CodeGen for CapturedStmts

EmitCapturedStmt creates a captured struct containing all of the captured
variables, and then emits a call to the outlined function.  This is similar in
principle to EmitBlockLiteral.

GenerateCapturedFunction actually produces the outlined function.  It is based
on GenerateBlockFunction, but is much simpler.  The function type is determined
by the parameters that are in the CapturedDecl.

Some changes have been added to this patch that were reviewed as part of the
serialization patch and moving the parameters to the captured decl.

Differential Revision: http://llvm-reviews.chandlerc.com/D640

llvm-svn: 181536

4 files changed, 171 insertions, 8 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 64670c5e81e..8ba5a1ce522 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1793,6 +1793,13 @@ static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
   return CGF.MakeAddrLValue(V, E->getType(), Alignment);
 }
 
+static LValue EmitCapturedFieldLValue(CodeGenFunction &CGF, const FieldDecl *FD,
+                                      llvm::Value *ThisValue) {
+  QualType TagType = CGF.getContext().getTagDeclType(FD->getParent());
+  LValue LV = CGF.MakeNaturalAlignAddrLValue(ThisValue, TagType);
+  return CGF.EmitLValueForField(LV, FD);
+}
+
 LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
   const NamedDecl *ND = E->getDecl();
   CharUnits Alignment = getContext().getDeclAlign(ND);
@@ -1844,10 +1851,11 @@ LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
     // Use special handling for lambdas.
     if (!V) {
       if (FieldDecl *FD = LambdaCaptureFields.lookup(VD)) {
-        QualType LambdaTagType = getContext().getTagDeclType(FD->getParent());
-        LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue,
-                                                     LambdaTagType);
-        return EmitLValueForField(LambdaLV, FD);
+        return EmitCapturedFieldLValue(*this, FD, CXXABIThisValue);
+      } else if (CapturedStmtInfo) {
+        if (const FieldDecl *FD = CapturedStmtInfo->lookup(VD))
+          return EmitCapturedFieldLValue(*this, FD,
+                                         CapturedStmtInfo->getContextValue());
       }
 
       assert(isa<BlockDecl>(CurCodeDecl) && E->refersToEnclosingLocal());
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 208455c88c7..353d6c3d396 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -22,6 +22,7 @@
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Intrinsics.h"
+#include "llvm/Support/CallSite.h"
 using namespace clang;
 using namespace CodeGen;
 
@@ -137,7 +138,7 @@ void CodeGenFunction::EmitStmt(const Stmt *S) {
   case Stmt::GCCAsmStmtClass:   // Intentional fall-through.
   case Stmt::MSAsmStmtClass:    EmitAsmStmt(cast<AsmStmt>(*S));           break;
   case Stmt::CapturedStmtClass:
-    EmitCapturedStmt(cast<CapturedStmt>(*S));
+    EmitCapturedStmt(cast<CapturedStmt>(*S), CR_Default);
     break;
   case Stmt::ObjCAtTryStmtClass:
     EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
@@ -1750,6 +1751,94 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
   }
 }
 
-void CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S) {
-  llvm_unreachable("not implemented yet");
+static LValue InitCapturedStruct(CodeGenFunction &CGF, const CapturedStmt &S) {
+  const RecordDecl *RD = S.getCapturedRecordDecl();
+  QualType RecordTy = CGF.getContext().getRecordType(RD);
+
+  // Initialize the captured struct.
+  LValue SlotLV = CGF.MakeNaturalAlignAddrLValue(
+                    CGF.CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
+
+  RecordDecl::field_iterator CurField = RD->field_begin();
+  for (CapturedStmt::capture_init_iterator I = S.capture_init_begin(),
+                                           E = S.capture_init_end();
+       I != E; ++I, ++CurField) {
+    LValue LV = CGF.EmitLValueForFieldInitialization(SlotLV, *CurField);
+    CGF.EmitInitializerForField(*CurField, LV, *I, ArrayRef<VarDecl *>());
+  }
+
+  return SlotLV;
+}
+
+/// Generate an outlined function for the body of a CapturedStmt, store any
+/// captured variables into the captured struct, and call the outlined function.
+llvm::Function *
+CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) {
+  const CapturedDecl *CD = S.getCapturedDecl();
+  const RecordDecl *RD = S.getCapturedRecordDecl();
+  assert(CD->hasBody() && "missing CapturedDecl body");
+
+  LValue CapStruct = InitCapturedStruct(*this, S);
+
+  // Emit the CapturedDecl
+  CodeGenFunction CGF(CGM, true);
+  CGF.CapturedStmtInfo = new CGCapturedStmtInfo(S, K);
+  llvm::Function *F = CGF.GenerateCapturedStmtFunction(CD, RD);
+  delete CGF.CapturedStmtInfo;
+
+  // Emit call to the helper function.
+  EmitCallOrInvoke(F, CapStruct.getAddress());
+
+  return F;
+}
+
+/// Creates the outlined function for a CapturedStmt.
+llvm::Function *
+CodeGenFunction::GenerateCapturedStmtFunction(const CapturedDecl *CD,
+                                              const RecordDecl *RD) {
+  assert(CapturedStmtInfo &&
+    "CapturedStmtInfo should be set when generating the captured function");
+
+  // Check if we should generate debug info for this function.
+  maybeInitializeDebugInfo();
+
+  // Build the argument list.
+  ASTContext &Ctx = CGM.getContext();
+  FunctionArgList Args;
+  Args.append(CD->param_begin(), CD->param_end());
+
+  // Create the function declaration.
+  FunctionType::ExtInfo ExtInfo;
+  const CGFunctionInfo &FuncInfo =
+    CGM.getTypes().arrangeFunctionDeclaration(Ctx.VoidTy, Args, ExtInfo,
+                                              /*IsVariadic=*/false);
+  llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
+
+  llvm::Function *F =
+    llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage,
+                           CapturedStmtInfo->getHelperName(), &CGM.getModule());
+  CGM.SetInternalFunctionAttributes(CD, F, FuncInfo);
+
+  // Generate the function.
+  StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args, CD->getBody()->getLocStart());
+
+  // Set the context parameter in CapturedStmtInfo.
+  llvm::Value *DeclPtr = LocalDeclMap[CD->getContextParam()];
+  assert(DeclPtr && "missing context parameter for CapturedStmt");
+  CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr));
+
+  // If 'this' is captured, load it into CXXThisValue.
+  if (CapturedStmtInfo->isCXXThisExprCaptured()) {
+    FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl();
+    LValue LV = MakeNaturalAlignAddrLValue(CapturedStmtInfo->getContextValue(),
+                                           Ctx.getTagDeclType(RD));
+    LValue ThisLValue = EmitLValueForField(LV, FD);
+
+    CXXThisValue = EmitLoadOfLValue(ThisLValue).getScalarVal();
+  }
+
+  CapturedStmtInfo->EmitBody(*this, CD->getBody());
+  FinishFunction(CD->getBodyRBrace());
+
+  return F;
 }
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 75c60edbba5..071c08e6bf2 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -33,6 +33,7 @@ using namespace CodeGen;
 CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext)
   : CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()),
     Builder(cgm.getModule().getContext()),
+    CapturedStmtInfo(0),
     SanitizePerformTypeCheck(CGM.getSanOpts().Null |
                              CGM.getSanOpts().Alignment |
                              CGM.getSanOpts().ObjectSize |
@@ -1447,3 +1448,5 @@ llvm::Value *CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D,
 
