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Dec 14, 2024
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Revert "Switch builtin strings to use string tables" #119638

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333befd
Revert "Switch builtin strings to use string tables (#118734)"
chandlerc Dec 11, 2024
ff92274
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chandlerc Dec 12, 2024
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203 changes: 34 additions & 169 deletions clang/include/clang/Basic/Builtins.h
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Expand Up @@ -55,7 +55,6 @@ struct HeaderDesc {
#undef HEADER
} ID;

constexpr HeaderDesc() : ID() {}
constexpr HeaderDesc(HeaderID ID) : ID(ID) {}

const char *getName() const;
Expand All @@ -69,152 +68,23 @@ enum ID {
FirstTSBuiltin
};

// The info used to represent each builtin.
struct Info {
// Rather than store pointers to the string literals describing these four
// aspects of builtins, we store offsets into a common string table.
struct StrOffsets {
int Name;
int Type;
int Attributes;
int Features;
} Offsets;

llvm::StringLiteral Name;
const char *Type, *Attributes;
const char *Features;
HeaderDesc Header;
LanguageID Langs;
};

// The storage for `N` builtins. This contains a single pointer to the string
// table used for these builtins and an array of metadata for each builtin.
template <size_t N> struct Storage {
const char *StringTable;

std::array<Info, N> Infos;

// A constexpr function to construct the storage for a a given string table in
// the first argument and an array in the second argument. This is *only*
// expected to be used at compile time, we should mark it `consteval` when
// available.
//
// The `Infos` array is particularly special. This function expects an array
// of `Info` structs, where the string offsets of each entry refer to the
// *sizes* of those strings rather than their offsets, and for the target
// string to be in the provided string table at an offset the sum of all
// previous string sizes. This function walks the `Infos` array computing the
// running sum and replacing the sizes with the actual offsets in the string
// table that should be used. This arrangement is designed to make it easy to
// expand `.def` and `.inc` files with X-macros to construct both the string
// table and the `Info` structs in the arguments to this function.
static constexpr Storage<N> Make(const char *Strings,
std::array<Info, N> Infos) {
// Translate lengths to offsets.
int Offset = 0;
for (auto &I : Infos) {
Info::StrOffsets NewOffsets = {};
NewOffsets.Name = Offset;
Offset += I.Offsets.Name;
NewOffsets.Type = Offset;
Offset += I.Offsets.Type;
NewOffsets.Attributes = Offset;
Offset += I.Offsets.Attributes;
NewOffsets.Features = Offset;
Offset += I.Offsets.Features;
I.Offsets = NewOffsets;
}
return {Strings, Infos};
}
};

// A detail macro used below to emit a string literal that, after string literal
// concatenation, ends up triggering the `-Woverlength-strings` warning. While
// the warning is useful in general to catch accidentally excessive strings,
// here we are creating them intentionally.
//
// This relies on a subtle aspect of `_Pragma`: that the *diagnostic* ones don't
// turn into actual tokens that would disrupt string literal concatenation.
#ifdef __clang__
#define CLANG_BUILTIN_DETAIL_STR_TABLE(S) \
_Pragma("clang diagnostic push") \
_Pragma("clang diagnostic ignored \"-Woverlength-strings\"") \
S _Pragma("clang diagnostic pop")
#else
#define CLANG_BUILTIN_DETAIL_STR_TABLE(S) S
#endif

// A macro that can be used with `Builtins.def` and similar files as an X-macro
// to add the string arguments to a builtin string table. This is typically the
// target for the `BUILTIN`, `LANGBUILTIN`, or `LIBBUILTIN` macros in those
// files.
#define CLANG_BUILTIN_STR_TABLE(ID, TYPE, ATTRS) \
CLANG_BUILTIN_DETAIL_STR_TABLE(#ID "\0" TYPE "\0" ATTRS "\0" /*FEATURE*/ "\0")

// A macro that can be used with target builtin `.def` and `.inc` files as an
// X-macro to add the string arguments to a builtin string table. this is
// typically the target for the `TARGET_BUILTIN` macro.
#define CLANG_TARGET_BUILTIN_STR_TABLE(ID, TYPE, ATTRS, FEATURE) \
CLANG_BUILTIN_DETAIL_STR_TABLE(#ID "\0" TYPE "\0" ATTRS "\0" FEATURE "\0")

