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//===- XCore.cpp ----------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "ABIInfoImpl.h"
#include "TargetInfo.h"
using namespace clang;
using namespace clang::CodeGen;
//===----------------------------------------------------------------------===//
// XCore ABI Implementation
//===----------------------------------------------------------------------===//
namespace {
/// A SmallStringEnc instance is used to build up the TypeString by passing
/// it by reference between functions that append to it.
typedef llvm::SmallString<128> SmallStringEnc;
/// TypeStringCache caches the meta encodings of Types.
///
/// The reason for caching TypeStrings is two fold:
/// 1. To cache a type's encoding for later uses;
/// 2. As a means to break recursive member type inclusion.
///
/// A cache Entry can have a Status of:
/// NonRecursive: The type encoding is not recursive;
/// Recursive: The type encoding is recursive;
/// Incomplete: An incomplete TypeString;
/// IncompleteUsed: An incomplete TypeString that has been used in a
/// Recursive type encoding.
///
/// A NonRecursive entry will have all of its sub-members expanded as fully
/// as possible. Whilst it may contain types which are recursive, the type
/// itself is not recursive and thus its encoding may be safely used whenever
/// the type is encountered.
///
/// A Recursive entry will have all of its sub-members expanded as fully as
/// possible. The type itself is recursive and it may contain other types which
/// are recursive. The Recursive encoding must not be used during the expansion
/// of a recursive type's recursive branch. For simplicity the code uses
/// IncompleteCount to reject all usage of Recursive encodings for member types.
///
/// An Incomplete entry is always a RecordType and only encodes its
/// identifier e.g. "s(S){}". Incomplete 'StubEnc' entries are ephemeral and
/// are placed into the cache during type expansion as a means to identify and
/// handle recursive inclusion of types as sub-members. If there is recursion
/// the entry becomes IncompleteUsed.
///
/// During the expansion of a RecordType's members:
///
/// If the cache contains a NonRecursive encoding for the member type, the
/// cached encoding is used;
///
/// If the cache contains a Recursive encoding for the member type, the
/// cached encoding is 'Swapped' out, as it may be incorrect, and...
///
/// If the member is a RecordType, an Incomplete encoding is placed into the
/// cache to break potential recursive inclusion of itself as a sub-member;
///
/// Once a member RecordType has been expanded, its temporary incomplete
/// entry is removed from the cache. If a Recursive encoding was swapped out
/// it is swapped back in;
///
/// If an incomplete entry is used to expand a sub-member, the incomplete
/// entry is marked as IncompleteUsed. The cache keeps count of how many
/// IncompleteUsed entries it currently contains in IncompleteUsedCount;
///
/// If a member's encoding is found to be a NonRecursive or Recursive viz:
/// IncompleteUsedCount==0, the member's encoding is added to the cache.
/// Else the member is part of a recursive type and thus the recursion has
/// been exited too soon for the encoding to be correct for the member.
///
class TypeStringCache {
enum Status {NonRecursive, Recursive, Incomplete, IncompleteUsed};
struct Entry {
std::string Str; // The encoded TypeString for the type.
enum Status State; // Information about the encoding in 'Str'.
std::string Swapped; // A temporary place holder for a Recursive encoding
// during the expansion of RecordType's members.
};
std::map<const IdentifierInfo *, struct Entry> Map;
unsigned IncompleteCount; // Number of Incomplete entries in the Map.
unsigned IncompleteUsedCount; // Number of IncompleteUsed entries in the Map.
public:
TypeStringCache() : IncompleteCount(0), IncompleteUsedCount(0) {}
void addIncomplete(const IdentifierInfo *ID, std::string StubEnc);
bool removeIncomplete(const IdentifierInfo *ID);
void addIfComplete(const IdentifierInfo *ID, StringRef Str,
bool IsRecursive);
StringRef lookupStr(const IdentifierInfo *ID);
};
/// TypeString encodings for enum & union fields must be order.
