path: root/lib/CodeGen/CGStmt.cpp

//===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Stmt nodes as LLVM code.
//
//===----------------------------------------------------------------------===//

#include "CGDebugInfo.h"
#include "CodeGenModule.h"
#include "CodeGenFunction.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/PrettyStackTrace.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/InlineAsm.h"
#include "llvm/Intrinsics.h"
#include "llvm/Target/TargetData.h"
using namespace clang;
using namespace CodeGen;

//===----------------------------------------------------------------------===//
//                              Statement Emission
//===----------------------------------------------------------------------===//

void CodeGenFunction::EmitStopPoint(const Stmt *S) {
  if (CGDebugInfo *DI = getDebugInfo()) {
    if (isa<DeclStmt>(S))
      DI->setLocation(S->getLocEnd());
    else
      DI->setLocation(S->getLocStart());
    DI->EmitStopPoint(CurFn, Builder);
  }
}

void CodeGenFunction::EmitStmt(const Stmt *S) {
  assert(S && "Null statement?");

  // Check if we can handle this without bothering to generate an
  // insert point or debug info.
  if (EmitSimpleStmt(S))
    return;

  // Check if we are generating unreachable code.
  if (!HaveInsertPoint()) {
    // If so, and the statement doesn't contain a label, then we do not need to
    // generate actual code. This is safe because (1) the current point is
    // unreachable, so we don't need to execute the code, and (2) we've already
    // handled the statements which update internal data structures (like the
    // local variable map) which could be used by subsequent statements.
    if (!ContainsLabel(S)) {
      // Verify that any decl statements were handled as simple, they may be in
      // scope of subsequent reachable statements.
      assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
      return;
    }

    // Otherwise, make a new block to hold the code.
    EnsureInsertPoint();
  }

  // Generate a stoppoint if we are emitting debug info.
  EmitStopPoint(S);

  switch (S->getStmtClass()) {
  default:
    // Must be an expression in a stmt context.  Emit the value (to get
    // side-effects) and ignore the result.
    if (!isa<Expr>(S))
      ErrorUnsupported(S, "statement");

    EmitAnyExpr(cast<Expr>(S), 0, false, true);

    // Expression emitters don't handle unreachable blocks yet, so look for one
    // explicitly here. This handles the common case of a call to a noreturn
    // function.
    if (llvm::BasicBlock *CurBB = Builder.GetInsertBlock()) {
      if (CurBB->empty() && CurBB->use_empty()) {
        CurBB->eraseFromParent();
        Builder.ClearInsertionPoint();
      }
    }
    break;
  case Stmt::IndirectGotoStmtClass:
    EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;

  case Stmt::IfStmtClass:       EmitIfStmt(cast<IfStmt>(*S));             break;
  case Stmt::WhileStmtClass:    EmitWhileStmt(cast<WhileStmt>(*S));       break;
  case Stmt::DoStmtClass:       EmitDoStmt(cast<DoStmt>(*S));             break;
  case Stmt::ForStmtClass:      EmitForStmt(cast<ForStmt>(*S));           break;

  case Stmt::ReturnStmtClass:   EmitReturnStmt(cast<ReturnStmt>(*S));     break;

  case Stmt::SwitchStmtClass:   EmitSwitchStmt(cast<SwitchStmt>(*S));     break;
  case Stmt::AsmStmtClass:      EmitAsmStmt(cast<AsmStmt>(*S));           break;

  case Stmt::ObjCAtTryStmtClass:
    EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
    break;
  case Stmt::ObjCAtCatchStmtClass:
    assert