1 files changed, 211 insertions, 0 deletions
diff --git a/lib/Sema/SemaAttr.cpp b/lib/Sema/SemaAttr.cpp
new file mode 100644
index 0000000..1bf8444
--- /dev/null
+++ b/lib/Sema/SemaAttr.cpp
@@ -0,0 +1,211 @@
+//===--- SemaAttr.cpp - Semantic Analysis for Attributes ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements semantic analysis for non-trivial attributes and
+// pragmas.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Sema.h"
+#include "clang/AST/Expr.h"
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// Pragma Packed
+//===----------------------------------------------------------------------===//
+
+namespace {
+  /// PragmaPackStack - Simple class to wrap the stack used by #pragma
+  /// pack.
+  class PragmaPackStack {
+    typedef std::vector< std::pair<unsigned, IdentifierInfo*> > stack_ty;
+
+    /// Alignment - The current user specified alignment.
+    unsigned Alignment;
+
+    /// Stack - Entries in the #pragma pack stack, consisting of saved
+    /// alignments and optional names.
+    stack_ty Stack;
+    
+  public:  
+    PragmaPackStack() : Alignment(0) {}
+
+    void setAlignment(unsigned A) { Alignment = A; }
+    unsigned getAlignment() { return Alignment; }
+
+    /// push - Push the current alignment onto the stack, optionally
+    /// using the given \arg Name for the record, if non-zero.
+    void push(IdentifierInfo *Name) {
+      Stack.push_back(std::make_pair(Alignment, Name));
+    }
+
+    /// pop - Pop a record from the stack and restore the current
+    /// alignment to the previous value. If \arg Name is non-zero then
+    /// the first such named record is popped, otherwise the top record
+    /// is popped. Returns true if the pop succeeded.
+    bool pop(IdentifierInfo *Name);
+  };
+}  // end anonymous namespace.
+
+bool PragmaPackStack::pop(IdentifierInfo *Name) {
+  if (Stack.empty())
+    return false;
+  
+  // If name is empty just pop top.
+  if (!Name) {
+    Alignment = Stack.back().first;
+    Stack.pop_back();
+    return true;
+  } 
+  
+  // Otherwise, find the named record.
+  for (unsigned i = Stack.size(); i != 0; ) {
+    --i;
+    if (Stack[i].second == Name) {
+      // Found it, pop up to and including this record.
+      Alignment = Stack[i].first;
+      Stack.erase(Stack.begin() + i, Stack.end());
+      return true;
+    }
+  }
+  
+  return false;
+}
+
+
+/// FreePackedContext - Deallocate and null out PackContext.
+void Sema::FreePackedContext() {
+  delete static_cast<PragmaPackStack*>(PackContext);
+  PackContext = 0;
+}
+
+/// getPragmaPackAlignment() - Return the current alignment as specified by
+/// the current #pragma pack directive, or 0 if none is currently active.
+unsigned Sema::getPragmaPackAlignment() const {
+  if (PackContext)
+    return static_cast<PragmaPackStack*>(PackContext)->getAlignment();
+  return 0;
+}
+
+void Sema::ActOnPragmaPack(PragmaPackKind Kind, IdentifierInfo *Name, 
+                           ExprTy *alignment, SourceLocation PragmaLoc, 
+                           SourceLocation LParenLoc, SourceLocation RParenLoc) {
+  Expr *Alignment = static_cast<Expr *>(alignment);
+
+  // If specified then alignment must be a "small" power of two.
+  unsigned AlignmentVal = 0;
+  if (Alignment) {
+    llvm::APSInt Val;
+    
+    // pack(0) is like pack(), which just works out since that is what
+    // we use 0 for in PackAttr.
