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NeXT: Emit protocol objects lazily. 

- That is, the metadata for a protocol is only emitted if that
   protocol is actually used in the translation unit. This is
   important because Objective-C headers frequently contain a large
   number of protocol definitions, only a few of which will be used in
   any given file.

llvm-svn: 58400
This commit is contained in:
Daniel Dunbar 2008-10-29 22:36:39 +00:00
parent e25142302e
commit c475d4224b
2 changed files with 124 additions and 21 deletions
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97
clang/lib/CodeGen/CGObjCMac.cpp
View File

@ -21,6 +21,7 @@
#include "clang/Basic/LangOptions.h"
#include "llvm/Module.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/Support/IRBuilder.h"
#include "llvm/Target/TargetData.h"
#include <sstream>
@ -219,6 +220,10 @@ private:
/// empty structure whose initializer is filled in when/if defined.
llvm::DenseMap<IdentifierInfo*, llvm::GlobalVariable*> Protocols;
/// DefinedProtocols - Protocols which have actually been
/// defined. We should not need this, see FIXME in GenerateProtocol.
llvm::DenseSet<IdentifierInfo*> DefinedProtocols;
/// DefinedClasses - List of defined classes.
std::vector<llvm::GlobalValue*> DefinedClasses;
@ -316,6 +321,17 @@ private:
ObjCPropertyDecl * const *begin,
ObjCPropertyDecl * const *end);
/// GetOrEmitProtocol - Get the protocol object for the given
/// declaration, emitting it if necessary. The return value has type
/// ProtocolPtrTy.
llvm::Constant *GetOrEmitProtocol(const ObjCProtocolDecl *PD);
/// GetOrEmitProtocolRef - Get a forward reference to the protocol
/// object for the given declaration, emitting it if needed. These
/// forward references will be filled in with empty bodies if no
/// definition is seen. The return value has type ProtocolPtrTy.
llvm::Constant *GetOrEmitProtocolRef(const ObjCProtocolDecl *PD);
/// EmitProtocolExtension - Generate the protocol extension
/// structure used to store optional instance and class methods, and
/// protocol properties. The return value has type
@ -337,8 +353,8 @@ private:
/// GetProtocolRef - Return a reference to the internal protocol
/// description, creating an empty one if it has not been
/// defined. The return value has type pointer-to ProtocolTy.
llvm::GlobalVariable *GetProtocolRef(const ObjCProtocolDecl *PD);
/// defined. The return value has type ProtocolPtrTy.
llvm::Constant *GetProtocolRef(const ObjCProtocolDecl *PD);
/// GetClassName - Return a unique constant for the given selector's
/// name. The return value has type char *.
@ -506,7 +522,7 @@ CGObjCMac::GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
// and ObjCTypes types.
const llvm::Type *ClassTy =
CGM.getTypes().ConvertType(CGF.getContext().getObjCClassType());
Target = CGF.Builder.CreateBitCast(Target, ClassTy);
Target = CGF.Builder.CreateBitCast(Target, ClassTy);
CGF.Builder.CreateStore(Target,
CGF.Builder.CreateStructGEP(ObjCSuper, 1));
@ -572,6 +588,25 @@ llvm::Value *CGObjCMac::GenerateProtocolRef(llvm::IRBuilder<> &Builder,
ObjCTypes.ExternalProtocolPtrTy);
}
void CGObjCMac::GenerateProtocol(const ObjCProtocolDecl *PD) {
// FIXME: We shouldn't need this, the protocol decl should contain
// enough information to tell us whether this was a declaration or a
// definition.
DefinedProtocols.insert(PD->getIdentifier());
// If we have generated a forward reference to this protocol, emit
// it now. Otherwise do nothing, the protocol objects are lazily
// emitted.
if (Protocols.count(PD->getIdentifier()))
GetOrEmitProtocol(PD);
}
llvm::Constant *CGObjCMac::GetProtocolRef(const ObjCProtocolDecl *PD) {
if (DefinedProtocols.count(PD->getIdentifier()))
return GetOrEmitProtocol(PD);
return GetOrEmitProtocolRef(PD);
}
/*
// APPLE LOCAL radar 4585769 - Objective-C 1.0 extensions
struct _objc_protocol {
@ -584,7 +619,13 @@ llvm::Value *CGObjCMac::GenerateProtocolRef(llvm::IRBuilder<> &Builder,
See EmitProtocolExtension().
*/
void CGObjCMac::GenerateProtocol(const ObjCProtocolDecl *PD) {
llvm::Constant *CGObjCMac::GetOrEmitProtocol(const ObjCProtocolDecl *PD) {
