Reimplement the parameter attributes support, phase #1. hilights:

1. There is now a "PAListPtr" class, which is a smart pointer around
   the underlying uniqued parameter attribute list object, and manages
   its refcount.  It is now impossible to mess up the refcount.
2. PAListPtr is now the main interface to the underlying object, and
   the underlying object is now completely opaque.
3. Implementation details like SmallVector and FoldingSet are now no
   longer part of the interface.
4. You can create a PAListPtr with an arbitrary sequence of
   ParamAttrsWithIndex's, no need to make a SmallVector of a specific 
   size (you can just use an array or scalar or vector if you wish).
5. All the client code that had to check for a null pointer before
   dereferencing the pointer is simplified to just access the 
   PAListPtr directly.
6. The interfaces for adding attrs to a list and removing them is a
   bit simpler.

Phase #2 will rename some stuff (e.g. PAListPtr) and do other less 
invasive changes.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48289 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 28 insertions, 38 deletions

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index c86ee3048a..e948329fe8 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -18,7 +18,6 @@
 #include "llvm/InlineAsm.h"
 #include "llvm/Instructions.h"
 #include "llvm/Module.h"
-#include "llvm/ParamAttrsList.h"
 #include "llvm/AutoUpgrade.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
@@ -32,11 +31,7 @@ void BitcodeReader::FreeState() {
   std::vector<PATypeHolder>().swap(TypeList);
   ValueList.clear();
   
-  // Drop references to ParamAttrs.
-  for (unsigned i = 0, e = ParamAttrs.size(); i != e; ++i)
-    ParamAttrs[i]->dropRef();
-  
-  std::vector<const ParamAttrsList*>().swap(ParamAttrs);
+  std::vector<PAListPtr>().swap(ParamAttrs);
   std::vector<BasicBlock*>().swap(FunctionBBs);
   std::vector<Function*>().swap(FunctionsWithBodies);
   DeferredFunctionInfo.clear();
@@ -205,7 +200,7 @@ bool BitcodeReader::ParseParamAttrBlock() {
   
   SmallVector<uint64_t, 64> Record;
   
-  ParamAttrsVector Attrs;
+  SmallVector<ParamAttrsWithIndex, 8> Attrs;
   
   // Read all the records.
   while (1) {
@@ -242,13 +237,8 @@ bool BitcodeReader::ParseParamAttrBlock() {
         if (Record[i+1] != ParamAttr::None)
           Attrs.push_back(ParamAttrsWithIndex::get(Record[i], Record[i+1]));
       }
-      if (Attrs.empty()) {
-        ParamAttrs.push_back(0);
-      } else {
-        ParamAttrs.push_back(ParamAttrsList::get(Attrs));
-        ParamAttrs.back()->addRef();
-      }
 
+      ParamAttrs.push_back(PAListPtr::get(Attrs.begin(), Attrs.end()));
       Attrs.clear();
       break;
     }
@@ -1062,8 +1052,7 @@ bool BitcodeReader::ParseModule(const std::string &ModuleID) {
       Func->setCallingConv(Record[1]);
       bool isProto = Record[2];
       Func->setLinkage(GetDecodedLinkage(Record[3]));
-      const ParamAttrsList *PAL = getParamAttrs(Record[4]);
-      Func->setParamAttrs(PAL);
+      Func->setParamAttrs(getParamAttrs(Record[4]));
       
       Func->setAlignment((1 << Record[5]) >> 1);
       if (Record[6]) {
@@ -1427,7 +1416,7 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
     case bitc::FUNC_CODE_INST_INVOKE: {
       // INVOKE: [attrs, cc, normBB, unwindBB, fnty, op0,op1,op2, ...]
       if (Record.size() < 4) return Error("Invalid INVOKE record");
-      const ParamAttrsList *PAL = getParamAttrs(Record[0]);
+      PAListPtr PAL = getParamAttrs(Record[0]);
       unsigned CCInfo = Record[1];
       BasicBlock *NormalBB = getBasicBlock(Record[2]);
       BasicBlock *UnwindBB = getBasicBlock(Record[3]);
@@ -1565,7 +1554,7 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
       if (Record.size() < 3)
         return Error("Invalid CALL record");
       
-      const ParamAttrsList *PAL = getParamAttrs(Record[0]);
+      PAListPtr PAL = getParamAttrs(Record[0]);
       unsigned CCInfo = Record[1];
       
       unsigned OpNum = 2;
diff --git a/lib/Bitcode/Reader/BitcodeReader.h b/lib/Bitcode/Reader/BitcodeReader.h
index d7df1a1b02..9a140d9524 100644
--- a/lib/Bitcode/Reader/BitcodeReader.h
+++ b/lib/Bitcode/Reader/BitcodeReader.h
@@ -15,6 +15,7 @@
 #define BITCODE_READER_H
 
 #include "llvm/ModuleProvider.h"
+#include "llvm/ParameterAttributes.h"
 #include "llvm/Type.h"
 #include "llvm/User.h"
 #include "llvm/Bitcode/BitstreamReader.h"
@@ -24,7 +25,6 @@
 
 namespace llvm {
   class MemoryBuffer;
-  class ParamAttrsList;
   
 class BitcodeReaderValueList : public User {
   std::vector<Use> Uses;
@@ -93,7 +93,7 @@ class BitcodeReader : public ModuleProvider {
   /// ParamAttrs - The set of parameter attributes by index.  Index zero in the
   /// file is for null, and is thus not represented here.  As such all indices
   /// are off by one.
-  std::vector<const ParamAttrsList*> ParamAttrs;
+  std::vector<PAListPtr> ParamAttrs;
   
