Remove module info records not allowed by PNaCl from the bitcode.

Remove dead code for:

   (1) Top-level inline assembly.
   (2) Remove code for named sections.
   (3) Remove code for GC names.
   (4) Global variable aliases.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3405
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/18770005

3 files changed, 19 insertions, 174 deletions

diff --git a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
index 0b7506fad6..09a94c08cf 100644
--- a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
+++ b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Support/DataStream.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
 enum {
@@ -92,15 +93,6 @@ static GlobalValue::LinkageTypes GetDecodedLinkage(unsigned Val) {
   }
 }
 
-static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
-  switch (Val) {
-  default: // Map unknown visibilities to default.
-  case 0: return GlobalValue::DefaultVisibility;
-  case 1: return GlobalValue::HiddenVisibility;
-  case 2: return GlobalValue::ProtectedVisibility;
-  }
-}
-
 static int GetDecodedCastOpcode(unsigned Val) {
   switch (Val) {
   default: return -1;
@@ -868,27 +860,6 @@ bool NaClBitcodeReader::ParseValueSymbolTable() {
   }
 }
 
-/// ResolveAliasInits - Resolve all of the initializers for aliases that we can.
-bool NaClBitcodeReader::ResolveAliasInits() {
-  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInitWorklist;
-
-  AliasInitWorklist.swap(AliasInits);
-
-  while (!AliasInitWorklist.empty()) {
-    unsigned ValID = AliasInitWorklist.back().second;
-    if (ValID >= ValueList.size()) {
-      AliasInits.push_back(AliasInitWorklist.back());
-    } else {
-      if (Constant *C = dyn_cast<Constant>(ValueList[ValID]))
-        AliasInitWorklist.back().first->setAliasee(C);
-      else
-        return Error("Alias initializer is not a constant!");
-    }
-    AliasInitWorklist.pop_back();
-  }
-  return false;
-}
-
 static APInt ReadWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits) {
   SmallVector<uint64_t, 8> Words(Vals.size());
   std::transform(Vals.begin(), Vals.end(), Words.begin(),
@@ -1358,12 +1329,6 @@ bool NaClBitcodeReader::RememberAndSkipFunctionBody() {
 }
 
 bool NaClBitcodeReader::GlobalCleanup() {
-  // Patch the initializers for globals and aliases up.
-  ResolveAliasInits();
-
-  if (!AliasInits.empty())
-    return Error("Malformed Alias Initializer");
-
   // Look for intrinsic functions which need to be upgraded at some point
   for (Module::iterator FI = TheModule->begin(), FE = TheModule->end();
        FI != FE; ++FI) {
@@ -1377,7 +1342,6 @@ bool NaClBitcodeReader::GlobalCleanup() {
          GI = TheModule->global_begin(), GE = TheModule->global_end();
        GI != GE; ++GI)
     UpgradeGlobalVariable(GI);
-  std::vector<std::pair<GlobalAlias*, unsigned> >().swap(AliasInits);
   return false;
 }
 
@@ -1389,8 +1353,6 @@ bool NaClBitcodeReader::ParseModule(bool Resume) {
     return Error("Malformed block record");
 
   SmallVector<uint64_t, 64> Record;
-  std::vector<std::string> SectionTable;
-  std::vector<std::string> GCTable;
 
   // Read all the records for this module.
   while (1) {
@@ -1429,7 +1391,7 @@ bool NaClBitcodeReader::ParseModule(bool Resume) {
         SeenValueSymbolTable = true;
         break;
       case naclbitc::CONSTANTS_BLOCK_ID:
-        if (ParseConstants() || ResolveAliasInits())
+        if (ParseConstants())
           return true;
         break;
       case naclbitc::FUNCTION_BLOCK_ID:
@@ -1469,10 +1431,16 @@ bool NaClBitcodeReader::ParseModule(bool Resume) {
       break;
     }
 