/// FieldEncoding is a helper for this ordering process.
class FieldEncoding {
bool HasName;
std::string Enc;
public:
FieldEncoding(bool b, SmallStringEnc &e) : HasName(b), Enc(e.c_str()) {}
StringRef str() { return Enc; }
bool operator<(const FieldEncoding &rhs) const {
if (HasName != rhs.HasName) return HasName;
return Enc < rhs.Enc;
}
};
class XCoreABIInfo : public DefaultABIInfo {
public:
XCoreABIInfo(CodeGen::CodeGenTypes &CGT) : DefaultABIInfo(CGT) {}
Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType Ty) const override;
};
class XCoreTargetCodeGenInfo : public TargetCodeGenInfo {
mutable TypeStringCache TSC;
void emitTargetMD(const Decl *D, llvm::GlobalValue *GV,
const CodeGen::CodeGenModule &M) const;
public:
XCoreTargetCodeGenInfo(CodeGenTypes &CGT)
: TargetCodeGenInfo(std::make_unique<XCoreABIInfo>(CGT)) {}
void emitTargetMetadata(CodeGen::CodeGenModule &CGM,
const llvm::MapVector<GlobalDecl, StringRef>
&MangledDeclNames) const override;
};
} // End anonymous namespace.
// TODO: this implementation is likely now redundant with the default
// EmitVAArg.
Address XCoreABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType Ty) const {
CGBuilderTy &Builder = CGF.Builder;
// Get the VAList.
CharUnits SlotSize = CharUnits::fromQuantity(4);
Address AP = Address(Builder.CreateLoad(VAListAddr),
getVAListElementType(CGF), SlotSize);
// Handle the argument.
ABIArgInfo AI = classifyArgumentType(Ty);
CharUnits TypeAlign = getContext().getTypeAlignInChars(Ty);
llvm::Type *ArgTy = CGT.ConvertType(Ty);
if (AI.canHaveCoerceToType() && !AI.getCoerceToType())
AI.setCoerceToType(ArgTy);
llvm::Type *ArgPtrTy = llvm::PointerType::getUnqual(ArgTy);
Address Val = Address::invalid();
CharUnits ArgSize = CharUnits::Zero();
switch (AI.getKind()) {
case ABIArgInfo::Expand:
case ABIArgInfo::CoerceAndExpand:
case ABIArgInfo::InAlloca:
llvm_unreachable("Unsupported ABI kind for va_arg");
case ABIArgInfo::Ignore:
Val = Address(llvm::UndefValue::get(ArgPtrTy), ArgTy, TypeAlign);
ArgSize = CharUnits::Zero();
break;
case ABIArgInfo::Extend:
case ABIArgInfo::Direct:
Val = AP.withElementType(ArgTy);
ArgSize = CharUnits::fromQuantity(
getDataLayout().getTypeAllocSize(AI.getCoerceToType()));
ArgSize = ArgSize.alignTo(SlotSize);
break;
case ABIArgInfo::Indirect:
case ABIArgInfo::IndirectAliased:
Val = AP.withElementType(ArgPtrTy);
Val = Address(Builder.CreateLoad(Val), ArgTy, TypeAlign);
ArgSize = SlotSize;
break;
}
// Increment the VAList.
if (!ArgSize.isZero()) {
Address APN = Builder.CreateConstInBoundsByteGEP(AP, ArgSize);
Builder.CreateStore(APN.getPointer(), VAListAddr);
}
return Val;
}
/// During the expansion of a RecordType, an incomplete TypeString is placed
/// into the cache as a means to identify and break recursion.
/// If there is a Recursive encoding in the cache, it is swapped out and will
/// be reinserted by removeIncomplete().