// A macro that can be used with target builtin `.def` and `.inc` files as an
// X-macro to add the string arguments to a builtin string table. this is
// typically the target for the `TARGET_HEADER_BUILTIN` macro. We can't delegate
// to `TARGET_BUILTIN` because the `FEATURE` string changes position.
#define CLANG_TARGET_HEADER_BUILTIN_STR_TABLE(ID, TYPE, ATTRS, HEADER, LANGS, \
FEATURE) \
CLANG_BUILTIN_DETAIL_STR_TABLE(#ID "\0" TYPE "\0" ATTRS "\0" FEATURE "\0")

// A detail macro used internally to compute the desired string table
// `StrOffsets` struct for arguments to `Storage::Make`.
#define CLANG_BUILTIN_DETAIL_STR_OFFSETS(ID, TYPE, ATTRS) \
Builtin::Info::StrOffsets { \
sizeof(#ID), sizeof(TYPE), sizeof(ATTRS), sizeof("") \
}

// A detail macro used internally to compute the desired string table
// `StrOffsets` struct for arguments to `Storage::Make`.
#define CLANG_TARGET_BUILTIN_DETAIL_STR_OFFSETS(ID, TYPE, ATTRS, FEATURE) \
Builtin::Info::StrOffsets { \
sizeof(#ID), sizeof(TYPE), sizeof(ATTRS), sizeof(FEATURE) \
}

// A set of macros that can be used with builtin `.def' files as an X-macro to
// create an `Info` struct for a particular builtin. It both computes the
// `StrOffsets` value for the string table (the lengths here, translated to
// offsets by the Storage::Make function), and the other metadata for each
// builtin.
//
// There is a corresponding macro for each of `BUILTIN`, `LANGBUILTIN`,
// `LIBBUILTIN`, `TARGET_BUILTIN`, and `TARGET_HEADER_BUILTIN`.
#define CLANG_BUILTIN_ENTRY(ID, TYPE, ATTRS) \
Builtin::Info{CLANG_BUILTIN_DETAIL_STR_OFFSETS(ID, TYPE, ATTRS), \
HeaderDesc::NO_HEADER, ALL_LANGUAGES},
#define CLANG_LANGBUILTIN_ENTRY(ID, TYPE, ATTRS, LANG) \
Builtin::Info{CLANG_BUILTIN_DETAIL_STR_OFFSETS(ID, TYPE, ATTRS), \
HeaderDesc::NO_HEADER, LANG},
#define CLANG_LIBBUILTIN_ENTRY(ID, TYPE, ATTRS, HEADER, LANG) \
Builtin::Info{CLANG_BUILTIN_DETAIL_STR_OFFSETS(ID, TYPE, ATTRS), \
HeaderDesc::HEADER, LANG},
#define CLANG_TARGET_BUILTIN_ENTRY(ID, TYPE, ATTRS, FEATURE) \
Builtin::Info{ \
CLANG_TARGET_BUILTIN_DETAIL_STR_OFFSETS(ID, TYPE, ATTRS, FEATURE), \
HeaderDesc::NO_HEADER, ALL_LANGUAGES},
#define CLANG_TARGET_HEADER_BUILTIN_ENTRY(ID, TYPE, ATTRS, HEADER, LANG, \
FEATURE) \
Builtin::Info{ \
CLANG_TARGET_BUILTIN_DETAIL_STR_OFFSETS(ID, TYPE, ATTRS, FEATURE), \
HeaderDesc::HEADER, LANG},

/// Holds information about both target-independent and
/// target-specific builtins, allowing easy queries by clients.
///
/// Builtins from an optional auxiliary target are stored in
/// AuxTSRecords. Their IDs are shifted up by TSRecords.size() and need to
/// be translated back with getAuxBuiltinID() before use.
class Context {
const char *TSStrTable = nullptr;
const char *AuxTSStrTable = nullptr;

llvm::ArrayRef<Info> TSInfos;
llvm::ArrayRef<Info> AuxTSInfos;
llvm::ArrayRef<Info> TSRecords;
llvm::ArrayRef<Info> AuxTSRecords;

public:
Context() = default;
Expand All @@ -230,13 +100,10 @@ class Context {

/// Return the identifier name for the specified builtin,
/// e.g. "__builtin_abs".
llvm::StringRef getName(unsigned ID) const;
llvm::StringRef getName(unsigned ID) const { return getRecord(ID).Name; }

/// Get the type descriptor string for the specified builtin.
const char *getTypeString(unsigned ID) const;

/// Get the attributes descriptor string for the specified builtin.
const char *getAttributesString(unsigned ID) const;
const char *getTypeString(unsigned ID) const { return getRecord(ID).Type; }

