Disable debug timers in non-CPP2_DEBUG_BUILD builds

And improve timer performance by removing `make_shared`

Author: hsutter

Diff for: source/common.h

@@ -23,6 +23,14 @@
 #include "cpp2util.h"
 
 
+//===========================================================================
+//  When defined, builds cppfront in an instrumented (and slower) mode that
+//  prints more information under -_debug
+//===========================================================================
+
+//#define CPP2_DEBUG_BUILD
+
+
 //===========================================================================
 //  Common types
 //===========================================================================
@@ -1005,6 +1013,7 @@ class stable_vector
     }
 
     auto size() const -> size_t {
+        testing.enforce(!data.empty());
         return (data.size() - 1) * PageSize + data.back().size();
     }
 
@@ -1359,16 +1368,19 @@ class timer
 
 static std::unordered_map<std::string_view, timer> timers;  // global named timers
 
-auto scope_timer(std::string_view name) -> std::shared_ptr<void> {
-    if (flag_internal_debug) {
-        timers[name].start();
-        auto stop = [=]{ timers[name].stop(); };
-        return std::make_shared<finally<decltype(stop)>>( std::move(stop) );
-    }
-    //  Else
-    return {};
+auto scope_timer(std::string_view name) {
+    timers[name].start();
+    auto stop = [=]{ timers[name].stop(); };
+    return finally( std::move(stop) );
 }
 
+#ifdef CPP2_DEBUG_BUILD
+#define CPP2_CONCAT(x,y)       x##y
+#define CPP2_UNIQUE_NAME(x,y)  CPP2_CONCAT(x,y)
+#define CPP2_SCOPE_TIMER(name) auto CPP2_UNIQUE_NAME(timer,__LINE__) = scope_timer(name)
+#else
+#define CPP2_SCOPE_TIMER(name)
+#endif
 
 }
 

Diff for: source/sema.h

@@ -481,7 +481,7 @@ class sema
         }
         //--------- END TEMPORARY REGRESSION TEST CODE FOR G_D_O OPTIMIZATION VERIFICATION -----------
 
-        auto timer = scope_timer("get_declaration_of_new - including external caching");
+        CPP2_SCOPE_TIMER("get_declaration_of_new - including external caching");
 
         //  Check the cache first to avoid duplicate computations
         //
@@ -554,7 +554,7 @@ class sema
     ) const
         -> declaration_sym const*
     {
-        auto timer  = scope_timer("get_declaration_of - old");
+        CPP2_SCOPE_TIMER("get_declaration_of - old");
 
         //  First find the position the query is coming from
         //  and remember its depth
@@ -750,15 +750,15 @@ class sema
     ) const
         -> declaration_sym const*
     {
-        auto timer = scope_timer("get_declaration_of_new");
+        CPP2_SCOPE_TIMER("get_declaration_of_new");
 
         //  First find the position the query is coming from
         //  and remember its depth
         auto i = symbols.cbegin();
         auto depth = 0;
 
         {
-        auto timer1 = scope_timer("get_declaration_of_new - phase 1 initial loop");
+        CPP2_SCOPE_TIMER("get_declaration_of_new - phase 1 initial loop");
 
         //  If the declaration_starts list got this far yet, use that to
         //  skip repeating the whole linear search from the table beginning
@@ -887,20 +887,20 @@ class sema
         }
         }
 
-        auto timer2 = scope_timer("get_declaration_of_new - phase 2 backward scan loop");
+        CPP2_SCOPE_TIMER("get_declaration_of_new - phase 2 backward scan loop");
 
         //  Then look backward to find the first declaration of
         //  this name that is not deeper (in a nested scope)
         //  and is in the same function
         using I = stable_vector<symbol>::const_iterator;
         auto advance = [](I& i, int n, I bound) {  // TODO Use `std::ranges::advance`
-            auto timer2a = scope_timer("get_declaration_of_new - phase 2a 'advance' part of loop");
+            CPP2_SCOPE_TIMER("get_declaration_of_new - phase 2a 'advance' part of loop");
             auto in = i;
             if (std::abs(n) >= std::abs(bound - i)) {
                 i = bound;
             }
             else {
-                auto timer2aa = scope_timer("get_declaration_of_new - phase 2aa 'std::advance' specifically");
+                CPP2_SCOPE_TIMER("get_declaration_of_new - phase 2aa 'std::advance' specifically");
                 std::advance(i, n);
             }
             return n - (i - in);
@@ -942,7 +942,7 @@ class sema
                     return &decl;
                 }
 
-                auto timer2b = scope_timer("get_declaration_of_new - phase 2b 'move this' part of loop");
+                CPP2_SCOPE_TIMER("get_declaration_of_new - phase 2b 'move this' part of loop");
 
                 //  If we reached a 'move this' parameter, look it up in the type members
                 if (