-
     // Read a record.
-    switch (Stream.readRecord(Entry.ID, Record)) {
-    default: break;  // Default behavior, ignore unknown content.
+    unsigned Selector = Stream.readRecord(Entry.ID, Record);
+    switch (Selector) {
+    default: {
+      std::string Message;
+      raw_string_ostream StrM(Message);
+      StrM << "Invalid MODULE_CODE: " << Selector;
+      StrM.flush();
+      return Error(Message);
+    }
     case naclbitc::MODULE_CODE_VERSION: {  // VERSION: [version#]
       if (Record.size() < 1)
         return Error("Malformed MODULE_CODE_VERSION");
@@ -1489,40 +1457,6 @@ bool NaClBitcodeReader::ParseModule(bool Resume) {
       }
       break;
     }
-    case naclbitc::MODULE_CODE_ASM: {  // ASM: [strchr x N]
-      std::string S;
-      if (ConvertToString(Record, 0, S))
-        return Error("Invalid MODULE_CODE_ASM record");
-      TheModule->setModuleInlineAsm(S);
-      break;
-    }
-    case naclbitc::MODULE_CODE_DEPLIB: {  // DEPLIB: [strchr x N]
-      // FIXME: Remove in 4.0.
-      std::string S;
-      if (ConvertToString(Record, 0, S))
-        return Error("Invalid MODULE_CODE_DEPLIB record");
-      // Ignore value.
-      break;
-    }
-    case naclbitc::MODULE_CODE_SECTIONNAME: {  // SECTIONNAME: [strchr x N]
-      std::string S;
-      if (ConvertToString(Record, 0, S))
-        return Error("Invalid MODULE_CODE_SECTIONNAME record");
-      SectionTable.push_back(S);
-      break;
-    }
-    case naclbitc::MODULE_CODE_GCNAME: {  // SECTIONNAME: [strchr x N]
-      std::string S;
-      if (ConvertToString(Record, 0, S))
-        return Error("Invalid MODULE_CODE_GCNAME record");
-      GCTable.push_back(S);
-      break;
-    }
-    // GLOBALVAR: [pointer type, isconst, initid,
-    //             linkage, alignment, section, visibility, threadlocal,
-    //             unnamed_addr]
-    case naclbitc::MODULE_CODE_GLOBALVAR:
-      return Error("Invalid MODULE_CODE_GLOBALVAR record");
     // FUNCTION:  [type, callingconv, isproto, linkage]
     case naclbitc::MODULE_CODE_FUNCTION: {
       if (Record.size() < 4)
@@ -1552,32 +1486,6 @@ bool NaClBitcodeReader::ParseModule(bool Resume) {
       }
       break;
     }
-    // ALIAS: [alias type, aliasee val#, linkage]
-    // ALIAS: [alias type, aliasee val#, linkage, visibility]
-    case naclbitc::MODULE_CODE_ALIAS: {
-      if (Record.size() < 3)
-        return Error("Invalid MODULE_ALIAS record");
-      Type *Ty = getTypeByID(Record[0]);
-      if (!Ty) return Error("Invalid MODULE_ALIAS record");
-      if (!Ty->isPointerTy())
-        return Error("Function not a pointer type!");
-
-      GlobalAlias *NewGA = new GlobalAlias(Ty, GetDecodedLinkage(Record[2]),
-                                           "", 0, TheModule);
-      // Old bitcode files didn't have visibility field.
-      if (Record.size() > 3)
-        NewGA->setVisibility(GetDecodedVisibility(Record[3]));
-      ValueList.push_back(NewGA);
-      AliasInits.push_back(std::make_pair(NewGA, Record[1]));
-      break;
-    }
-    /// MODULE_CODE_PURGEVALS: [numvals]
-    case naclbitc::MODULE_CODE_PURGEVALS:
-      // Trim down the value list to the specified size.
-      if (Record.size() < 1 || Record[0] > ValueList.size())
-        return Error("Invalid MODULE_PURGEVALS record");
-      ValueList.shrinkTo(Record[0]);
-      break;
     }
     Record.clear();
   }
diff --git a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
index 4105eb53b8..3b9d8982d5 100644
--- a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
+++ b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
@@ -126,14 +126,12 @@ class NaClBitcodeReader : public GVMaterializer {
   uint64_t NextUnreadBit;
   bool SeenValueSymbolTable;
 
-  const char *ErrorString;
+  std::string ErrorString;
 
   std::vector<Type*> TypeList;
   NaClBitcodeReaderValueList ValueList;
   SmallVector<SmallVector<uint64_t, 64>, 64> UseListRecords;
 
-  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
-
   /// FunctionBBs - While parsing a function body, this is a list of the basic
   /// blocks for the function.
   std::vector<BasicBlock*> FunctionBBs;
@@ -179,7 +177,7 @@ public:
                              bool AcceptSupportedOnly = true)
     : Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
       LazyStreamer(0), NextUnreadBit(0), SeenValueSymbolTable(false),
-      ErrorString(0), ValueList(C),
+      ValueList(C),
       SeenFirstFunctionBody(false), UseRelativeIDs(false),
       AcceptSupportedBitcodeOnly(AcceptSupportedOnly) {
   }
@@ -187,7 +185,7 @@ public:
                              bool AcceptSupportedOnly = true)
     : Context(C), TheModule(0), Buffer(0), BufferOwned(false),
       LazyStreamer(streamer), NextUnreadBit(0), SeenValueSymbolTable(false),
-      ErrorString(0), ValueList(C),
+      ValueList(C),
       SeenFirstFunctionBody(false), UseRelativeIDs(false),
       AcceptSupportedBitcodeOnly(AcceptSupportedOnly) {
   }
@@ -213,7 +211,11 @@ public:
     ErrorString = Str;
     return true;
   }
-  const char *getErrorString() const { return ErrorString; }
+  bool Error(const std::string &Str) {
+    ErrorString = Str;
+    return true;
+  }
+  const char *getErrorString() const { return ErrorString.c_str(); }
 