/// All other types of encoding should have been used rather than arriving here.
void TypeStringCache::addIncomplete(const IdentifierInfo *ID,
std::string StubEnc) {
if (!ID)
return;
Entry &E = Map[ID];
assert( (E.Str.empty() || E.State == Recursive) &&
"Incorrectly use of addIncomplete");
assert(!StubEnc.empty() && "Passing an empty string to addIncomplete()");
E.Swapped.swap(E.Str); // swap out the Recursive
E.Str.swap(StubEnc);
E.State = Incomplete;
++IncompleteCount;
}
/// Once the RecordType has been expanded, the temporary incomplete TypeString
/// must be removed from the cache.
/// If a Recursive was swapped out by addIncomplete(), it will be replaced.
/// Returns true if the RecordType was defined recursively.
bool TypeStringCache::removeIncomplete(const IdentifierInfo *ID) {
if (!ID)
return false;
auto I = Map.find(ID);
assert(I != Map.end() && "Entry not present");
Entry &E = I->second;
assert( (E.State == Incomplete ||
E.State == IncompleteUsed) &&
"Entry must be an incomplete type");
bool IsRecursive = false;
if (E.State == IncompleteUsed) {
// We made use of our Incomplete encoding, thus we are recursive.
IsRecursive = true;
--IncompleteUsedCount;
}
if (E.Swapped.empty())
Map.erase(I);
else {
// Swap the Recursive back.
E.Swapped.swap(E.Str);
E.Swapped.clear();
E.State = Recursive;
}
--IncompleteCount;
return IsRecursive;
}
/// Add the encoded TypeString to the cache only if it is NonRecursive or
/// Recursive (viz: all sub-members were expanded as fully as possible).
void TypeStringCache::addIfComplete(const IdentifierInfo *ID, StringRef Str,
bool IsRecursive) {
if (!ID || IncompleteUsedCount)
return; // No key or it is an incomplete sub-type so don't add.
Entry &E = Map[ID];
if (IsRecursive && !E.Str.empty()) {
assert(E.State==Recursive && E.Str.size() == Str.size() &&
"This is not the same Recursive entry");
// The parent container was not recursive after all, so we could have used
// this Recursive sub-member entry after all, but we assumed the worse when
// we started viz: IncompleteCount!=0.
return;
}
assert(E.Str.empty() && "Entry already present");
E.Str = Str.str();
E.State = IsRecursive? Recursive : NonRecursive;
}
/// Return a cached TypeString encoding for the ID. If there isn't one, or we
/// are recursively expanding a type (IncompleteCount != 0) and the cached
/// encoding is Recursive, return an empty StringRef.
StringRef TypeStringCache::lookupStr(const IdentifierInfo *ID) {
if (!ID)
return StringRef(); // We have no key.
auto I = Map.find(ID);
if (I == Map.end())
return StringRef(); // We have no encoding.
Entry &E = I->second;
if (E.State == Recursive && IncompleteCount)
return StringRef(); // We don't use Recursive encodings for member types.
if (E.State == Incomplete) {
// The incomplete type is being used to break out of recursion.
E.State = IncompleteUsed;
++IncompleteUsedCount;
}
return E.Str;
}
/// The XCore ABI includes a type information section that communicates symbol
/// type information to the linker. The linker uses this information to verify
/// safety/correctness of things such as array bound and pointers et al.
/// The ABI only requires C (and XC) language modules to emit TypeStrings.
/// This type information (TypeString) is emitted into meta data for all global
/// symbols: definitions, declarations, functions & variables.
///
/// The TypeString carries type, qualifier, name, size & value details.
/// Please see 'Tools Development Guide' section 2.16.2 for format details:
/// https://www.xmos.com/download/public/Tools-Development-Guide%28X9114A%29.pdf
/// The output is tested by test/CodeGen/xcore-stringtype.c.