   /// FunctionBBs - While parsing a function body, this is a list of the basic
   /// blocks for the function.
@@ -156,10 +156,10 @@ private:
     if (ID >= FunctionBBs.size()) return 0; // Invalid ID
     return FunctionBBs[ID];
   }
-  const ParamAttrsList *getParamAttrs(unsigned i) const {
+  PAListPtr getParamAttrs(unsigned i) const {
     if (i-1 < ParamAttrs.size())
       return ParamAttrs[i-1];
-    return 0;
+    return PAListPtr();
   }
   
   /// getValueTypePair - Read a value/type pair out of the specified record from
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index aaad22688a..96f045cd47 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -20,7 +20,6 @@
 #include "llvm/InlineAsm.h"
 #include "llvm/Instructions.h"
 #include "llvm/Module.h"
-#include "llvm/ParamAttrsList.h"
 #include "llvm/TypeSymbolTable.h"
 #include "llvm/ValueSymbolTable.h"
 #include "llvm/Support/MathExtras.h"
@@ -109,17 +108,18 @@ static void WriteStringRecord(unsigned Code, const std::string &Str,
 // Emit information about parameter attributes.
 static void WriteParamAttrTable(const ValueEnumerator &VE, 
                                 BitstreamWriter &Stream) {
-  const std::vector<const ParamAttrsList*> &Attrs = VE.getParamAttrs();
+  const std::vector<PAListPtr> &Attrs = VE.getParamAttrs();
   if (Attrs.empty()) return;
   
   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
-    const ParamAttrsList *A = Attrs[i];
-    for (unsigned op = 0, e = A->size(); op != e; ++op) {
-      Record.push_back(A->getParamIndex(op));
-      Record.push_back(A->getParamAttrsAtIndex(op));
+    const PAListPtr &A = Attrs[i];
+    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
+      const ParamAttrsWithIndex &PAWI = A.getSlot(i);
+      Record.push_back(PAWI.Index);
+      Record.push_back(PAWI.Attrs);
     }
     
     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
diff --git a/lib/Bitcode/Writer/ValueEnumerator.cpp b/lib/Bitcode/Writer/ValueEnumerator.cpp
index d2efe078c0..09a1db3d62 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -245,10 +245,10 @@ void ValueEnumerator::EnumerateOperandType(const Value *V) {
   }
 }
 
-void ValueEnumerator::EnumerateParamAttrs(const ParamAttrsList *PAL) {
-  if (PAL == 0) return;  // null is always 0.
+void ValueEnumerator::EnumerateParamAttrs(const PAListPtr &PAL) {
+  if (PAL.isEmpty()) return;  // null is always 0.
   // Do a lookup.
-  unsigned &Entry = ParamAttrMap[PAL];
+  unsigned &Entry = ParamAttrMap[PAL.getRawPointer()];
   if (Entry == 0) {
     // Never saw this before, add it.
     ParamAttrs.push_back(PAL);
diff --git a/lib/Bitcode/Writer/ValueEnumerator.h b/lib/Bitcode/Writer/ValueEnumerator.h
index 9fb916a515..dc40d016dc 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.h
+++ b/lib/Bitcode/Writer/ValueEnumerator.h
@@ -15,6 +15,7 @@
 #define VALUE_ENUMERATOR_H
 
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ParameterAttributes.h"
 #include <vector>
 
 namespace llvm {
@@ -24,7 +25,7 @@ class Value;
 class BasicBlock;
 class Function;
 class Module;
-class ParamAttrsList;
+class PAListPtr;
 class TypeSymbolTable;
 class ValueSymbolTable;
 
@@ -44,9 +45,9 @@ private:
   ValueMapType ValueMap;
   ValueList Values;
   
-  typedef DenseMap<const ParamAttrsList*, unsigned> ParamAttrMapType;
+  typedef DenseMap<void*, unsigned> ParamAttrMapType;
   ParamAttrMapType ParamAttrMap;
-  std::vector<const ParamAttrsList*> ParamAttrs;
+  std::vector<PAListPtr> ParamAttrs;
   
   /// BasicBlocks - This contains all the basic blocks for the currently
   /// incorporated function.  Their reverse mapping is stored in ValueMap.
@@ -75,9 +76,9 @@ public:
     return I->second-1;
   }
   
-  unsigned getParamAttrID(const ParamAttrsList *PAL) const {
-    if (PAL == 0) return 0;  // Null maps to zero.
-    ParamAttrMapType::const_iterator I = ParamAttrMap.find(PAL);
+  unsigned getParamAttrID(const PAListPtr &PAL) const {
+    if (PAL.isEmpty()) return 0;  // Null maps to zero.
+    ParamAttrMapType::const_iterator I = ParamAttrMap.find(PAL.getRawPointer());
     assert(I != ParamAttrMap.end() && "ParamAttr not in ValueEnumerator!");
     return I->second;
   }
@@ -94,7 +95,7 @@ public:
   const std::vector<const BasicBlock*> &getBasicBlocks() const {
     return BasicBlocks; 
   }
-  const std::vector<const ParamAttrsList*> &getParamAttrs() const {
+  const std::vector<PAListPtr> &getParamAttrs() const {
     return ParamAttrs;
   }
 
@@ -115,7 +116,7 @@ private:
   void EnumerateValue(const Value *V);
   void EnumerateType(const Type *T);
   void EnumerateOperandType(const Value *V);
-  void EnumerateParamAttrs(const ParamAttrsList *PAL);
+  void EnumerateParamAttrs(const PAListPtr &PAL);
   
   void EnumerateTypeSymbolTable(const TypeSymbolTable &ST);
   void EnumerateValueSymbolTable(const ValueSymbolTable &ST);