r233911 - Replace custom alignment enforcement with LLVM_ALIGNAS.
Benjamin Kramer
benny.kra at googlemail.com
Thu Apr 2 05:25:07 PDT 2015
Author: d0k
Date: Thu Apr 2 07:25:07 2015
New Revision: 233911
URL: http://llvm.org/viewvc/llvm-project?rev=233911&view=rev
Log:
Replace custom alignment enforcement with LLVM_ALIGNAS.
This isn't perfect as it still assumes sizeof(void*) == alignof(void*),
but we can fix that when compiler support gets better.
Shrinks some Stmts that happen to inherit from Stmt and have a
SourceLocation as the first member (64 bit archs only).
Modified:
cfe/trunk/include/clang/AST/DeclGroup.h
cfe/trunk/include/clang/AST/DeclTemplate.h
cfe/trunk/include/clang/AST/Stmt.h
cfe/trunk/include/clang/Basic/SourceManager.h
cfe/trunk/lib/AST/Decl.cpp
cfe/trunk/lib/AST/DeclGroup.cpp
Modified: cfe/trunk/include/clang/AST/DeclGroup.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclGroup.h?rev=233911&r1=233910&r2=233911&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/DeclGroup.h (original)
+++ cfe/trunk/include/clang/AST/DeclGroup.h Thu Apr 2 07:25:07 2015
@@ -14,6 +14,7 @@
#ifndef LLVM_CLANG_AST_DECLGROUP_H
#define LLVM_CLANG_AST_DECLGROUP_H
+#include "llvm/Support/Compiler.h"
#include "llvm/Support/DataTypes.h"
#include <cassert>
@@ -24,13 +25,9 @@ class Decl;
class DeclGroup;
class DeclGroupIterator;
-class DeclGroup {
+class LLVM_ALIGNAS(sizeof(void *)) DeclGroup {
// FIXME: Include a TypeSpecifier object.
- union {
- unsigned NumDecls;
-
- Decl *Aligner;
- };
+ unsigned NumDecls;
private:
DeclGroup() : NumDecls(0) {}
Modified: cfe/trunk/include/clang/AST/DeclTemplate.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclTemplate.h?rev=233911&r1=233910&r2=233911&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/DeclTemplate.h (original)
+++ cfe/trunk/include/clang/AST/DeclTemplate.h Thu Apr 2 07:25:07 2015
@@ -460,21 +460,12 @@ public:
/// friend void foo<>(T);
/// };
/// \endcode
-class DependentFunctionTemplateSpecializationInfo {
- struct CA {
- /// The number of potential template candidates.
- unsigned NumTemplates;
-
- /// The number of template arguments.
- unsigned NumArgs;
- };
-
- union {
- // Force sizeof to be a multiple of sizeof(void*) so that the
- // trailing data is aligned.
- void *Aligner;
- struct CA d;
- };
+class LLVM_ALIGNAS(sizeof(void *)) DependentFunctionTemplateSpecializationInfo {
+ /// The number of potential template candidates.
+ unsigned NumTemplates;
+
+ /// The number of template arguments.
+ unsigned NumArgs;
/// The locations of the left and right angle brackets.
SourceRange AngleLocs;
@@ -490,9 +481,7 @@ public:
/// \brief Returns the number of function templates that this might
/// be a specialization of.
- unsigned getNumTemplates() const {
- return d.NumTemplates;
- }
+ unsigned getNumTemplates() const { return NumTemplates; }
/// \brief Returns the i'th template candidate.
FunctionTemplateDecl *getTemplate(unsigned I) const {
@@ -507,9 +496,7 @@ public:
}
/// \brief Returns the number of explicit template arguments that were given.
- unsigned getNumTemplateArgs() const {
- return d.NumArgs;
- }
+ unsigned getNumTemplateArgs() const { return NumArgs; }
/// \brief Returns the nth template argument.
const TemplateArgumentLoc &getTemplateArg(unsigned I) const {
Modified: cfe/trunk/include/clang/AST/Stmt.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Stmt.h?rev=233911&r1=233910&r2=233911&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Stmt.h (original)
+++ cfe/trunk/include/clang/AST/Stmt.h Thu Apr 2 07:25:07 2015
@@ -101,7 +101,7 @@ namespace clang {
/// Stmt - This represents one statement.
///
-class Stmt {
+class LLVM_ALIGNAS(sizeof(void *)) Stmt {
public:
enum StmtClass {
NoStmtClass = 0,
@@ -287,9 +287,6 @@ protected:
};
union {
- // FIXME: this is wasteful on 64-bit platforms.
- void *Aligner;
-
StmtBitfields StmtBits;
CompoundStmtBitfields CompoundStmtBits;
ExprBitfields ExprBits;
@@ -341,13 +338,12 @@ private:
protected:
/// \brief Construct an empty statement.
