Fix alignment issues in Clang.

Some const-correctness changes snuck in here too, since they were in the
area of code I was modifying.

This seems to make Clang actually work without Bus Error on
32bit-sparc.

Follow-up patches will factor out a trailing-object helper class, to
make classes using the idiom of appending objects to other objects
easier to understand, and to ensure (with static_assert) that required
alignment guarantees continue to hold.

Differential Revision: http://reviews.llvm.org/D10272

llvm-svn: 242554

11 files changed, 88 insertions, 38 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index ea4b2f517cd..946d1bae21e 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -3116,8 +3116,8 @@ FunctionDecl::setDependentTemplateSpecialization(ASTContext &Context,
                              const TemplateArgumentListInfo &TemplateArgs) {
   assert(TemplateOrSpecialization.isNull());
   size_t Size = sizeof(DependentFunctionTemplateSpecializationInfo);
-  Size += Templates.size() * sizeof(FunctionTemplateDecl*);
   Size += TemplateArgs.size() * sizeof(TemplateArgumentLoc);
+  Size += Templates.size() * sizeof(FunctionTemplateDecl *);
   void *Buffer = Context.Allocate(Size);
   DependentFunctionTemplateSpecializationInfo *Info =
     new (Buffer) DependentFunctionTemplateSpecializationInfo(Templates,
@@ -3132,8 +3132,8 @@ DependentFunctionTemplateSpecializationInfo(const UnresolvedSetImpl &Ts,
   static_assert(sizeof(*this) % llvm::AlignOf<void *>::Alignment == 0,
                 "Trailing data is unaligned!");
 
-  d.NumTemplates = Ts.size();
-  d.NumArgs = TArgs.size();
+  NumTemplates = Ts.size();
+  NumArgs = TArgs.size();
 
   FunctionTemplateDecl **TsArray =
     const_cast<FunctionTemplateDecl**>(getTemplates());
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 4fcec53d6eb..e772f195336 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -45,10 +45,19 @@ void Decl::updateOutOfDate(IdentifierInfo &II) const {
   getASTContext().getExternalSource()->updateOutOfDateIdentifier(II);
 }
 
+#define DECL(DERIVED, BASE)                                                    \
+  static_assert(Decl::DeclObjAlignment >=                                      \
+                    llvm::AlignOf<DERIVED##Decl>::Alignment,                   \
+                "Alignment sufficient after objects prepended to " #DERIVED);
+#define ABSTRACT_DECL(DECL)
+#include "clang/AST/DeclNodes.inc"
+
 void *Decl::operator new(std::size_t Size, const ASTContext &Context,
                          unsigned ID, std::size_t Extra) {
   // Allocate an extra 8 bytes worth of storage, which ensures that the
-  // resulting pointer will still be 8-byte aligned. 
+  // resulting pointer will still be 8-byte aligned.
+  static_assert(sizeof(unsigned) * 2 >= DeclObjAlignment,
+                "Decl won't be misaligned");
   void *Start = Context.Allocate(Size + Extra + 8);
   void *Result = (char*)Start + 8;
 
@@ -69,7 +78,13 @@ void *Decl::operator new(std::size_t Size, const ASTContext &Ctx,
   // With local visibility enabled, we track the owning module even for local
   // declarations.
   if (Ctx.getLangOpts().ModulesLocalVisibility) {
-    void *Buffer = ::operator new(sizeof(Module *) + Size + Extra, Ctx);
+    // Ensure required alignment of the resulting object by adding extra
+    // padding at the start if required.
+    size_t ExtraAlign =
+        llvm::OffsetToAlignment(sizeof(Module *), DeclObjAlignment);
+    char *Buffer = reinterpret_cast<char *>(
+        ::operator new(ExtraAlign + sizeof(Module *) + Size + Extra, Ctx));
+    Buffer += ExtraAlign;
     return new (Buffer) Module*(nullptr) + 1;
   }
   return ::operator new(Size + Extra, Ctx);
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 2e066b2c42c..6c048f96d45 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -399,10 +399,15 @@ DeclRefExpr *DeclRefExpr::Create(const ASTContext &Context,
     Size += sizeof(NestedNameSpecifierLoc);
   if (FoundD)
     Size += sizeof(NamedDecl *);
-  if (TemplateArgs)
+  if (TemplateArgs) {
+    Size = llvm::RoundUpToAlignment(Size,
+                                    llvm::alignOf<ASTTemplateKWAndArgsInfo>());
     Size += ASTTemplateKWAndArgsInfo::sizeFor(TemplateArgs->size());
-  else if (TemplateKWLoc.isValid())
+  } else if (TemplateKWLoc.isValid()) {
+    Size = llvm::RoundUpToAlignment(Size,
+                                    llvm::alignOf<ASTTemplateKWAndArgsInfo>());
     Size += ASTTemplateKWAndArgsInfo::sizeFor(0);
+  }
 