   return V;
 }
+
+CodeGenFunction::CGCapturedStmtInfo::~CGCapturedStmtInfo() { }
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index ff74c15c38c..6caf1689a9d 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -23,6 +23,7 @@
 #include "clang/AST/ExprObjC.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/ABI.h"
+#include "clang/Basic/CapturedStmt.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Frontend/CodeGenOptions.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -606,6 +607,65 @@ public:
   /// we prefer to insert allocas.
   llvm::AssertingVH<llvm::Instruction> AllocaInsertPt;
 
+  /// \brief API for captured statement code generation.
+  class CGCapturedStmtInfo {
+  public:
+    explicit CGCapturedStmtInfo(const CapturedStmt &S,
+                                CapturedRegionKind K = CR_Default)
+      : Kind(K), ThisValue(0), CXXThisFieldDecl(0) {
+
+      RecordDecl::field_iterator Field =
+        S.getCapturedRecordDecl()->field_begin();
+      for (CapturedStmt::const_capture_iterator I = S.capture_begin(),
+                                                E = S.capture_end();
+           I != E; ++I, ++Field) {
+        if (I->capturesThis())
+          CXXThisFieldDecl = *Field;
+        else
+          CaptureFields[I->getCapturedVar()] = *Field;
+      }
+    }
+
+    virtual ~CGCapturedStmtInfo();
+
+    CapturedRegionKind getKind() const { return Kind; }
+
+    void setContextValue(llvm::Value *V) { ThisValue = V; }
+    // \brief Retrieve the value of the context parameter.
+    llvm::Value *getContextValue() const { return ThisValue; }
+
+    /// \brief Lookup the captured field decl for a variable.
+    const FieldDecl *lookup(const VarDecl *VD) const {
+      return CaptureFields.lookup(VD);
+    }
+
+    bool isCXXThisExprCaptured() const { return CXXThisFieldDecl != 0; }
+    FieldDecl *getThisFieldDecl() const { return CXXThisFieldDecl; }
+
+    /// \brief Emit the captured statement body.
+    virtual void EmitBody(CodeGenFunction &CGF, Stmt *S) {
+      CGF.EmitStmt(S);
+    }
+
+    /// \brief Get the name of the capture helper.
+    virtual StringRef getHelperName() const { return "__captured_stmt"; }
+
+  private:
+    /// \brief The kind of captured statement being generated.
+    CapturedRegionKind Kind;
+
+    /// \brief Keep the map between VarDecl and FieldDecl.
+    llvm::SmallDenseMap<const VarDecl *, FieldDecl *> CaptureFields;
+
+    /// \brief The base address of the captured record, passed in as the first
+    /// argument of the parallel region function.
+    llvm::Value *ThisValue;
+
+    /// \brief Captured 'this' type.
+    FieldDecl *CXXThisFieldDecl;
+  };
+  CGCapturedStmtInfo *CapturedStmtInfo;
+
   /// BoundsChecking - Emit run-time bounds checks. Higher values mean
   /// potentially higher performance penalties.
   unsigned char BoundsChecking;
@@ -2188,7 +2248,6 @@ public:
   void EmitCaseStmt(const CaseStmt &S);
   void EmitCaseStmtRange(const CaseStmt &S);
   void EmitAsmStmt(const AsmStmt &S);
-  void EmitCapturedStmt(const CapturedStmt &S);
 
   void EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S);
   void EmitObjCAtTryStmt(const ObjCAtTryStmt &S);
@@ -2204,6 +2263,10 @@ public:
   void EmitCXXTryStmt(const CXXTryStmt &S);
   void EmitCXXForRangeStmt(const CXXForRangeStmt &S);
 
+  llvm::Function *EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K);
+  llvm::Function *GenerateCapturedStmtFunction(const CapturedDecl *CD,
+                                               const RecordDecl *RD);
+
   //===--------------------------------------------------------------------===//
   //                         LValue Expression Emission
   //===--------------------------------------------------------------------===//