[llvm] r235911 - [opaque pointer type] encode the pointee type of global variables

[David Blaikie]

Author: dblaikie
Date: Mon Apr 27 14:58:56 2015
New Revision: 235911

URL: http://llvm.org/viewvc/llvm-project?rev=235911&view=rev
Log:
[opaque pointer type] encode the pointee type of global variables

Use a few extra bits in the const field (after widening it from a fixed
single bit) to stash the address space which is no longer provided by
the type (and an extra bit in there to specify that we're using that new
encoding).

Modified:
    llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
    llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp

Modified: llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp?rev=235911&r1=235910&r2=235911&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp (original)
+++ llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp Mon Apr 27 14:58:56 2015
@@ -2876,12 +2876,18 @@ std::error_code BitcodeReader::ParseModu
       Type *Ty = getTypeByID(Record[0]);
       if (!Ty)
         return Error("Invalid record");
-      if (!Ty->isPointerTy())
-        return Error("Invalid type for value");
-      unsigned AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
-      Ty = cast<PointerType>(Ty)->getElementType();
+      bool isConstant = Record[1] & 1;
+      bool explicitType = Record[1] & 2;
+      unsigned AddressSpace;
+      if (explicitType) {
+        AddressSpace = Record[1] >> 2;
+      } else {
+        if (!Ty->isPointerTy())
+          return Error("Invalid type for value");
+        AddressSpace = cast<PointerType>(Ty)->getAddressSpace();
+        Ty = cast<PointerType>(Ty)->getElementType();
+      }
 
-      bool isConstant = Record[1];
       uint64_t RawLinkage = Record[3];
       GlobalValue::LinkageTypes Linkage = getDecodedLinkage(RawLinkage);
       unsigned Alignment;

Modified: llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp?rev=235911&r1=235910&r2=235911&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp (original)
+++ llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp Mon Apr 27 14:58:56 2015
@@ -590,7 +590,7 @@ static void WriteModuleInfo(const Module
   unsigned MaxGlobalType = 0;
   for (const GlobalValue &GV : M->globals()) {
     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
-    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getType()));
+    MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
     if (GV.hasSection()) {
       // Give section names unique ID's.
       unsigned &Entry = SectionMap[GV.getSection()];
@@ -631,10 +631,12 @@ static void WriteModuleInfo(const Module
     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
                               Log2_32_Ceil(MaxGlobalType+1)));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));      // Constant.
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));        // Initializer.
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5));      // Linkage.
-    if (MaxAlignment == 0)                                      // Alignment.
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
+                                                           //| explicitType << 1
+                                                           //| constant
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
+    if (MaxAlignment == 0)                                 // Alignment.
       Abbv->Add(BitCodeAbbrevOp(0));
     else {
       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
@@ -659,8 +661,8 @@ static void WriteModuleInfo(const Module
     //             linkage, alignment, section, visibility, threadlocal,
     //             unnamed_addr, externally_initialized, dllstorageclass,
     //             comdat]
-    Vals.push_back(VE.getTypeID(GV.getType()));
-    Vals.push_back(GV.isConstant());
+    Vals.push_back(VE.getTypeID(GV.getValueType()));
+    Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
     Vals.push_back(GV.isDeclaration() ? 0 :
                    (VE.getValueID(GV.getInitializer()) + 1));
     Vals.push_back(getEncodedLinkage(GV));