diff options
| -rw-r--r-- | src/libexpr/eval.cc | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 2d7309738..5bf161cc0 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -63,9 +63,15 @@ static char * dupString(const char * s) } -static char * dupStringWithLen(const char * s, size_t size) +// When there's no need to write to the string, we can optimize away empty +// string allocations. +// This function handles makeImmutableStringWithLen(null, 0) by returning the +// empty string. +static const char * makeImmutableStringWithLen(const char * s, size_t size) { char * t; + if (size == 0) + return ""; #if HAVE_BOEHMGC t = GC_STRNDUP(s, size); #else @@ -75,6 +81,10 @@ static char * dupStringWithLen(const char * s, size_t size) return t; } +static inline const char * makeImmutableString(std::string_view s) { + return makeImmutableStringWithLen(s.data(), s.size()); +} + RootValue allocRootValue(Value * v) { @@ -805,7 +815,7 @@ LocalNoInline(void addErrorTrace(Error & e, const Pos & pos, const char * s, con void Value::mkString(std::string_view s) { - mkString(dupStringWithLen(s.data(), s.size())); + mkString(makeImmutableString(s)); } @@ -836,7 +846,7 @@ void Value::mkStringMove(const char * s, const PathSet & context) void Value::mkPath(std::string_view s) { - mkPath(dupStringWithLen(s.data(), s.size())); + mkPath(makeImmutableString(s)); } |