[llvm-commits] [llvm] r72700 - in /llvm/trunk/tools/lto: LTOModule.cpp LTOModule.h
Nick Lewycky
nlewycky at google.com
Mon Jun 1 14:11:28 PDT 2009
2009/6/1 Nick Kledzik <kledzik at apple.com>
> Author: kledzik
> Date: Mon Jun 1 15:33:09 2009
> New Revision: 72700
>
> URL: http://llvm.org/viewvc/llvm-project?rev=72700&view=rev
> Log:
> <rdar://problem/6927148> libLTO needs to handle i386 magic objc class
> symbols
> Parse __OBJC data structures and synthesize magic .objc_ symbols.
> Also, alter mangler so that objc method names are readable.
Hi Nick, could you please elaborate on why exactly libLTO needs to change?
While I don't doubt that this fixes a bug, I can't see how this
language-specific logic could possibly belong in libLTO.
>
>
> Modified:
> llvm/trunk/tools/lto/LTOModule.cpp
> llvm/trunk/tools/lto/LTOModule.h
>
> Modified: llvm/trunk/tools/lto/LTOModule.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/lto/LTOModule.cpp?rev=72700&r1=72699&r2=72700&view=diff
>
>
> ==============================================================================
> --- llvm/trunk/tools/lto/LTOModule.cpp (original)
> +++ llvm/trunk/tools/lto/LTOModule.cpp Mon Jun 1 15:33:09 2009
> @@ -14,6 +14,7 @@
>
> #include "LTOModule.h"
>
> +#include "llvm/Constants.h"
> #include "llvm/Module.h"
> #include "llvm/ModuleProvider.h"
> #include "llvm/ADT/OwningPtr.h"
> @@ -176,11 +177,123 @@
> }
> }
>
> -void LTOModule::addDefinedDataSymbol(GlobalValue* v, Mangler &mangler)
> +// get string that data pointer points to
> +bool LTOModule::objcClassNameFromExpression(Constant* c, std::string&
> name)
> +{
> + if (ConstantExpr* ce = dyn_cast<ConstantExpr>(c)) {
Is there any reason not to just assert on this? Will it ever really be
called on constants that aren't known to be objcClassNames?
>
> + Constant* op = ce->getOperand(0);
> + if (GlobalVariable* gvn = dyn_cast<GlobalVariable>(op)) {
> + Constant* cn = gvn->getInitializer();
> + if (ConstantArray* ca = dyn_cast<ConstantArray>(cn)) {
> + if ( ca->isCString() ) {
> + name = ".objc_class_name_" + ca->getAsString();
> + return true;
> + }
> + }
> + }
> + }
> + return false;
> +}
> +
> +// parse i386/ppc ObjC class data structure
> +void LTOModule::addObjCClass(GlobalVariable* clgv)
> +{
> + if (ConstantStruct* c =
> dyn_cast<ConstantStruct>(clgv->getInitializer())) {
Here again, perhaps it should just assert that this is true?
>
> + // second slot in __OBJC,__class is pointer to superclass name
> + std::string superclassName;
> + if ( objcClassNameFromExpression(c->getOperand(1), superclassName)
> ) {
> + NameAndAttributes info;
> + if ( _undefines.find(superclassName.c_str()) ==
> _undefines.end() ) {
> + const char* symbolName = ::strdup(superclassName.c_str());
> + info.name = ::strdup(symbolName);
> + info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED;
> + // string is owned by _undefines
> + _undefines[info.name] = info;
Perhaps the non-libLTO side of the Apple linker should ignore symbols it
knows are objC specific? Or perhaps you could run a domain-specific LLVM
pass which would delete these globals as needed? If somehow you need them to
exist but still be marked undefined, perhaps libLTO should expose an
interface for marking symbols undefined instead of an interface specific to
Apple's implementation of the objC language?
It just seems like this is breaking encapsulation, the linker has linking
rules that don't much care what the source language was.