   /// @brief Main interface to parsing a bitcode buffer.
   /// @returns true if an error occurred.
@@ -282,7 +284,6 @@ private:
   bool RememberAndSkipFunctionBody();
   bool ParseFunctionBody(Function *F);
   bool GlobalCleanup();
-  bool ResolveAliasInits();
   bool ParseUseLists();
   bool InitStream();
   bool InitStreamFromBuffer();
diff --git a/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp b/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
index 33d0d84cb5..9884014b4b 100644
--- a/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
+++ b/lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp
@@ -405,15 +405,6 @@ static unsigned getEncodedLinkage(const GlobalValue *GV) {
   llvm_unreachable("Invalid linkage");
 }
 
-static unsigned getEncodedVisibility(const GlobalValue *GV) {
-  switch (GV->getVisibility()) {
-  case GlobalValue::DefaultVisibility:   return 0;
-  case GlobalValue::HiddenVisibility:    return 1;
-  case GlobalValue::ProtectedVisibility: return 2;
-  }
-  llvm_unreachable("Invalid visibility");
-}
-
 /// \brief Function to convert constant initializers for global
 /// variables into corresponding bitcode. Takes advantage that these
 /// global variable initializations are normalized (see
@@ -539,48 +530,6 @@ static void WriteGlobalVars(const Module *M,
 static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
                             NaClBitstreamWriter &Stream) {
   DEBUG(dbgs() << "-> WriteModuleInfo\n");
-  // Emit various pieces of data attached to a module.
-  if (!M->getModuleInlineAsm().empty())
-    WriteStringRecord(naclbitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
-                      0/*TODO*/, Stream);
-
-  // Emit information about sections and GC, computing how many there are. Also
-  // compute the maximum alignment value.
-  // TODO(kschimpf): Remove code for SectionMap and GCMap.
-  std::map<std::string, unsigned> SectionMap;
-  std::map<std::string, unsigned> GCMap;
-  for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
-       GV != E; ++GV) {
-    if (GV->hasSection()) {
-      // Give section names unique ID's.
-      unsigned &Entry = SectionMap[GV->getSection()];
-      if (!Entry) {
-        WriteStringRecord(naclbitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
-                          0/*TODO*/, Stream);
-        Entry = SectionMap.size();
-      }
-    }
-  }
-  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
-    if (F->hasSection()) {
-      // Give section names unique ID's.
-      unsigned &Entry = SectionMap[F->getSection()];
-      if (!Entry) {
-        WriteStringRecord(naclbitc::MODULE_CODE_SECTIONNAME, F->getSection(),
-                          0/*TODO*/, Stream);
-        Entry = SectionMap.size();
-      }
-    }
-    if (F->hasGC()) {
-      // Same for GC names.
-      unsigned &Entry = GCMap[F->getGC()];
-      if (!Entry) {
-        WriteStringRecord(naclbitc::MODULE_CODE_GCNAME, F->getGC(),
-                          0/*TODO*/, Stream);
-        Entry = GCMap.size();
-      }
-    }
-  }
 
   // Emit the function proto information. Note: We do this before
   // global variables, so that global variable initializations can
@@ -600,19 +549,6 @@ static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
 
   // Emit the global variable information.
   WriteGlobalVars(M, VE, Stream);
-
-  // Emit the alias information.
-  for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
-       AI != E; ++AI) {
-    // ALIAS: [alias type, aliasee val#, linkage, visibility]
-    Vals.push_back(VE.getTypeID(AI->getType()));
-    Vals.push_back(VE.getValueID(AI->getAliasee()));
-    Vals.push_back(getEncodedLinkage(AI));
-    Vals.push_back(getEncodedVisibility(AI));
-    unsigned AbbrevToUse = 0;
-    Stream.EmitRecord(naclbitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
-    Vals.clear();
-  }
   DEBUG(dbgs() << "<- WriteModuleInfo\n");
 }