llvm::GlobalVariable *&Entry = Protocols[PD->getIdentifier()];
// Early exit if a defining object has already been generated.
if (Entry && Entry->hasInitializer())
return Entry;
// FIXME: I don't understand why gcc generates this, or where it is
// resolved. Investigate. Its also wasteful to look this up over and
// over.
@ -637,9 +678,9 @@ void CGObjCMac::GenerateProtocol(const ObjCProtocolDecl *PD) {
llvm::Constant *Init = llvm::ConstantStruct::get(ObjCTypes.ProtocolTy,
Values);
llvm::GlobalVariable *&Entry = Protocols[PD->getIdentifier()];
if (Entry) {
// Already created, just update the initializer
// Already created, fix the linkage and update the initializer.
Entry->setLinkage(llvm::GlobalValue::InternalLinkage);
Entry->setInitializer(Init);
} else {
Entry =
@ -653,25 +694,21 @@ void CGObjCMac::GenerateProtocol(const ObjCProtocolDecl *PD) {
// FIXME: Is this necessary? Why only for protocol?
Entry->setAlignment(4);
}
return Entry;
}
llvm::GlobalVariable *CGObjCMac::GetProtocolRef(const ObjCProtocolDecl *PD) {
llvm::Constant *CGObjCMac::GetOrEmitProtocolRef(const ObjCProtocolDecl *PD) {
llvm::GlobalVariable *&Entry = Protocols[PD->getIdentifier()];
if (!Entry) {
std::vector<llvm::Constant*> Values(5);
Values[0] = llvm::Constant::getNullValue(ObjCTypes.ProtocolExtensionPtrTy);
Values[1] = GetClassName(PD->getIdentifier());
Values[2] = llvm::Constant::getNullValue(ObjCTypes.ProtocolListPtrTy);
Values[3] = Values[4] =
llvm::Constant::getNullValue(ObjCTypes.MethodDescriptionListPtrTy);
llvm::Constant *Init = llvm::ConstantStruct::get(ObjCTypes.ProtocolTy,
Values);
// We use the initializer as a marker of whether this is a forward
// reference or not. At module finalization we add the empty
// contents for protocols which were referenced but never defined.
Entry =
new llvm::GlobalVariable(ObjCTypes.ProtocolTy, false,
llvm::GlobalValue::InternalLinkage,
Init,
llvm::GlobalValue::ExternalLinkage,
0,
std::string("\01L_OBJC_PROTOCOL_")+PD->getName(),
&CGM.getModule());
Entry->setSection("__OBJC,__protocol,regular,no_dead_strip");
@ -1510,7 +1547,8 @@ void CGObjCMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
// Allocate memory for the exception data and rethrow pointer.
llvm::Value *ExceptionData = CGF.CreateTempAlloca(ObjCTypes.ExceptionDataTy,
"exceptiondata.ptr");
llvm::Value *RethrowPtr = CGF.CreateTempAlloca(ObjCTypes.ObjectPtrTy, "_rethrow");
llvm::Value *RethrowPtr = CGF.CreateTempAlloca(ObjCTypes.ObjectPtrTy,
"_rethrow");
// Enter a new try block and call setjmp.
CGF.Builder.CreateCall(ObjCTypes.ExceptionTryEnterFn, ExceptionData);
@ -1988,8 +2026,25 @@ void CGObjCMac::GetNameForMethod(const ObjCMethodDecl *D,
void CGObjCMac::FinishModule() {
EmitModuleInfo();
std::vector<llvm::Constant*> Used;
// Emit the dummy bodies for any protocols which were referenced but
// never defined.
for (llvm::DenseMap<IdentifierInfo*, llvm::GlobalVariable*>::iterator
i = Protocols.begin(), e = Protocols.end(); i != e; ++i) {
if (i->second->hasInitializer())
continue;
std::vector<llvm::Constant*> Values(5);
Values[0] = llvm::Constant::getNullValue(ObjCTypes.ProtocolExtensionPtrTy);
Values[1] = GetClassName(i->first);
Values[2] = llvm::Constant::getNullValue(ObjCTypes.ProtocolListPtrTy);
Values[3] = Values[4] =
llvm::Constant::getNullValue(ObjCTypes.MethodDescriptionListPtrTy);
i->second->setLinkage(llvm::GlobalValue::InternalLinkage);
i->second->setInitializer(llvm::ConstantStruct::get(ObjCTypes.ProtocolTy,
Values));
}
std::vector<llvm::Constant*> Used;
for (std::vector<llvm::GlobalVariable*>::iterator i = UsedGlobals.begin(),
e = UsedGlobals.end(); i != e; ++i) {
Used.push_back(llvm::ConstantExpr::getBitCast(*i, ObjCTypes.Int8PtrTy));
@ -2086,7 +2141,7 @@ ObjCTypesHelper::ObjCTypesHelper(CodeGen::CodeGenModule &cgm)
ProtocolExtensionTy);
ProtocolExtensionPtrTy = llvm::PointerType::getUnqual(ProtocolExtensionTy);
// Handle recursive construction of Protocl and ProtocolList types
// Handle recursive construction of Protocol and ProtocolList types
llvm::PATypeHolder ProtocolTyHolder = llvm::OpaqueType::get();
llvm::PATypeHolder ProtocolListTyHolder = llvm::OpaqueType::get();