///
static bool getTypeString(SmallStringEnc &Enc, const Decl *D,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC);
/// XCore uses emitTargetMD to emit TypeString metadata for global symbols.
void XCoreTargetCodeGenInfo::emitTargetMD(
const Decl *D, llvm::GlobalValue *GV,
const CodeGen::CodeGenModule &CGM) const {
SmallStringEnc Enc;
if (getTypeString(Enc, D, CGM, TSC)) {
llvm::LLVMContext &Ctx = CGM.getModule().getContext();
llvm::Metadata *MDVals[] = {llvm::ConstantAsMetadata::get(GV),
llvm::MDString::get(Ctx, Enc.str())};
llvm::NamedMDNode *MD =
CGM.getModule().getOrInsertNamedMetadata("xcore.typestrings");
MD->addOperand(llvm::MDNode::get(Ctx, MDVals));
}
}
void XCoreTargetCodeGenInfo::emitTargetMetadata(
CodeGen::CodeGenModule &CGM,
const llvm::MapVector<GlobalDecl, StringRef> &MangledDeclNames) const {
// Warning, new MangledDeclNames may be appended within this loop.
// We rely on MapVector insertions adding new elements to the end
// of the container.
for (unsigned I = 0; I != MangledDeclNames.size(); ++I) {
auto Val = *(MangledDeclNames.begin() + I);
llvm::GlobalValue *GV = CGM.GetGlobalValue(Val.second);
if (GV) {
const Decl *D = Val.first.getDecl()->getMostRecentDecl();
emitTargetMD(D, GV, CGM);
}
}
}
static bool appendType(SmallStringEnc &Enc, QualType QType,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC);
/// Helper function for appendRecordType().
/// Builds a SmallVector containing the encoded field types in declaration
/// order.
static bool extractFieldType(SmallVectorImpl<FieldEncoding> &FE,
const RecordDecl *RD,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC) {
for (const auto *Field : RD->fields()) {
SmallStringEnc Enc;
Enc += "m(";
Enc += Field->getName();
Enc += "){";
if (Field->isBitField()) {
Enc += "b(";
llvm::raw_svector_ostream OS(Enc);
OS << Field->getBitWidthValue(CGM.getContext());
Enc += ':';
}
if (!appendType(Enc, Field->getType(), CGM, TSC))
return false;
if (Field->isBitField())
Enc += ')';
Enc += '}';
FE.emplace_back(!Field->getName().empty(), Enc);
}
return true;
}
/// Appends structure and union types to Enc and adds encoding to cache.
/// Recursively calls appendType (via extractFieldType) for each field.
/// Union types have their fields ordered according to the ABI.
static bool appendRecordType(SmallStringEnc &Enc, const RecordType *RT,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC, const IdentifierInfo *ID) {
// Append the cached TypeString if we have one.
StringRef TypeString = TSC.lookupStr(ID);
if (!TypeString.empty()) {
Enc += TypeString;
return true;
}
// Start to emit an incomplete TypeString.
size_t Start = Enc.size();
Enc += (RT->isUnionType()? 'u' : 's');
Enc += '(';
if (ID)
Enc += ID->getName();
Enc += "){";
// We collect all encoded fields and order as necessary.
bool IsRecursive = false;
const RecordDecl *RD = RT->getDecl()->getDefinition();
if (RD && !RD->field_empty()) {
// An incomplete TypeString stub is placed in the cache for this RecordType
// so that recursive calls to this RecordType will use it whilst building a
// complete TypeString for this RecordType.
SmallVector<FieldEncoding, 16> FE;
std::string StubEnc(Enc.substr(Start).str());
StubEnc += '}'; // StubEnc now holds a valid incomplete TypeString.
TSC.addIncomplete(ID, std::move(StubEnc));
if (!extractFieldType(FE, RD, CGM, TSC)) {
(void) TSC.removeIncomplete(ID);
return false;
}
IsRecursive = TSC.removeIncomplete(ID);
// The ABI requires unions to be sorted but not structures.