   void *Mem = Context.Allocate(Size, llvm::alignOf<DeclRefExpr>());
   return new (Mem) DeclRefExpr(Context, QualifierLoc, TemplateKWLoc, D,
@@ -420,8 +425,11 @@ DeclRefExpr *DeclRefExpr::CreateEmpty(const ASTContext &Context,
     Size += sizeof(NestedNameSpecifierLoc);
   if (HasFoundDecl)
     Size += sizeof(NamedDecl *);
-  if (HasTemplateKWAndArgsInfo)
+  if (HasTemplateKWAndArgsInfo) {
+    Size = llvm::RoundUpToAlignment(Size,
+                                    llvm::alignOf<ASTTemplateKWAndArgsInfo>());
     Size += ASTTemplateKWAndArgsInfo::sizeFor(NumTemplateArgs);
+  }
 
   void *Mem = Context.Allocate(Size, llvm::alignOf<DeclRefExpr>());
   return new (Mem) DeclRefExpr(EmptyShell());
@@ -3939,7 +3947,8 @@ DesignatedInitExpr::Create(const ASTContext &C, Designator *Designators,
                            SourceLocation ColonOrEqualLoc,
                            bool UsesColonSyntax, Expr *Init) {
   void *Mem = C.Allocate(sizeof(DesignatedInitExpr) +
-                         sizeof(Stmt *) * (IndexExprs.size() + 1), 8);
+                             sizeof(Stmt *) * (IndexExprs.size() + 1),
+                         llvm::alignOf<DesignatedInitExpr>());
   return new (Mem) DesignatedInitExpr(C, C.VoidTy, NumDesignators, Designators,
                                       ColonOrEqualLoc, UsesColonSyntax,
                                       IndexExprs, Init);
diff --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index d6f2ce63a0a..2a93f71429e 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -1070,15 +1070,15 @@ LambdaExpr::capture_range LambdaExpr::implicit_captures() const {
   return capture_range(implicit_capture_begin(), implicit_capture_end());
 }
 
-ArrayRef<VarDecl *> 
-LambdaExpr::getCaptureInitIndexVars(capture_init_iterator Iter) const {
+ArrayRef<VarDecl *>
+LambdaExpr::getCaptureInitIndexVars(const_capture_init_iterator Iter) const {
   assert(HasArrayIndexVars && "No array index-var data?");
   
   unsigned Index = Iter - capture_init_begin();
   assert(Index < getLambdaClass()->getLambdaData().NumCaptures &&
          "Capture index out-of-range");
-  VarDecl **IndexVars = getArrayIndexVars();
-  unsigned *IndexStarts = getArrayIndexStarts();
+  VarDecl *const *IndexVars = getArrayIndexVars();
+  const unsigned *IndexStarts = getArrayIndexStarts();
   return llvm::makeArrayRef(IndexVars + IndexStarts[Index],
                             IndexVars + IndexStarts[Index + 1]);
 }
@@ -1099,9 +1099,13 @@ TemplateParameterList *LambdaExpr::getTemplateParameterList() const {
 }
 
