BUG: line and columns in file location are segfaulting tracy

I don't really get that one. As soon as we send those to tracy, we
segfault the profiler. I really don't get what's happening here.

We need to investigate this more to figure out what's happening.

configure.ac

@@ -351,11 +351,9 @@ fi
 AC_ARG_ENABLE(tracy-profiler, AS_HELP_STRING([--enable-tracy-profiler],[Profile the Nix evaluation using the Tracy profiler (default no)]),
   TRACY_PROFILER=$enableval, TRACY_PROFILER=no)
 if test "$TRACY_PROFILER" != no; then
+  # We don't have any pkg-config file for tracy, we have to inject the
+  # headers manually…
   CXXFLAGS="-I $TRACY_PROFILER/include/Tracy $CXXFLAGS"
-  echo "TRACY ENABLED: $TRACY_PROFILER"
-else
-  echo "TRACY DISABLED"
-  exit 1
 fi
 AC_SUBST(TRACY_PROFILER)
 

src/libexpr/eval.cc

@@ -57,12 +57,12 @@
 
 #define TRACY_TRACE(evalstate, expr) \
     std::ostringstream tracyss; \
-    tracyss << evalstate.positions[(expr)->getPos()] << " " << (expr)->showExprType(); \
+    tracyss << (evalstate).positions[(expr)->getPos()] << " " << (expr)->showExprType();      \
     ZoneTransientN(nix, tracyss.str().c_str(), true);
 
 #define TRACY_TRACE_TYPE_STR(evalstate, expr, typestr)   \
     std::ostringstream tracyss; \
-    tracyss << (evalstate).positions[(expr)->getPos()] << " " << typestr; \
+    tracyss << (evalstate).positions[(expr)->getPos()] << " " << typestr;      \
     ZoneTransientN(nix, tracyss.str().c_str(), true);
 
 using json = nlohmann::json;
@@ -81,7 +81,6 @@ static char * allocString(size_t size)
     return t;
 }
 
-
 static char * dupString(const char * s)
 {
     char * t;

src/libexpr/local.mk

@@ -22,6 +22,8 @@ ifdef HOST_LINUX
 endif
 ifneq ($(TRACY_PROFILER), no)
 libexpr_LDFLAGS += -ltracy
+# We have to set TRACY_ENABLE to have tracy actually send the trace
+# events, it's no-op without them.
 libexpr_CXXFLAGS += -DTRACY_ENABLE=1
 endif
 

src/libutil/position.cc

@@ -98,9 +98,6 @@ void Pos::print(std::ostream & out, bool showOrigin) const
         }, origin);
         out << ":";
     }
-    out << line;
-    if (column > 0)
-        out << ":" << column;
 }
 
 std::ostream & operator<<(std::ostream & str, const Pos & pos)