streamline generated -O C++ code by relying on per-function profiles rather than aggregate profile

src/script_opt/CPP/Driver.cc

@@ -29,6 +29,7 @@ CPPCompile::CPPCompile(vector<FuncInfo>& _funcs, std::shared_ptr<ProfileFuncs> _
 CPPCompile::~CPPCompile() { fclose(write_file); }
 
 void CPPCompile::Compile(bool report_uncompilable) {
+    unordered_set<const Type*> rep_types;
     unordered_set<string> filenames_reported_as_skipped;
     bool had_to_skip = false;
 
@@ -63,6 +64,24 @@ void CPPCompile::Compile(bool report_uncompilable) {
             continue;
         }
 
+        auto pf = func.Profile();
+        total_hash = merge_p_hashes(total_hash, pf->HashVal());
+
+        for ( auto t : pf->UnorderedTypes() )
+            rep_types.insert(pfs->TypeRep(t));
+
+        auto& pf_all_gl = pf->AllGlobals();
+        all_accessed_globals.insert(pf_all_gl.begin(), pf_all_gl.end());
+
+        auto& pf_gl = pf->Globals();
+        accessed_globals.insert(pf_gl.begin(), pf_gl.end());
+
+        auto& pf_events = pf->Events();
+        accessed_events.insert(pf_events.begin(), pf_events.end());
+
+        auto& pf_lambdas = pf->Lambdas();
+        accessed_lambdas.insert(pf_lambdas.begin(), pf_lambdas.end());
+
         if ( is_lambda(f) || is_when_lambda(f) ) {
             // We deal with these separately.
             func.SetSkip(true);
@@ -85,35 +104,35 @@ void CPPCompile::Compile(bool report_uncompilable) {
         }
     }
 
-    if ( standalone && had_to_skip )
-        reporter->FatalError("aborting standalone compilation to C++ due to having to skip some functions");
-
     // Generate a hash unique for this compilation.
     for ( const auto& func : funcs )
         if ( ! func.ShouldSkip() )
             total_hash = merge_p_hashes(total_hash, func.Profile()->HashVal());
 
+    if ( standalone && had_to_skip )
+        reporter->FatalError("aborting standalone compilation to C++ due to having to skip some functions");
+
     auto t = util::current_time();
     total_hash = merge_p_hashes(total_hash, hash<double>{}(t));
 
     GenProlog();
 
     // Track all of the types we'll be using.
-    for ( const auto& t : pfs->RepTypes() ) {
+    for ( const auto& t : rep_types ) {
         TypePtr tp{NewRef{}, (Type*)(t)};
         types.AddKey(tp, pfs->HashType(t));
     }
 
     NL();
 
-    for ( auto& g : pfs->AllGlobals() )
+    for ( auto& g : all_accessed_globals )
         CreateGlobal(g);
 
-    for ( const auto& e : pfs->Events() )
+    for ( const auto& e : accessed_events )
         if ( AddGlobal(e, "gl") )
             Emit("EventHandlerPtr %s_ev;", globals[string(e)]);
 
-    for ( const auto& t : pfs->RepTypes() ) {
+    for ( const auto& t : rep_types ) {
         ASSERT(types.HasKey(t));
         TypePtr tp{NewRef{}, (Type*)(t)};
         RegisterType(tp);
@@ -131,7 +150,7 @@ void CPPCompile::Compile(bool report_uncompilable) {
     // be identical.  In that case, we don't want to generate the lambda
     // twice, but we do want to map the second one to the same body name.
     unordered_map<string, const Stmt*> lambda_ASTs;
-    for ( const auto& l : pfs->Lambdas() ) {
+    for ( const auto& l : accessed_lambdas ) {
         const auto& n = l->Name();
         const auto body = l->Ingredients()->Body().get();
         if ( lambda_ASTs.count(n) > 0 )
@@ -151,7 +170,7 @@ void CPPCompile::Compile(bool report_uncompilable) {
             CompileFunc(func);
 
     lambda_ASTs.clear();
-    for ( const auto& l : pfs->Lambdas() ) {
+    for ( const auto& l : accessed_lambdas ) {
         const auto& n = l->Name();
         if ( lambda_ASTs.count(n) > 0 )
             continue;

src/script_opt/CPP/Exprs.cc

@@ -308,9 +308,8 @@ string CPPCompile::GenCallExpr(const CallExpr* c, GenType gt, bool top_level) {
         if ( pfs->BiFGlobals().count(f_id) == 0 )
             gen += +"->AsFunc()";
 
-        else if ( pfs->Globals().count(f_id) > 0 )
-            // The BiF version has an extra "_", per
-            // AddBiF(..., true).
+        else if ( accessed_globals.count(f_id) > 0 )
+            // The BiF version has an extra "_", per AddBiF(..., true).
             gen = globals[string(id_name) + "_"];
     }
 

src/script_opt/CPP/Vars.h

@@ -53,6 +53,19 @@ std::string Canonicalize(const std::string& name) const;
 // be a EXPR_NAME).
 std::string GlobalName(const ExprPtr& e) { return globals[e->AsNameExpr()->Id()->Name()]; }
 
+// Globals that are used (appear in the profiles) of the bodies we're
+// compiling. Includes globals just used as functions to call.
+std::unordered_set<const ID*> all_accessed_globals;
+
+// Same, but just the globals used in contexts beyond function calls.
+std::unordered_set<const ID*> accessed_globals;
+
+// Lambdas that are accessed.
+std::unordered_set<const LambdaExpr*> accessed_lambdas;
+
+// Events that are accessed.
+std::unordered_set<std::string> accessed_events;
+
 // Maps global names (not identifiers) to the names we use for them.
 std::unordered_map<std::string, std::string> globals;