 CompoundStmt *LambdaExpr::getBody() const {
+  // FIXME: this mutation in getBody is bogus. It should be
+  // initialized in ASTStmtReader::VisitLambdaExpr, but for reasons I
+  // don't understand, that doesn't work.
   if (!getStoredStmts()[NumCaptures])
-    getStoredStmts()[NumCaptures] = getCallOperator()->getBody();
-    
+    *const_cast<clang::Stmt **>(&getStoredStmts()[NumCaptures]) =
+        getCallOperator()->getBody();
+
   return reinterpret_cast<CompoundStmt *>(getStoredStmts()[NumCaptures]);
 }
 
diff --git a/clang/lib/AST/Stmt.cpp b/clang/lib/AST/Stmt.cpp
index c0aab4c4db7..80b6be88a3e 100644
--- a/clang/lib/AST/Stmt.cpp
+++ b/clang/lib/AST/Stmt.cpp
@@ -822,7 +822,7 @@ SourceLocation ObjCAtTryStmt::getLocEnd() const {
 CXXTryStmt *CXXTryStmt::Create(const ASTContext &C, SourceLocation tryLoc,
                                Stmt *tryBlock, ArrayRef<Stmt*> handlers) {
   std::size_t Size = sizeof(CXXTryStmt);
-  Size += ((handlers.size() + 1) * sizeof(Stmt));
+  Size += ((handlers.size() + 1) * sizeof(Stmt *));
 
   void *Mem = C.Allocate(Size, llvm::alignOf<CXXTryStmt>());
   return new (Mem) CXXTryStmt(tryLoc, tryBlock, handlers);
@@ -831,7 +831,7 @@ CXXTryStmt *CXXTryStmt::Create(const ASTContext &C, SourceLocation tryLoc,
 CXXTryStmt *CXXTryStmt::Create(const ASTContext &C, EmptyShell Empty,
                                unsigned numHandlers) {
   std::size_t Size = sizeof(CXXTryStmt);
-  Size += ((numHandlers + 1) * sizeof(Stmt));
+  Size += ((numHandlers + 1) * sizeof(Stmt *));
 
   void *Mem = C.Allocate(Size, llvm::alignOf<CXXTryStmt>());
   return new (Mem) CXXTryStmt(Empty, numHandlers);
@@ -2250,4 +2250,3 @@ OMPTeamsDirective *OMPTeamsDirective::CreateEmpty(const ASTContext &C,
       C.Allocate(Size + sizeof(OMPClause *) * NumClauses + sizeof(Stmt *));
   return new (Mem) OMPTeamsDirective(NumClauses);
 }
-
diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp
index d97e40554ef..3d4c4850f60 100644
--- a/clang/lib/CodeGen/CGCleanup.cpp
+++ b/clang/lib/CodeGen/CGCleanup.cpp
@@ -96,6 +96,7 @@ RValue DominatingValue<RValue>::saved_type::restore(CodeGenFunction &CGF) {
 
 /// Push an entry of the given size onto this protected-scope stack.
 char *EHScopeStack::allocate(size_t Size) {
+  Size = llvm::RoundUpToAlignment(Size, ScopeStackAlignment);
   if (!StartOfBuffer) {
     unsigned Capacity = 1024;
     while (Capacity < Size) Capacity *= 2;
@@ -125,6 +126,10 @@ char *EHScopeStack::allocate(size_t Size) {
   return StartOfData;
 }
 
+void EHScopeStack::deallocate(size_t Size) {
+  StartOfData += llvm::RoundUpToAlignment(Size, ScopeStackAlignment);
+}
+
 bool EHScopeStack::containsOnlyLifetimeMarkers(
     EHScopeStack::stable_iterator Old) const {
   for (EHScopeStack::iterator it = begin(); stabilize(it) != Old; it++) {
@@ -166,7 +171,6 @@ EHScopeStack::stable_iterator EHScopeStack::getInnermostActiveEHScope() const {
 
 
 void *EHScopeStack::pushCleanup(CleanupKind Kind, size_t Size) {
-  assert(((Size % sizeof(void*)) == 0) && "cleanup type is misaligned");
   char *Buffer = allocate(EHCleanupScope::getSizeForCleanupSize(Size));
   bool IsNormalCleanup = Kind & NormalCleanup;
   bool IsEHCleanup = Kind & EHCleanup;
@@ -194,7 +198,7 @@ void EHScopeStack::popCleanup() {
   EHCleanupScope &Cleanup = cast<EHCleanupScope>(*begin());
   InnermostNormalCleanup = Cleanup.getEnclosingNormalCleanup();
   InnermostEHScope = Cleanup.getEnclosingEHScope();
-  StartOfData += Cleanup.getAllocatedSize();
+  deallocate(Cleanup.getAllocatedSize());
 