// See FieldEncoding::operator< for sort algorithm.
if (RT->isUnionType())
llvm::sort(FE);
// We can now complete the TypeString.
unsigned E = FE.size();
for (unsigned I = 0; I != E; ++I) {
if (I)
Enc += ',';
Enc += FE[I].str();
}
}
Enc += '}';
TSC.addIfComplete(ID, Enc.substr(Start), IsRecursive);
return true;
}
/// Appends enum types to Enc and adds the encoding to the cache.
static bool appendEnumType(SmallStringEnc &Enc, const EnumType *ET,
TypeStringCache &TSC,
const IdentifierInfo *ID) {
// Append the cached TypeString if we have one.
StringRef TypeString = TSC.lookupStr(ID);
if (!TypeString.empty()) {
Enc += TypeString;
return true;
}
size_t Start = Enc.size();
Enc += "e(";
if (ID)
Enc += ID->getName();
Enc += "){";
// We collect all encoded enumerations and order them alphanumerically.
if (const EnumDecl *ED = ET->getDecl()->getDefinition()) {
SmallVector<FieldEncoding, 16> FE;
for (auto I = ED->enumerator_begin(), E = ED->enumerator_end(); I != E;
++I) {
SmallStringEnc EnumEnc;
EnumEnc += "m(";
EnumEnc += I->getName();
EnumEnc += "){";
I->getInitVal().toString(EnumEnc);
EnumEnc += '}';
FE.push_back(FieldEncoding(!I->getName().empty(), EnumEnc));
}
llvm::sort(FE);
unsigned E = FE.size();
for (unsigned I = 0; I != E; ++I) {
if (I)
Enc += ',';
Enc += FE[I].str();
}
}
Enc += '}';
TSC.addIfComplete(ID, Enc.substr(Start), false);
return true;
}
/// Appends type's qualifier to Enc.
/// This is done prior to appending the type's encoding.
static void appendQualifier(SmallStringEnc &Enc, QualType QT) {
// Qualifiers are emitted in alphabetical order.
static const char *const Table[]={"","c:","r:","cr:","v:","cv:","rv:","crv:"};
int Lookup = 0;
if (QT.isConstQualified())
Lookup += 1<<0;
if (QT.isRestrictQualified())
Lookup += 1<<1;
if (QT.isVolatileQualified())
Lookup += 1<<2;
Enc += Table[Lookup];
}
/// Appends built-in types to Enc.
static bool appendBuiltinType(SmallStringEnc &Enc, const BuiltinType *BT) {
const char *EncType;
switch (BT->getKind()) {
case BuiltinType::Void:
EncType = "0";
break;
case BuiltinType::Bool:
EncType = "b";
break;
case BuiltinType::Char_U:
EncType = "uc";
break;
case BuiltinType::UChar:
EncType = "uc";
break;
case BuiltinType::SChar:
EncType = "sc";
break;
case BuiltinType::UShort:
EncType = "us";
break;
case BuiltinType::Short:
EncType = "ss";
break;
case BuiltinType::UInt:
EncType = "ui";
break;
case BuiltinType::Int:
EncType = "si";
break;
case BuiltinType::ULong:
EncType = "ul";
break;
case BuiltinType::Long:
EncType = "sl";
break;
case BuiltinType::ULongLong:
EncType = "ull";
break;
case BuiltinType::LongLong:
EncType = "sll";
break;
case BuiltinType::Float:
EncType = "ft";
break;
case BuiltinType::Double:
EncType = "d";
break;
case BuiltinType::LongDouble:
EncType = "ld";
break;
default:
return false;
}
Enc += EncType;
return true;
}
/// Appends a pointer encoding to Enc before calling appendType for the pointee.
static bool appendPointerType(SmallStringEnc &Enc, const PointerType *PT,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC) {
Enc += "p(";
if (!appendType(Enc, PT->getPointeeType(), CGM, TSC))
return false;
Enc += ')';
return true;
}
/// Appends array encoding to Enc before calling appendType for the element.
static bool appendArrayType(SmallStringEnc &Enc, QualType QT,
const ArrayType *AT,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC, StringRef NoSizeEnc) {
if (AT->getSizeModifier() != ArraySizeModifier::Normal)
return false;
Enc += "a(";
if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
CAT->getSize().toStringUnsigned(Enc);
else
Enc += NoSizeEnc; // Global arrays use "*", otherwise it is "".