+    if (!Alignment->isIntegerConstantExpr(Val, Context) ||
+        !(Val == 0 || Val.isPowerOf2()) ||
+        Val.getZExtValue() > 16) {
+      Diag(PragmaLoc, diag::warn_pragma_pack_invalid_alignment);
+      Alignment->Destroy(Context);
+      return; // Ignore
+    }
+
+    AlignmentVal = (unsigned) Val.getZExtValue();
+  }
+  
+  if (PackContext == 0)
+    PackContext = new PragmaPackStack();
+  
+  PragmaPackStack *Context = static_cast<PragmaPackStack*>(PackContext);
+  
+  switch (Kind) {
+  case Action::PPK_Default: // pack([n])
+    Context->setAlignment(AlignmentVal);
+    break;
+
+  case Action::PPK_Show: // pack(show)
+    // Show the current alignment, making sure to show the right value
+    // for the default.
+    AlignmentVal = Context->getAlignment();
+    // FIXME: This should come from the target.
+    if (AlignmentVal == 0)
+      AlignmentVal = 8;
+    Diag(PragmaLoc, diag::warn_pragma_pack_show) << AlignmentVal;
+    break;
+
+  case Action::PPK_Push: // pack(push [, id] [, [n])
+    Context->push(Name);
+    // Set the new alignment if specified.
+    if (Alignment)
+      Context->setAlignment(AlignmentVal);    
+    break;
+
+  case Action::PPK_Pop: // pack(pop [, id] [,  n])
+    // MSDN, C/C++ Preprocessor Reference > Pragma Directives > pack:
+    // "#pragma pack(pop, identifier, n) is undefined"
+    if (Alignment && Name)
+      Diag(PragmaLoc, diag::warn_pragma_pack_pop_identifer_and_alignment);    
+    
+    // Do the pop.
+    if (!Context->pop(Name)) {
+      // If a name was specified then failure indicates the name
+      // wasn't found. Otherwise failure indicates the stack was
+      // empty.
+      Diag(PragmaLoc, diag::warn_pragma_pack_pop_failed)
+        << (Name ? "no record matching name" : "stack empty");
+
+      // FIXME: Warn about popping named records as MSVC does.
+    } else {
+      // Pop succeeded, set the new alignment if specified.
+      if (Alignment)
+        Context->setAlignment(AlignmentVal);
+    }
+    break;
+
+  default:
+    assert(0 && "Invalid #pragma pack kind.");
+  }
+}
+
+void Sema::ActOnPragmaUnused(ExprTy **Exprs, unsigned NumExprs,
+                             SourceLocation PragmaLoc,
+                             SourceLocation LParenLoc,
+                             SourceLocation RParenLoc) {
+  
+  // Verify that all of the expressions are valid before
+  // modifying the attributes of any referenced decl.
+  Expr *ErrorExpr = 0;
+  
+  for (unsigned i = 0; i < NumExprs; ++i) {  
+    Expr *Ex = (Expr*) Exprs[i];
+    if (!isa<DeclRefExpr>(Ex)) {
+      ErrorExpr = Ex;
+      break;
+    }
+
+    Decl *d = cast<DeclRefExpr>(Ex)->getDecl();;
+
+    if (!isa<VarDecl>(d) || !cast<VarDecl>(d)->hasLocalStorage()) {
+      ErrorExpr = Ex;
+      break;
+    }
+  }
+  
+  // Delete the expressions if we encountered any error.
+  if (ErrorExpr) {
+    Diag(ErrorExpr->getLocStart(), diag::warn_pragma_unused_expected_localvar);
+    for (unsigned i = 0; i < NumExprs; ++i)
+      ((Expr*) Exprs[i])->Destroy(Context);    
+    return;
+  }
+      
+  // Otherwise, add the 'unused' attribute to each referenced declaration.
+  for (unsigned i = 0; i < NumExprs; ++i) {
+    DeclRefExpr *DR = (DeclRefExpr*) Exprs[i];
+    DR->getDecl()->addAttr(::new (Context) UnusedAttr());
+    DR->Destroy(Context);
+  }
+}