   // Destroy the cleanup.
   Cleanup.Destroy();
@@ -224,7 +228,7 @@ void EHScopeStack::popFilter() {
   assert(!empty() && "popping exception stack when not empty");
 
   EHFilterScope &filter = cast<EHFilterScope>(*begin());
-  StartOfData += EHFilterScope::getSizeForNumFilters(filter.getNumFilters());
+  deallocate(EHFilterScope::getSizeForNumFilters(filter.getNumFilters()));
 
   InnermostEHScope = filter.getEnclosingEHScope();
 }
diff --git a/clang/lib/CodeGen/CGCleanup.h b/clang/lib/CodeGen/CGCleanup.h
index 81c64123dfd..34866d4c47c 100644
--- a/clang/lib/CodeGen/CGCleanup.h
+++ b/clang/lib/CodeGen/CGCleanup.h
@@ -216,7 +216,7 @@ public:
 };
 
 /// A cleanup scope which generates the cleanup blocks lazily.
-class EHCleanupScope : public EHScope {
+class LLVM_ALIGNAS(/*alignof(uint64_t)*/ 8) EHCleanupScope : public EHScope {
   /// The nearest normal cleanup scope enclosing this one.
   EHScopeStack::stable_iterator EnclosingNormal;
 
@@ -396,6 +396,15 @@ public:
     return (Scope->getKind() == Cleanup);
   }
 };
+// NOTE: there's a bunch of different data classes tacked on after an
+// EHCleanupScope. It is asserted (in EHScopeStack::pushCleanup*) that
+// they don't require greater alignment than ScopeStackAlignment. So,
+// EHCleanupScope ought to have alignment equal to that -- not more
+// (would be misaligned by the stack allocator), and not less (would
+// break the appended classes).
+static_assert(llvm::AlignOf<EHCleanupScope>::Alignment ==
+                  EHScopeStack::ScopeStackAlignment,
+              "EHCleanupScope expected alignment");
 
 /// An exceptions scope which filters exceptions thrown through it.
 /// Only exceptions matching the filter types will be permitted to be
@@ -472,27 +481,27 @@ public:
   EHScope &operator*() const { return *get(); }
 
   iterator &operator++() {
+    size_t Size;
     switch (get()->getKind()) {
     case EHScope::Catch:
-      Ptr += EHCatchScope::getSizeForNumHandlers(
-          static_cast<const EHCatchScope*>(get())->getNumHandlers());
+      Size = EHCatchScope::getSizeForNumHandlers(
+          static_cast<const EHCatchScope *>(get())->getNumHandlers());
       break;
 
     case EHScope::Filter:
-      Ptr += EHFilterScope::getSizeForNumFilters(
-          static_cast<const EHFilterScope*>(get())->getNumFilters());
+      Size = EHFilterScope::getSizeForNumFilters(
+          static_cast<const EHFilterScope *>(get())->getNumFilters());
       break;
 
     case EHScope::Cleanup:
-      Ptr += static_cast<const EHCleanupScope*>(get())
-        ->getAllocatedSize();
+      Size = static_cast<const EHCleanupScope *>(get())->getAllocatedSize();
       break;
 
     case EHScope::Terminate:
-      Ptr += EHTerminateScope::getSize();
+      Size = EHTerminateScope::getSize();
       break;
     }
-
+    Ptr += llvm::RoundUpToAlignment(Size, ScopeStackAlignment);
     return *this;
   }
 
@@ -528,7 +537,7 @@ inline void EHScopeStack::popCatch() {
 
   EHCatchScope &scope = cast<EHCatchScope>(*begin());
   InnermostEHScope = scope.getEnclosingEHScope();
-  StartOfData += EHCatchScope::getSizeForNumHandlers(scope.getNumHandlers());
+  deallocate(EHCatchScope::getSizeForNumHandlers(scope.getNumHandlers()));
 }
 
 inline void EHScopeStack::popTerminate() {
@@ -536,7 +545,7 @@ inline void EHScopeStack::popTerminate() {
 
