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[Support] Fix for non-constexpr __PRETTY_FUNCTION__ on older gcc #128212

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Merged
merged 1 commit into from
Feb 21, 2025
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[Support] Fix for non-constexpr __PRETTY_FUNCTION__ on older gcc #128212

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58 changes: 44 additions & 14 deletions llvm/include/llvm/Support/TypeName.h
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,17 @@

#include "llvm/ADT/StringRef.h"

// Versions of GCC prior to GCC 9 don't declare __PRETTY_FUNCTION__ as constexpr
#if defined(__clang__) || defined(_MSC_VER) || \
(defined(__GNUC__) && __GNUC__ >= 9)
#define LLVM_GET_TYPE_NAME_CONSTEXPR constexpr
#define LLVM_GET_TYPE_NAME_STATIC_ASSERT 1
#else
#define LLVM_GET_TYPE_NAME_CONSTEXPR
#define LLVM_GET_TYPE_NAME_STATIC_ASSERT 0
#include <cassert>
#endif

namespace llvm {

/// We provide a function which tries to compute the (demangled) name of a type
Expand All @@ -25,50 +36,65 @@ namespace llvm {
/// The returned StringRef will point into a static storage duration string.
/// However, it may not be null terminated and may be some strangely aligned
/// inner substring of a larger string.
template <typename DesiredTypeName> inline constexpr StringRef getTypeName() {
template <typename DesiredTypeName>
inline LLVM_GET_TYPE_NAME_CONSTEXPR StringRef getTypeName() {
#if defined(__clang__) || defined(__GNUC__)
constexpr std::string_view Name = __PRETTY_FUNCTION__;
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view Name = __PRETTY_FUNCTION__;

constexpr std::string_view Key = "DesiredTypeName = ";
constexpr std::string_view TemplateParamsStart = Name.substr(Name.find(Key));
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view Key = "DesiredTypeName = ";
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view TemplateParamsStart =
Name.substr(Name.find(Key));
#if LLVM_GET_TYPE_NAME_STATIC_ASSERT
static_assert(!TemplateParamsStart.empty(),
"Unable to find the template parameter!");
constexpr std::string_view SubstitutionKey =
#else
assert(!TemplateParamsStart.empty() &&
"Unable to find the template parameter!");
#endif

LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view SubstitutionKey =
TemplateParamsStart.substr(Key.size());

#if LLVM_GET_TYPE_NAME_STATIC_ASSERT
// ends_with() is only available in c++20
static_assert(!SubstitutionKey.empty() && SubstitutionKey.back() == ']',
"Name doesn't end in the substitution key!");
#else
assert(!SubstitutionKey.empty() && SubstitutionKey.back() == ']' &&
"Name doesn't end in the substitution key!");
#endif

return SubstitutionKey.substr(0, SubstitutionKey.size() - 1);
#elif defined(_MSC_VER)
constexpr std::string_view Name = __FUNCSIG__;
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view Name = __FUNCSIG__;

constexpr std::string_view Key = "getTypeName<";
constexpr std::string_view GetTypeNameStart = Name.substr(Name.find(Key));
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view Key = "getTypeName<";
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view GetTypeNameStart =
Name.substr(Name.find(Key));
static_assert(!GetTypeNameStart.empty(),
"Unable to find the template parameter!");
constexpr std::string_view SubstitutionKey =
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view SubstitutionKey =
GetTypeNameStart.substr(Key.size());

// starts_with() only available in c++20
constexpr std::string_view RmPrefixClass =
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view RmPrefixClass =
SubstitutionKey.find("class ") == 0
? SubstitutionKey.substr(sizeof("class ") - 1)
: SubstitutionKey;
constexpr std::string_view RmPrefixStruct =
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view RmPrefixStruct =
RmPrefixClass.find("struct ") == 0
? RmPrefixClass.substr(sizeof("struct ") - 1)
: RmPrefixClass;
constexpr std::string_view RmPrefixUnion =
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view RmPrefixUnion =
RmPrefixStruct.find("union ") == 0
? RmPrefixStruct.substr(sizeof("union ") - 1)
: RmPrefixStruct;
constexpr std::string_view RmPrefixEnum =
LLVM_GET_TYPE_NAME_CONSTEXPR std::string_view RmPrefixEnum =
RmPrefixUnion.find("enum ") == 0
? RmPrefixUnion.substr(sizeof("enum ") - 1)
: RmPrefixUnion;

constexpr auto AnglePos = RmPrefixEnum.rfind('>');
LLVM_GET_TYPE_NAME_CONSTEXPR auto AnglePos = RmPrefixEnum.rfind('>');
static_assert(AnglePos != std::string_view::npos,
"Unable to find the closing '>'!");
return RmPrefixEnum.substr(0, AnglePos);
Expand All @@ -81,4 +107,8 @@ template <typename DesiredTypeName> inline constexpr StringRef getTypeName() {

} // namespace llvm

// Don't leak out of this header file
#undef LLVM_GET_TYPE_NAME_CONSTEXPR
#undef LLVM_GET_TYPE_NAME_STATIC_ASSERT

#endif