- explicit Stmt(StmtClass SC, EmptyShell) {
- StmtBits.sClass = SC;
- if (StatisticsEnabled) Stmt::addStmtClass(SC);
- }
+ explicit Stmt(StmtClass SC, EmptyShell) : Stmt(SC) {}
public:
Stmt(StmtClass SC) {
+ static_assert(sizeof(*this) % llvm::AlignOf<void *>::Alignment == 0,
+ "Insufficient alignment!");
StmtBits.sClass = SC;
if (StatisticsEnabled) Stmt::addStmtClass(SC);
}
Modified: cfe/trunk/include/clang/Basic/SourceManager.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/SourceManager.h?rev=233911&r1=233910&r2=233911&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/SourceManager.h (original)
+++ cfe/trunk/include/clang/Basic/SourceManager.h Thu Apr 2 07:25:07 2015
@@ -82,7 +82,7 @@ namespace SrcMgr {
/// \brief One instance of this struct is kept for every file loaded or used.
///
/// This object owns the MemoryBuffer object.
- class ContentCache {
+ class LLVM_ALIGNAS(8) ContentCache {
enum CCFlags {
/// \brief Whether the buffer is invalid.
InvalidFlag = 0x01,
@@ -90,15 +90,6 @@ namespace SrcMgr {
DoNotFreeFlag = 0x02
};
- // Note that the first member of this class is an aligned character buffer
- // to ensure that this class has an alignment of 8 bytes. This wastes
- // 8 bytes for every ContentCache object, but each of these corresponds to
- // a file loaded into memory, so the 8 bytes doesn't seem terribly
- // important. It is quite awkward to fit this aligner into any other part
- // of the class due to the lack of portable ways to combine it with other
- // members.
- llvm::AlignedCharArray<8, 1> NonceAligner;
-
/// \brief The actual buffer containing the characters from the input
/// file.
///
@@ -142,14 +133,9 @@ namespace SrcMgr {
/// \brief True if this content cache was initially created for a source
/// file considered as a system one.
unsigned IsSystemFile : 1;
-
- ContentCache(const FileEntry *Ent = nullptr)
- : Buffer(nullptr, false), OrigEntry(Ent), ContentsEntry(Ent),
- SourceLineCache(nullptr), NumLines(0), BufferOverridden(false),
- IsSystemFile(false) {
- (void)NonceAligner; // Silence warnings about unused member.
- }
-
+
+ ContentCache(const FileEntry *Ent = nullptr) : ContentCache(Ent, Ent) {}
+
ContentCache(const FileEntry *Ent, const FileEntry *contentEnt)
: Buffer(nullptr, false), OrigEntry(Ent), ContentsEntry(contentEnt),
SourceLineCache(nullptr), NumLines(0), BufferOverridden(false),
Modified: cfe/trunk/lib/AST/Decl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Decl.cpp?rev=233911&r1=233910&r2=233911&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Decl.cpp (original)
+++ cfe/trunk/lib/AST/Decl.cpp Thu Apr 2 07:25:07 2015
@@ -3103,10 +3103,10 @@ FunctionDecl::setDependentTemplateSpecia
DependentFunctionTemplateSpecializationInfo::
DependentFunctionTemplateSpecializationInfo(const UnresolvedSetImpl &Ts,
const TemplateArgumentListInfo &TArgs)
- : AngleLocs(TArgs.getLAngleLoc(), TArgs.getRAngleLoc()) {
-
- d.NumTemplates = Ts.size();
- d.NumArgs = TArgs.size();
+ : NumTemplates(Ts.size()), NumArgs(TArgs.size()),
+ AngleLocs(TArgs.getLAngleLoc(), TArgs.getRAngleLoc()) {
+ static_assert(sizeof(*this) % llvm::AlignOf<void *>::Alignment == 0,
+ "Trailing data is unaligned!");
FunctionTemplateDecl **TsArray =
const_cast<FunctionTemplateDecl**>(getTemplates());
Modified: cfe/trunk/lib/AST/DeclGroup.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/DeclGroup.cpp?rev=233911&r1=233910&r2=233911&view=diff
==============================================================================
--- cfe/trunk/lib/AST/DeclGroup.cpp (original)
+++ cfe/trunk/lib/AST/DeclGroup.cpp Thu Apr 2 07:25:07 2015
@@ -18,6 +18,8 @@
using namespace clang;
DeclGroup* DeclGroup::Create(ASTContext &C, Decl **Decls, unsigned NumDecls) {
+ static_assert(sizeof(DeclGroup) % llvm::AlignOf<void *>::Alignment == 0,
+ "Trailing data is unaligned!");
assert(NumDecls > 1 && "Invalid DeclGroup");
unsigned Size = sizeof(DeclGroup) + sizeof(Decl*) * NumDecls;
void* Mem = C.Allocate(Size, llvm::AlignOf<DeclGroup>::Alignment);
More information about the cfe-commits
mailing list