   EHTerminateScope &scope = cast<EHTerminateScope>(*begin());
   InnermostEHScope = scope.getEnclosingEHScope();
-  StartOfData += EHTerminateScope::getSize();
+  deallocate(EHTerminateScope::getSize());
 }
 
 inline EHScopeStack::iterator EHScopeStack::find(stable_iterator sp) const {
diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index c7adccaeeae..371f44fcc95 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -1844,8 +1844,8 @@ void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) {
       MakeAddrLValue(Slot.getAddr(), E->getType(), Slot.getAlignment());
 
   CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
-  for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(),
-                                         e = E->capture_init_end();
+  for (LambdaExpr::const_capture_init_iterator i = E->capture_init_begin(),
+                                               e = E->capture_init_end();
        i != e; ++i, ++CurField) {
     // Emit initialization
     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 7a0b8a35be0..f58c2f440a6 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -2156,8 +2156,8 @@ LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) {
       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();
+  for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(),
+                                                 E = S.capture_init_end();
        I != E; ++I, ++CurField) {
     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
     if (CurField->hasCapturedVLAType()) {
diff --git a/clang/lib/CodeGen/EHScopeStack.h b/clang/lib/CodeGen/EHScopeStack.h
index a7951888c82..7b541b53ea6 100644
--- a/clang/lib/CodeGen/EHScopeStack.h
+++ b/clang/lib/CodeGen/EHScopeStack.h
@@ -96,6 +96,8 @@ enum CleanupKind : unsigned {
 /// and catch blocks.
 class EHScopeStack {
 public:
+  enum { ScopeStackAlignment = llvm::AlignOf<uint64_t>::Alignment };
+
   /// A saved depth on the scope stack.  This is necessary because
   /// pushing scopes onto the stack invalidates iterators.
   class stable_iterator {
@@ -248,6 +250,7 @@ private:
   SmallVector<BranchFixup, 8> BranchFixups;
 
   char *allocate(size_t Size);
+  void deallocate(size_t Size);
 
   void *pushCleanup(CleanupKind K, size_t DataSize);
 
@@ -259,6 +262,8 @@ public:
 
   /// Push a lazily-created cleanup on the stack.
   template <class T, class... As> void pushCleanup(CleanupKind Kind, As... A) {
+    static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment,
+                  "Cleanup's alignment is too large.");
     void *Buffer = pushCleanup(Kind, sizeof(T));
     Cleanup *Obj = new (Buffer) T(A...);
     (void) Obj;
@@ -267,6 +272,8 @@ public:
   /// Push a lazily-created cleanup on the stack. Tuple version.
   template <class T, class... As>
   void pushCleanupTuple(CleanupKind Kind, std::tuple<As...> A) {
+    static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment,
+                  "Cleanup's alignment is too large.");
     void *Buffer = pushCleanup(Kind, sizeof(T));
     Cleanup *Obj = new (Buffer) T(std::move(A));
     (void) Obj;
@@ -287,6 +294,8 @@ public:
   /// stack is modified.
   template <class T, class... As>
   T *pushCleanupWithExtra(CleanupKind Kind, size_t N, As... A) {
+    static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment,
+                  "Cleanup's alignment is too large.");
     void *Buffer = pushCleanup(Kind, sizeof(T) + T::getExtraSize(N));
     return new (Buffer) T(N, A...);
   }
diff --git a/clang/lib/Sema/SemaExceptionSpec.cpp b/clang/lib/Sema/SemaExceptionSpec.cpp
index 094187025df..8a9372336e8 100644
--- a/clang/lib/Sema/SemaExceptionSpec.cpp
+++ b/clang/lib/Sema/SemaExceptionSpec.cpp
@@ -973,8 +973,9 @@ CanThrowResult Sema::canThrow(const Expr *E) {
   case Expr::LambdaExprClass: {
     const LambdaExpr *Lambda = cast<LambdaExpr>(E);
     CanThrowResult CT = CT_Cannot;
-    for (LambdaExpr::capture_init_iterator Cap = Lambda->capture_init_begin(),
-                                        CapEnd = Lambda->capture_init_end();
+    for (LambdaExpr::const_capture_init_iterator
+             Cap = Lambda->capture_init_begin(),
+             CapEnd = Lambda->capture_init_end();
          Cap != CapEnd; ++Cap)
       CT = mergeCanThrow(CT, canThrow(*Cap));
     return CT;