Nick
>
> + }
> + }
> + // third slot in __OBJC,__class is pointer to class name
> + std::string className;
> + if ( objcClassNameFromExpression(c->getOperand(2), className) ) {
> + const char* symbolName = ::strdup(className.c_str());
> + NameAndAttributes info;
> + info.name = symbolName;
> + info.attributes = (lto_symbol_attributes)
> + (LTO_SYMBOL_PERMISSIONS_DATA |
> + LTO_SYMBOL_DEFINITION_REGULAR |
> + LTO_SYMBOL_SCOPE_DEFAULT);
> + _symbols.push_back(info);
> + _defines[info.name] = 1;
> + }
> + }
> +}
> +
> +
> +// parse i386/ppc ObjC category data structure
> +void LTOModule::addObjCCategory(GlobalVariable* clgv)
> +{
> + if (ConstantStruct* c =
> dyn_cast<ConstantStruct>(clgv->getInitializer())) {
> + // second slot in __OBJC,__category is pointer to target class
> name
> + std::string targetclassName;
> + if ( objcClassNameFromExpression(c->getOperand(1),
> targetclassName) ) {
> + NameAndAttributes info;
> + if ( _undefines.find(targetclassName.c_str()) ==
> _undefines.end() ){
> + const char* symbolName =
> ::strdup(targetclassName.c_str());
> + info.name = ::strdup(symbolName);
> + info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED;
> + // string is owned by _undefines
> + _undefines[info.name] = info;
> + }
> + }
> + }
> +}
> +
> +
> +// parse i386/ppc ObjC class list data structure
> +void LTOModule::addObjCClassRef(GlobalVariable* clgv)
> +{
> + std::string targetclassName;
> + if ( objcClassNameFromExpression(clgv->getInitializer(),
> targetclassName) ){
> + NameAndAttributes info;
> + if ( _undefines.find(targetclassName.c_str()) == _undefines.end()
> ) {
> + const char* symbolName = ::strdup(targetclassName.c_str());
> + info.name = ::strdup(symbolName);
> + info.attributes = LTO_SYMBOL_DEFINITION_UNDEFINED;
> + // string is owned by _undefines
> + _undefines[info.name] = info;
> + }
> + }
> +}
> +
> +
> +void LTOModule::addDefinedDataSymbol(GlobalValue* v, Mangler& mangler)
> {
> // add to list of defined symbols
> addDefinedSymbol(v, mangler, false);
>
> + // special case i386/ppc ObjC data structures in magic sections
> + if ( v->hasSection() ) {
> + // special case if this data blob is an ObjC class definition
> + if ( v->getSection().compare(0, 15, "__OBJC,__class,") == 0 ) {
> + if (GlobalVariable* gv = dyn_cast<GlobalVariable>(v)) {
> + addObjCClass(gv);
> + }
> + }
> +
> + // special case if this data blob is an ObjC category definition
> + else if ( v->getSection().compare(0, 18, "__OBJC,__category,") ==
> 0 ) {
> + if (GlobalVariable* gv = dyn_cast<GlobalVariable>(v)) {
> + addObjCCategory(gv);
> + }
> + }
> +
> + // special case if this data blob is the list of referenced
> classes
> + else if ( v->getSection().compare(0, 18, "__OBJC,__cls_refs,") ==
> 0 ) {
> + if (GlobalVariable* gv = dyn_cast<GlobalVariable>(v)) {
> + addObjCClassRef(gv);
> + }
> + }
> + }
> +
> // add external symbols referenced by this data.