48
clang/test/CodeGenObjC/protocols-lazy.m Normal file
View File

@ -0,0 +1,48 @@
// RUN: clang -emit-llvm -o %t %s &&
// RUNX: llvm-gcc -S -emit-llvm -o %t %s &&
// No object generated
// RUN: grep OBJC_PROTOCOL_P0 %t | count 0 &&
@protocol P0;
// No object generated
// RUN: grep OBJC_PROTOCOL_P1 %t | count 0 &&
@protocol P1 -im1; @end
// Definition triggered by protocol reference.
// RUN: grep OBJC_PROTOCOL_P2 %t | count 3 &&
// RUN: grep OBJC_PROTOCOL_INSTANCE_METHODS_P2 %t | count 3 &&
@protocol P2 -im1; @end
void f0() { id x = @protocol(P2); }
// Forward definition triggered by protocol reference.
// RUN: grep OBJC_PROTOCOL_P3 %t | count 3 &&
// RUN: grep OBJC_PROTOCOL_INSTANCE_METHODS_P3 %t | count 0 &&
@protocol P3;
void f1() { id x = @protocol(P3); }
// Definition triggered by class reference.
// RUN: grep OBJC_PROTOCOL_P4 %t | count 3 &&
// RUN: grep OBJC_PROTOCOL_INSTANCE_METHODS_P4 %t | count 3 &&
@protocol P4 -im1; @end
@interface I0<P4> @end
@implementation I0 -im1 {}; @end
// Definition following forward reference.
// RUN: grep OBJC_PROTOCOL_P5 %t | count 3 &&
// RUN: grep OBJC_PROTOCOL_INSTANCE_METHODS_P5 %t | count 3 &&
@protocol P5;
void f2() { id x = @protocol(P5); } // This generates a forward
// reference, which has to be
// updated on the next line.
@protocol P5 -im1; @end
// Protocol reference following definition.
// RUN: grep OBJC_PROTOCOL_P6 %t | count 4 &&
// RUN: grep OBJC_PROTOCOL_INSTANCE_METHODS_P6 %t | count 3 &&
@protocol P6 -im1; @end
@interface I1<P6> @end
@implementation I1 -im1 {}; @end
void f3() { id x = @protocol(P6); }
// RUN: true