/// Return true if this function is a target-specific builtin.
bool isTSBuiltin(unsigned ID) const {
Expand All @@ -245,40 +112,40 @@ class Context {

/// Return true if this function has no side effects.
bool isPure(unsigned ID) const {
return strchr(getAttributesString(ID), 'U') != nullptr;
return strchr(getRecord(ID).Attributes, 'U') != nullptr;
}

/// Return true if this function has no side effects and doesn't
/// read memory.
bool isConst(unsigned ID) const {
return strchr(getAttributesString(ID), 'c') != nullptr;
return strchr(getRecord(ID).Attributes, 'c') != nullptr;
}

/// Return true if we know this builtin never throws an exception.
bool isNoThrow(unsigned ID) const {
return strchr(getAttributesString(ID), 'n') != nullptr;
return strchr(getRecord(ID).Attributes, 'n') != nullptr;
}

/// Return true if we know this builtin never returns.
bool isNoReturn(unsigned ID) const {
return strchr(getAttributesString(ID), 'r') != nullptr;
return strchr(getRecord(ID).Attributes, 'r') != nullptr;
}

/// Return true if we know this builtin can return twice.
bool isReturnsTwice(unsigned ID) const {
return strchr(getAttributesString(ID), 'j') != nullptr;
return strchr(getRecord(ID).Attributes, 'j') != nullptr;
}

/// Returns true if this builtin does not perform the side-effects
/// of its arguments.
bool isUnevaluated(unsigned ID) const {
return strchr(getAttributesString(ID), 'u') != nullptr;
return strchr(getRecord(ID).Attributes, 'u') != nullptr;
}

/// Return true if this is a builtin for a libc/libm function,
/// with a "__builtin_" prefix (e.g. __builtin_abs).
bool isLibFunction(unsigned ID) const {
return strchr(getAttributesString(ID), 'F') != nullptr;
return strchr(getRecord(ID).Attributes, 'F') != nullptr;
}

/// Determines whether this builtin is a predefined libc/libm
Expand All @@ -289,29 +156,29 @@ class Context {
/// they do not, but they are recognized as builtins once we see
/// a declaration.
bool isPredefinedLibFunction(unsigned ID) const {
return strchr(getAttributesString(ID), 'f') != nullptr;
return strchr(getRecord(ID).Attributes, 'f') != nullptr;
}

/// Returns true if this builtin requires appropriate header in other
/// compilers. In Clang it will work even without including it, but we can emit
/// a warning about missing header.
bool isHeaderDependentFunction(unsigned ID) const {
return strchr(getAttributesString(ID), 'h') != nullptr;
return strchr(getRecord(ID).Attributes, 'h') != nullptr;
}

/// Determines whether this builtin is a predefined compiler-rt/libgcc
/// function, such as "__clear_cache", where we know the signature a
/// priori.
bool isPredefinedRuntimeFunction(unsigned ID) const {
return strchr(getAttributesString(ID), 'i') != nullptr;
return strchr(getRecord(ID).Attributes, 'i') != nullptr;
}

/// Determines whether this builtin is a C++ standard library function
/// that lives in (possibly-versioned) namespace std, possibly a template
/// specialization, where the signature is determined by the standard library
/// declaration.
bool isInStdNamespace(unsigned ID) const {
return strchr(getAttributesString(ID), 'z') != nullptr;
return strchr(getRecord(ID).Attributes, 'z') != nullptr;
}

/// Determines whether this builtin can have its address taken with no
Expand All @@ -325,33 +192,33 @@ class Context {

/// Determines whether this builtin has custom typechecking.
bool hasCustomTypechecking(unsigned ID) const {
return strchr(getAttributesString(ID), 't') != nullptr;
return strchr(getRecord(ID).Attributes, 't') != nullptr;
}

/// Determines whether a declaration of this builtin should be recognized
/// even if the type doesn't match the specified signature.
bool allowTypeMismatch(unsigned ID) const {
return strchr(getAttributesString(ID), 'T') != nullptr ||
return strchr(getRecord(ID).Attributes, 'T') != nullptr ||
hasCustomTypechecking(ID);
}

/// Determines whether this builtin has a result or any arguments which
/// are pointer types.
bool hasPtrArgsOrResult(unsigned ID) const {
return strchr(getTypeString(ID), '*') != nullptr;
return strchr(getRecord(ID).Type, '*') != nullptr;
}

/// Return true if this builtin has a result or any arguments which are
/// reference types.
bool hasReferenceArgsOrResult(unsigned ID) const {
return strchr(getTypeString(ID), '&') != nullptr ||
strchr(getTypeString(ID), 'A') != nullptr;
return strchr(getRecord(ID).Type, '&') != nullptr ||
strchr(getRecord(ID).Type, 'A') != nullptr;
}

