Add preliminary (and probably broken) codegen support for C++ static initializers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@55180 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 136 insertions, 0 deletions

diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
new file mode 100644
index 0000000000..76e044bd9f
--- /dev/null
+++ b/lib/CodeGen/CGCXX.cpp
@@ -0,0 +1,136 @@
+//===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code dealing with C++ code generation.
+//
+//===----------------------------------------------------------------------===//
+
+// We might split this into multiple files if it gets too unwieldy 
+
+#include "CodeGenFunction.h"
+#include "CodeGenModule.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
+#include "llvm/ADT/StringExtras.h"
+
+using namespace clang;
+using namespace CodeGen;
+
+using llvm::utostr;
+
+
+// FIXME: Name mangling should be moved to a separate class.
+
+static void mangleDeclContextInternal(const DeclContext *D, std::string &S)
+{
+  assert(isa<TranslationUnitDecl>(D->getParent()) && 
+         "Only one level of decl context mangling is currently supported!");
+  
+  if (FunctionDecl* FD = dyn_cast<FunctionDecl>(D)) {
+    S += utostr(FD->getIdentifier()->getLength());
+    S += FD->getIdentifier()->getName();
+    
+    if (FD->param_size() == 0)
+      S += 'v';
+    else
+      assert(0 && "mangling of types not supported yet!");
+  } else 
+    assert(0 && "Unsupported decl type!");
+}
+
+static void mangleVarDeclInternal(const VarDecl &D, std::string &S)
+{
+  S += 'Z';
+  mangleDeclContextInternal(D.getDeclContext(), S);
+  S += 'E';
+  
+  S += utostr(D.getIdentifier()->getLength());
+  S += D.getIdentifier()->getName();
+}
+
+static std::string mangleVarDecl(const VarDecl& D)
+{
+  std::string S = "_Z";
+  
+  mangleVarDeclInternal(D, S);
+  
+  return S;
+}
+
+static std::string mangleGuardVariable(const VarDecl& D)
+{
+  std::string S = "_ZGV";
+
+  mangleVarDeclInternal(D, S);
+  
+  return S;
+}
+
+llvm::GlobalValue *
+CodeGenFunction::GenerateStaticCXXBlockVarDecl(const VarDecl &D)
+{
+  assert(!getContext().getLangOptions().ThreadsafeStatics &&
+         "thread safe statics are currently not supported!");
+  const llvm::Type *LTy = CGM.getTypes().ConvertTypeForMem(D.getType());
+
+  // FIXME: If the function is inline, the linkage should be weak.
+  llvm::GlobalValue::LinkageTypes linkage = llvm::GlobalValue::InternalLinkage;
+  
+  // Create the guard variable.
+  llvm::GlobalValue *GuardV = 
+    new llvm::GlobalVariable(llvm::Type::Int64Ty, false,
+                             linkage,
+                             llvm::Constant::getNullValue(llvm::Type::Int64Ty),
+                             mangleGuardVariable(D),
+                             &CGM.getModule());
+  
+  // FIXME: Address space.
+  const llvm::Type *PtrTy = llvm::PointerType::get(llvm::Type::Int8Ty, 0);
+
+  // Load the first byte of the guard variable.
+  llvm::Value *V = Builder.CreateLoad(Builder.CreateBitCast(GuardV, PtrTy), 
+                                      "tmp");
+  
+  // Compare it against 0.
+  llvm::Value *nullValue = llvm::Constant::getNullValue(llvm::Type::Int8Ty);
+  llvm::Value *ICmp = Builder.CreateICmpEQ(V, nullValue , "tobool");
+  
+  llvm::BasicBlock *InitBlock = llvm::BasicBlock::Create("init");
+  llvm::BasicBlock *EndBlock = llvm::BasicBlock::Create("initend");
+
+  // If the guard variable is 0, jump to the initializer code.
+  Builder.CreateCondBr(ICmp, InitBlock, EndBlock);
+                         
+  EmitBlock(InitBlock);
+
+  llvm::GlobalValue *GV =
+    new llvm::GlobalVariable(LTy, false,
+                             llvm::GlobalValue::InternalLinkage,
+                             llvm::Constant::getNullValue(LTy), 
+                             mangleVarDecl(D),
+                             &CGM.getModule(), 0, 
+                             D.getType().getAddressSpace());
+    
+  const Expr *Init = D.getInit();
+  if (!hasAggregateLLVMType(Init->getType())) {
+    llvm::Value *V = EmitScalarExpr(Init);
+    Builder.CreateStore(V, GV, D.getType().isVolatileQualified());
+  } else if (Init->getType()->isAnyComplexType()) {
+    EmitComplexExprIntoAddr(Init, GV, D.getType().isVolatileQualified());
+  } else {
+    EmitAggExpr(Init, GV, D.getType().isVolatileQualified());
+  }
+    
+  Builder.CreateStore(llvm::ConstantInt::get(llvm::Type::Int8Ty, 1),
+                      Builder.CreateBitCast(GuardV, PtrTy));
+                      
+  EmitBlock(EndBlock);
+  return GV;
+}
+