok::comma, "expected ',' after atomicrmw address") ||
       ParseTypeAndValue(Val, ValLoc, PFS) ||
-      ParseScopeAndOrdering(true /*Always atomic*/, Scope, Ordering))
+      ParseScopeAndOrdering(true /*Always atomic*/, SSID, Ordering))
     return true;
 
   if (Ordering == AtomicOrdering::Unordered)
@@ -6288,7 +6310,7 @@ int LLParser::ParseAtomicRMW(Instruction *&Inst, PerFunctionState &PFS) {
                          " integer");
 
   AtomicRMWInst *RMWI =
-    new AtomicRMWInst(Operation, Ptr, Val, Ordering, Scope);
+    new AtomicRMWInst(Operation, Ptr, Val, Ordering, SSID);
   RMWI->setVolatile(isVolatile);
   Inst = RMWI;
   return AteExtraComma ? InstExtraComma : InstNormal;
@@ -6298,8 +6320,8 @@ int LLParser::ParseAtomicRMW(Instruction *&Inst, PerFunctionState &PFS) {
 ///   ::= 'fence' 'singlethread'? AtomicOrdering
 int LLParser::ParseFence(Instruction *&Inst, PerFunctionState &PFS) {
   AtomicOrdering Ordering = AtomicOrdering::NotAtomic;
-  SynchronizationScope Scope = CrossThread;
-  if (ParseScopeAndOrdering(true /*Always atomic*/, Scope, Ordering))
+  SyncScope::ID SSID = SyncScope::System;
+  if (ParseScopeAndOrdering(true /*Always atomic*/, SSID, Ordering))
     return true;
 
   if (Ordering == AtomicOrdering::Unordered)
@@ -6307,7 +6329,7 @@ int LLParser::ParseFence(Instruction *&Inst, PerFunctionState &PFS) {
   if (Ordering == AtomicOrdering::Monotonic)
     return TokError("fence cannot be monotonic");
 
-  Inst = new FenceInst(Context, Ordering, Scope);
+  Inst = new FenceInst(Context, Ordering, SSID);
   return InstNormal;
 }
 
diff --git a/llvm/lib/AsmParser/LLParser.h b/llvm/lib/AsmParser/LLParser.h
index 4616c2e8694..d5b059355c4 100644
--- a/llvm/lib/AsmParser/LLParser.h
+++ b/llvm/lib/AsmParser/LLParser.h
@@ -241,8 +241,9 @@ namespace llvm {
     bool ParseOptionalCallingConv(unsigned &CC);
     bool ParseOptionalAlignment(unsigned &Alignment);
     bool ParseOptionalDerefAttrBytes(lltok::Kind AttrKind, uint64_t &Bytes);
-    bool ParseScopeAndOrdering(bool isAtomic, SynchronizationScope &Scope,
+    bool ParseScopeAndOrdering(bool isAtomic, SyncScope::ID &SSID,
                                AtomicOrdering &Ordering);
+    bool ParseScope(SyncScope::ID &SSID);
     bool ParseOrdering(AtomicOrdering &Ordering);
     bool ParseOptionalStackAlignment(unsigned &Alignment);
     bool ParseOptionalCommaAlign(unsigned &Alignment, bool &AteExtraComma);
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index 6c8ed7da495..9c7a06de81b 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -93,7 +93,7 @@ enum Kind {
   kw_release,
   kw_acq_rel,
   kw_seq_cst,
-  kw_singlethread,
+  kw_syncscope,
   kw_nnan,
   kw_ninf,
   kw_nsz,