/// If this is a library function that comes from a specific
/// header, retrieve that header name.
const char *getHeaderName(unsigned ID) const {
return getInfo(ID).Header.getName();
return getRecord(ID).Header.getName();
}

/// Determine whether this builtin is like printf in its
Expand All @@ -376,25 +243,27 @@ class Context {
/// Such functions can be const when the MathErrno lang option and FP
/// exceptions are disabled.
bool isConstWithoutErrnoAndExceptions(unsigned ID) const {
return strchr(getAttributesString(ID), 'e') != nullptr;
return strchr(getRecord(ID).Attributes, 'e') != nullptr;
}

bool isConstWithoutExceptions(unsigned ID) const {
return strchr(getAttributesString(ID), 'g') != nullptr;
return strchr(getRecord(ID).Attributes, 'g') != nullptr;
}

const char *getRequiredFeatures(unsigned ID) const;
const char *getRequiredFeatures(unsigned ID) const {
return getRecord(ID).Features;
}

unsigned getRequiredVectorWidth(unsigned ID) const;

/// Return true if builtin ID belongs to AuxTarget.
bool isAuxBuiltinID(unsigned ID) const {
return ID >= (Builtin::FirstTSBuiltin + TSInfos.size());
return ID >= (Builtin::FirstTSBuiltin + TSRecords.size());
}

/// Return real builtin ID (i.e. ID it would have during compilation
/// for AuxTarget).
unsigned getAuxBuiltinID(unsigned ID) const { return ID - TSInfos.size(); }
unsigned getAuxBuiltinID(unsigned ID) const { return ID - TSRecords.size(); }

/// Returns true if this is a libc/libm function without the '__builtin_'
/// prefix.
Expand All @@ -406,20 +275,16 @@ class Context {

/// Return true if this function can be constant evaluated by Clang frontend.
bool isConstantEvaluated(unsigned ID) const {
return strchr(getAttributesString(ID), 'E') != nullptr;
return strchr(getRecord(ID).Attributes, 'E') != nullptr;
}

/// Returns true if this is an immediate (consteval) function
bool isImmediate(unsigned ID) const {
return strchr(getAttributesString(ID), 'G') != nullptr;
return strchr(getRecord(ID).Attributes, 'G') != nullptr;
}

private:
std::pair<const char *, const Info &> getStrTableAndInfo(unsigned ID) const;

const Info &getInfo(unsigned ID) const {
return getStrTableAndInfo(ID).second;
}
const Info &getRecord(unsigned ID) const;

/// Helper function for isPrintfLike and isScanfLike.
bool isLike(unsigned ID, unsigned &FormatIdx, bool &HasVAListArg,
Expand Down
1 change: 0 additions & 1 deletion clang/include/clang/Basic/BuiltinsPPC.def
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Expand Up @@ -1138,6 +1138,5 @@ UNALIASED_CUSTOM_BUILTIN(mma_pmxvbf16ger2nn, "vW512*VVi15i15i3", true,
// FIXME: Obviously incomplete.

#undef BUILTIN
#undef TARGET_BUILTIN
#undef CUSTOM_BUILTIN
#undef UNALIASED_CUSTOM_BUILTIN
10 changes: 4 additions & 6 deletions clang/include/clang/Basic/TargetInfo.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,6 @@

#include "clang/Basic/AddressSpaces.h"
#include "clang/Basic/BitmaskEnum.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/CFProtectionOptions.h"
#include "clang/Basic/CodeGenOptions.h"
#include "clang/Basic/LLVM.h"
Expand Down Expand Up @@ -1010,11 +1009,10 @@ class TargetInfo : public TransferrableTargetInfo,
virtual void getTargetDefines(const LangOptions &Opts,
MacroBuilder &Builder) const = 0;

/// Return information about target-specific builtins for the current primary
/// target, and info about which builtins are non-portable across the current
/// set of primary and secondary targets.
virtual std::pair<const char *, ArrayRef<Builtin::Info>>
getTargetBuiltinStorage() const = 0;
/// Return information about target-specific builtins for
/// the current primary target, and info about which builtins are non-portable
/// across the current set of primary and secondary targets.
virtual ArrayRef<Builtin::Info> getTargetBuiltins() const = 0;

/// Returns target-specific min and max values VScale_Range.
virtual std::optional<std::pair<unsigned, unsigned>>
Expand Down
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