Implement function prefix data as an IR feature.

Previous discussion:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-July/063909.html

Differential Revision: http://llvm-reviews.chandlerc.com/D1191

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190773 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 29 insertions, 1 deletions

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index ca432fd..0c20163 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1106,9 +1106,11 @@ uint64_t BitcodeReader::decodeSignRotatedValue(uint64_t V) {
 bool BitcodeReader::ResolveGlobalAndAliasInits() {
   std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitWorklist;
   std::vector<std::pair<GlobalAlias*, unsigned> > AliasInitWorklist;
+  std::vector<std::pair<Function*, unsigned> > FunctionPrefixWorklist;
 
   GlobalInitWorklist.swap(GlobalInits);
   AliasInitWorklist.swap(AliasInits);
+  FunctionPrefixWorklist.swap(FunctionPrefixes);
 
   while (!GlobalInitWorklist.empty()) {
     unsigned ValID = GlobalInitWorklist.back().second;
@@ -1136,6 +1138,20 @@ bool BitcodeReader::ResolveGlobalAndAliasInits() {
     }
     AliasInitWorklist.pop_back();
   }
+
+  while (!FunctionPrefixWorklist.empty()) {
+    unsigned ValID = FunctionPrefixWorklist.back().second;
+    if (ValID >= ValueList.size()) {
+      FunctionPrefixes.push_back(FunctionPrefixWorklist.back());
+    } else {
+      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
+        FunctionPrefixWorklist.back().first->setPrefixData(C);
+      else
+        return Error("Function prefix is not a constant!");
+    }
+    FunctionPrefixWorklist.pop_back();
+  }
+
   return false;
 }
 
@@ -1881,6 +1897,8 @@ bool BitcodeReader::ParseModule(bool Resume) {
       if (Record.size() > 9)
         UnnamedAddr = Record[9];
       Func->setUnnamedAddr(UnnamedAddr);
+      if (Record.size() > 10 && Record[10] != 0)
+        FunctionPrefixes.push_back(std::make_pair(Func, Record[10]-1));
       ValueList.push_back(Func);
 
       // If this is a function with a body, remember the prototype we are
diff --git a/lib/Bitcode/Reader/BitcodeReader.h b/lib/Bitcode/Reader/BitcodeReader.h
index b095447..9533597 100644
--- a/lib/Bitcode/Reader/BitcodeReader.h
+++ b/lib/Bitcode/Reader/BitcodeReader.h
@@ -142,6 +142,7 @@ class BitcodeReader : public GVMaterializer {
 
   std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInits;
   std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
+  std::vector<std::pair<Function*, unsigned> > FunctionPrefixes;
 
   /// MAttributes - The set of attributes by index.  Index zero in the
   /// file is for null, and is thus not represented here.  As such all indices
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index ed3c267..46eff4e 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -632,7 +632,7 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
   // Emit the function proto information.
   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
-    //             section, visibility, gc, unnamed_addr]
+    //             section, visibility, gc, unnamed_addr, prefix]
     Vals.push_back(VE.getTypeID(F->getType()));
     Vals.push_back(F->getCallingConv());
     Vals.push_back(F->isDeclaration());
@@ -643,6 +643,8 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
     Vals.push_back(getEncodedVisibility(F));
     Vals.push_back(F->hasGC() ? GCMap[F->getGC()] : 0);
     Vals.push_back(F->hasUnnamedAddr());
+    Vals.push_back(F->hasPrefixData() ? (VE.getValueID(F->getPrefixData()) + 1)
+                                      : 0);
 
     unsigned AbbrevToUse = 0;
     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
@@ -1863,6 +1865,8 @@ static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
     WriteUseList(FI, VE, Stream);
     if (!FI->isDeclaration())
       WriteFunctionUseList(FI, VE, Stream);
+    if (FI->hasPrefixData())
+      WriteUseList(FI->getPrefixData(), VE, Stream);
   }
 
   // Write the aliases.
diff --git a/lib/Bitcode/Writer/ValueEnumerator.cpp b/lib/Bitcode/Writer/ValueEnumerator.cpp
index 8bac6da..a164104 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -60,6 +60,11 @@ ValueEnumerator::ValueEnumerator(const Module *M) {
        I != E; ++I)
     EnumerateValue(I->getAliasee());
 
+  // Enumerate the prefix data constants.
+  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
+    if (I->hasPrefixData())
+      EnumerateValue(I->getPrefixData());
+
   // Insert constants and metadata that are named at module level into the slot
   // pool so that the module symbol table can refer to them...
   EnumerateValueSymbolTable(M->getValueSymbolTable());