================
@@ -68,23 +69,156 @@ enum ID {
FirstTSBuiltin
};
+// The info used to represent each builtin.
struct Info {
- llvm::StringLiteral Name;
- const char *Type, *Attributes;
- const char *Features;
+ // 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;
+
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 {
\
+ llvm::StringLiteral(#ID).size() + 1, llvm::StringLiteral(TYPE).size() + 1,
\
+ llvm::StringLiteral(ATTRS).size() + 1,
\
+ llvm::StringLiteral("").size() + 1
\
----------------
nikic wrote:
```suggestion
sizeof(#ID), sizeof(TYPE), sizeof(ATTRS), sizeof("") \
```
https://github.com/llvm/llvm-project/pull/118734
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