Enc += ':';
// The Qualifiers should be attached to the type rather than the array.
appendQualifier(Enc, QT);
if (!appendType(Enc, AT->getElementType(), CGM, TSC))
return false;
Enc += ')';
return true;
}
/// Appends a function encoding to Enc, calling appendType for the return type
/// and the arguments.
static bool appendFunctionType(SmallStringEnc &Enc, const FunctionType *FT,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC) {
Enc += "f{";
if (!appendType(Enc, FT->getReturnType(), CGM, TSC))
return false;
Enc += "}(";
if (const FunctionProtoType *FPT = FT->getAs<FunctionProtoType>()) {
// N.B. we are only interested in the adjusted param types.
auto I = FPT->param_type_begin();
auto E = FPT->param_type_end();
if (I != E) {
do {
if (!appendType(Enc, *I, CGM, TSC))
return false;
++I;
if (I != E)
Enc += ',';
} while (I != E);
if (FPT->isVariadic())
Enc += ",va";
} else {
if (FPT->isVariadic())
Enc += "va";
else
Enc += '0';
}
}
Enc += ')';
return true;
}
/// Handles the type's qualifier before dispatching a call to handle specific
/// type encodings.
static bool appendType(SmallStringEnc &Enc, QualType QType,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC) {
QualType QT = QType.getCanonicalType();
if (const ArrayType *AT = QT->getAsArrayTypeUnsafe())
// The Qualifiers should be attached to the type rather than the array.
// Thus we don't call appendQualifier() here.
return appendArrayType(Enc, QT, AT, CGM, TSC, "");
appendQualifier(Enc, QT);
if (const BuiltinType *BT = QT->getAs<BuiltinType>())
return appendBuiltinType(Enc, BT);
if (const PointerType *PT = QT->getAs<PointerType>())
return appendPointerType(Enc, PT, CGM, TSC);
if (const EnumType *ET = QT->getAs<EnumType>())
return appendEnumType(Enc, ET, TSC, QT.getBaseTypeIdentifier());
if (const RecordType *RT = QT->getAsStructureType())
return appendRecordType(Enc, RT, CGM, TSC, QT.getBaseTypeIdentifier());
if (const RecordType *RT = QT->getAsUnionType())
return appendRecordType(Enc, RT, CGM, TSC, QT.getBaseTypeIdentifier());
if (const FunctionType *FT = QT->getAs<FunctionType>())
return appendFunctionType(Enc, FT, CGM, TSC);
return false;
}
static bool getTypeString(SmallStringEnc &Enc, const Decl *D,
const CodeGen::CodeGenModule &CGM,
TypeStringCache &TSC) {
if (!D)
return false;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
if (FD->getLanguageLinkage() != CLanguageLinkage)
return false;
return appendType(Enc, FD->getType(), CGM, TSC);
}
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (VD->getLanguageLinkage() != CLanguageLinkage)
return false;
QualType QT = VD->getType().getCanonicalType();
if (const ArrayType *AT = QT->getAsArrayTypeUnsafe()) {
// Global ArrayTypes are given a size of '*' if the size is unknown.
// The Qualifiers should be attached to the type rather than the array.
// Thus we don't call appendQualifier() here.
return appendArrayType(Enc, QT, AT, CGM, TSC, "*");
}
return appendType(Enc, QT, CGM, TSC);
}
return false;
}
std::unique_ptr<TargetCodeGenInfo>
CodeGen::createXCoreTargetCodeGenInfo(CodeGenModule &CGM) {
return std::make_unique<XCoreTargetCodeGenInfo>(CGM.getTypes());
}