[llvm][Bitcode] Add bitcode reader/writer for DSOLocalEquivalent

This is necessary for compilation with [thin]lto.

Differential Revision: https://reviews.llvm.org/D96170

llvm/include/llvm/Bitcode/LLVMBitCodes.h

@@ -375,8 +375,9 @@ enum ConstantsCodes {
   CST_CODE_INLINEASM = 23,       // INLINEASM:     [sideeffect|alignstack|
                                  //                 asmdialect,asmstr,conststr]
   CST_CODE_CE_GEP_WITH_INRANGE_INDEX = 24, //      [opty, flags, n x operands]
-  CST_CODE_CE_UNOP = 25,         // CE_UNOP:      [opcode, opval]
-  CST_CODE_POISON = 26,          // POISON
+  CST_CODE_CE_UNOP = 25,                   // CE_UNOP:      [opcode, opval]
+  CST_CODE_POISON = 26,                    // POISON
+  CST_CODE_DSO_LOCAL_EQUIVALENT = 27,      // DSO_LOCAL_EQUIVALENT [gvty, gv]
 };
 
 /// CastOpcodes - These are values used in the bitcode files to encode which

llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp

@@ -218,6 +218,7 @@ static Optional<const char *> GetCodeName(unsigned CodeID, unsigned BlockID,
       STRINGIFY_CODE(CST_CODE, INLINEASM)
       STRINGIFY_CODE(CST_CODE, CE_SHUFVEC_EX)
       STRINGIFY_CODE(CST_CODE, CE_UNOP)
+      STRINGIFY_CODE(CST_CODE, DSO_LOCAL_EQUIVALENT)
     case bitc::CST_CODE_BLOCKADDRESS:
       return "CST_CODE_BLOCKADDRESS";
       STRINGIFY_CODE(CST_CODE, DATA)

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -2888,6 +2888,20 @@ Error BitcodeReader::parseConstants() {
       V = BlockAddress::get(Fn, BB);
       break;
     }
+    case bitc::CST_CODE_DSO_LOCAL_EQUIVALENT: {
+      if (Record.size() < 2)
+        return error("Invalid record");
+      Type *GVTy = getTypeByID(Record[0]);
+      if (!GVTy)
+        return error("Invalid record");
+      GlobalValue *GV = dyn_cast_or_null<GlobalValue>(
+          ValueList.getConstantFwdRef(Record[1], GVTy));
+      if (!GV)
+        return error("Invalid record");
+
+      V = DSOLocalEquivalent::get(GV);
+      break;
+    }
     }
 
     assert(V->getType() == flattenPointerTypes(CurFullTy) &&

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -2609,6 +2609,10 @@ void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
       Record.push_back(VE.getValueID(BA->getFunction()));
       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
+    } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
+      Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
+      Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
+      Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
     } else {
 #ifndef NDEBUG
       C->dump();

llvm/test/Bitcode/dso_local_equivalent.ll

@@ -0,0 +1,86 @@
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+; RUN: verify-uselistorder < %s
+
+declare void @extern_func()
+
+define void @call_extern_func() {
+; CHECK: call void dso_local_equivalent @extern_func()
+  call void dso_local_equivalent @extern_func()
+  ret void
+}
+
+declare hidden void @hidden_func()
+declare protected void @protected_func()
+declare dso_local void @dso_local_func()
+define internal void @internal_func() {
+entry:
+  ret void
+}
+define private void @private_func() {
+entry:
+  ret void
+}
+
+; CHECK: call void dso_local_equivalent @hidden_func()
+define void @call_hidden_func() {
+  call void dso_local_equivalent @hidden_func()
+  ret void
+}
+
+define void @call_protected_func() {
+; CHECK: call void dso_local_equivalent @protected_func()
+  call void dso_local_equivalent @protected_func()
+  ret void
+}
+
+define void @call_dso_local_func() {
+; CHECK: call void dso_local_equivalent @dso_local_func()
+  call void dso_local_equivalent @dso_local_func()
+  ret void
+}
+
+define void @call_internal_func() {
+; CHECK: call void dso_local_equivalent @internal_func()
+  call void dso_local_equivalent @internal_func()
+  ret void
+}
+
+define void @aliasee_func() {
+entry:
+  ret void
+}
+
+@alias_func = alias void (), void ()* @aliasee_func
+@dso_local_alias_func = dso_local alias void (), void ()* @aliasee_func
+
+define void @call_alias_func() {
+; CHECK: call void dso_local_equivalent @alias_func()
+  call void dso_local_equivalent @alias_func()
+  ret void
+}
+
+define void @call_dso_local_alias_func() {
+; CHECK: call void dso_local_equivalent @dso_local_alias_func()
+  call void dso_local_equivalent @dso_local_alias_func()
+  ret void
+}
+
+@ifunc_func = ifunc void (), i64 ()* @resolver
+@dso_local_ifunc_func = dso_local ifunc void (), i64 ()* @resolver
+
+define internal i64 @resolver() {
+entry:
+  ret i64 0
+}
+
+define void @call_ifunc_func() {
+; CHECK: call void dso_local_equivalent @ifunc_func()
+  call void dso_local_equivalent @ifunc_func()
+  ret void
+}
+
+define void @call_dso_local_ifunc_func() {
+; CHECK: call void dso_local_equivalent @dso_local_ifunc_func()
+  call void dso_local_equivalent @dso_local_ifunc_func()
+  ret void
+}