> for (unsigned count = 0, total = v->getNumOperands();
> count != total; ++count) {
> @@ -192,9 +305,13 @@
> void LTOModule::addDefinedSymbol(GlobalValue* def, Mangler &mangler,
> bool isFunction)
> {
> + // ignore all llvm.* symbols
> + if ( strncmp(def->getNameStart(), "llvm.", 5) == 0 )
> + return;
> +
> // string is owned by _defines
> const char* symbolName = ::strdup(mangler.getValueName(def).c_str());
> -
> +
> // set alignment part log2() can have rounding errors
> uint32_t align = def->getAlignment();
> uint32_t attr = align ? CountTrailingZeros_32(def->getAlignment()) : 0;
> @@ -241,25 +358,28 @@
> }
>
> void LTOModule::addAsmGlobalSymbol(const char *name) {
> - // string is owned by _defines
> - const char *symbolName = ::strdup(name);
> - uint32_t attr = LTO_SYMBOL_DEFINITION_REGULAR;
> - attr |= LTO_SYMBOL_SCOPE_DEFAULT;
> -
> - // add to table of symbols
> - NameAndAttributes info;
> - info.name = symbolName;
> - info.attributes = (lto_symbol_attributes)attr;
> - _symbols.push_back(info);
> - _defines[info.name] = 1;
> + // only add new define if not already defined
> + if ( _defines.count(name, &name[strlen(name)+1]) == 0 )
> + return;
> +
> + // string is owned by _defines
> + const char *symbolName = ::strdup(name);
> + uint32_t attr = LTO_SYMBOL_DEFINITION_REGULAR;
> + attr |= LTO_SYMBOL_SCOPE_DEFAULT;
> + NameAndAttributes info;
> + info.name = symbolName;
> + info.attributes = (lto_symbol_attributes)attr;
> + _symbols.push_back(info);
> + _defines[info.name] = 1;
> }
>
> void LTOModule::addPotentialUndefinedSymbol(GlobalValue* decl, Mangler
> &mangler)
> {
> - const char* name = mangler.getValueName(decl).c_str();
> // ignore all llvm.* symbols
> - if ( strncmp(name, "llvm.", 5) == 0 )
> - return;
> + if ( strncmp(decl->getNameStart(), "llvm.", 5) == 0 )
> + return;
> +
> + const char* name = mangler.getValueName(decl).c_str();
>
> // we already have the symbol
> if (_undefines.find(name) != _undefines.end())
> @@ -306,6 +426,14 @@
>
> // Use mangler to add GlobalPrefix to names to match linker names.
> Mangler mangler(*_module,
> _target->getTargetAsmInfo()->getGlobalPrefix());
> + // add chars used in ObjC method names so method names aren't
> mangled
> + mangler.markCharAcceptable('[');
> + mangler.markCharAcceptable(']');
> + mangler.markCharAcceptable('(');
> + mangler.markCharAcceptable(')');
> + mangler.markCharAcceptable('-');
> + mangler.markCharAcceptable('+');
> + mangler.markCharAcceptable(' ');
>
> // add functions
> for (Module::iterator f = _module->begin(); f != _module->end();
> ++f) {
>
> Modified: llvm/trunk/tools/lto/LTOModule.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/lto/LTOModule.h?rev=72700&r1=72699&r2=72700&view=diff
>
>
> ==============================================================================
> --- llvm/trunk/tools/lto/LTOModule.h (original)
> +++ llvm/trunk/tools/lto/LTOModule.h Mon Jun 1 15:33:09 2009
> @@ -77,13 +77,19 @@
> void addDefinedDataSymbol(llvm::GlobalValue* v,
> llvm::Mangler
> &mangler);
> void addAsmGlobalSymbol(const char *);
> + void addObjCClass(llvm::GlobalVariable* clgv);
> + void addObjCCategory(llvm::GlobalVariable* clgv);
> + void addObjCClassRef(llvm::GlobalVariable* clgv);
> + bool objcClassNameFromExpression(llvm::Constant* c,
> + std::string& name);
> +
> static bool isTargetMatch(llvm::MemoryBuffer* memBuffer,
> const char*
> triplePrefix);
> -
> +
> static LTOModule* makeLTOModule(llvm::MemoryBuffer* buffer,
> std::string&
> errMsg);
> static llvm::MemoryBuffer* makeBuffer(const void* mem, size_t length);
> -
> +
> typedef llvm::StringMap<uint8_t> StringSet;
>
> struct NameAndAttributes {
>
>
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