Internals: Cleanup temp string inserts for clang-tidy. No functional change.

src/V3EmitC.cpp

@@ -1866,6 +1866,7 @@ void EmitCImp::emitSavableImp(AstNodeModule* modp) {
 	    string funcname = de ? "__Vdeserialize" : "__Vserialize";
 	    string writeread = de ? "read" : "write";
 	    string op = de ? ">>" : "<<";
+            // NOLINTNEXTLINE(performance-inefficient-string-concatenation)
 	    puts("void "+modClassName(modp)+"::"+funcname+"("+classname+"& os) {\n");
 	    // Place a computed checksum to insure proper structure save/restore formatting
 	    // OK if this hash includes some things we won't dump, since just looking for loading the wrong model

src/V3EmitCSyms.cpp

@@ -526,6 +526,7 @@ void EmitCSyms::emitSymImp() {
 	    string classname = de ? "VerilatedDeserialize" : "VerilatedSerialize";
 	    string funcname = de ? "__Vdeserialize" : "__Vserialize";
 	    string op = de ? ">>" : "<<";
+            // NOLINTNEXTLINE(performance-inefficient-string-concatenation)
 	    puts("void "+symClassName()+"::"+funcname+"("+classname+"& os) {\n");
 	    puts(   "// LOCAL STATE\n");
 	    // __Vm_namep presumably already correct

src/V3EmitMk.cpp

@@ -208,6 +208,7 @@ public:
 	    for (V3StringSet::const_iterator it = cppFiles.begin(); it != cppFiles.end(); ++it) {
 		string cppfile = *it;
 		string basename = V3Os::filenameNonExt(cppfile);
+                // NOLINTNEXTLINE(performance-inefficient-string-concatenation)
 		of.puts(basename+".o: "+cppfile+"\n");
 		of.puts("\t$(OBJCACHE) $(CXX) $(CXXFLAGS) $(CPPFLAGS) $(OPT_FAST) -c -o $@ $<\n");
 	    }

src/V3LangCode.h

@@ -23,6 +23,7 @@
 
 #include "config_build.h"
 #include "verilatedos.h"
+
 #include <string>
 #include <vector>
 #include <map>

src/V3Number.cpp

@@ -556,8 +556,8 @@ string V3Number::displayed(FileLine*fl, const string& vformat) const {
 	int intfmtsize = atoi(fmtsize.c_str());
 	bool zeropad = fmtsize.length()>0 && fmtsize[0]=='0';
 	while ((int)(str.length()) < intfmtsize) {
-	    if (zeropad) str = "0"+str;
-	    else str = " "+str;
+            if (zeropad) str.insert(0, "0");
+            else str.insert(0, " ");
 	}
 	return str;
     }

src/V3PreProc.cpp

@@ -818,7 +818,7 @@ int V3PreProcImp::getRawToken() {
 	    static string rtncmt;  // Keep the c string till next call
 	    rtncmt = m_lineCmt;
 	    if (m_lineCmtNl) {
-		if (!m_rawAtBol) rtncmt = "\n"+rtncmt;
+                if (!m_rawAtBol) rtncmt.insert(0, "\n");
 		m_lineCmtNl = false;
 	    }
 	    yyourtext(rtncmt.c_str(), rtncmt.length());
@@ -1099,7 +1099,7 @@ int V3PreProcImp::getStateToken() {
 		    if (state() == ps_JOIN) {  // Handle {left}```FOO(ARG) where `FOO(ARG) might be empty
 			if (m_joinStack.empty()) fatalSrc("`` join stack empty, but in a ``");
 			string lhs = m_joinStack.top(); m_joinStack.pop();
-			out = lhs+out;
+                        out.insert(0, lhs);
 			UINFO(5,"``-end-defarg Out:"<<out<<endl);
 			statePop();
 		    }
@@ -1323,7 +1323,7 @@ int V3PreProcImp::getStateToken() {
 			if (state() == ps_JOIN) {  // Handle {left}```FOO where `FOO might be empty
 			    if (m_joinStack.empty()) fatalSrc("`` join stack empty, but in a ``");
 			    string lhs = m_joinStack.top(); m_joinStack.pop();
-			    out = lhs+out;
+                            out.insert(0, lhs);
 			    UINFO(5,"``-end-defref Out:"<<out<<endl);
 			    statePop();
 			}

src/V3Task.cpp

@@ -859,8 +859,9 @@ private:
                         // At runtime we need the svOpenArrayHandle to point to this task & thread's data,
                         // in addition to static info about the variable
                         string name = portp->name()+"__Vopenarray";
-                        string varCode = ("VerilatedDpiOpenVar "+name
-                                          +" (&"+propName+", &"+portp->name()+");\n");
+                        string varCode = ("VerilatedDpiOpenVar "
+                                          // NOLINTNEXTLINE(performance-inefficient-string-concatenation)
+                                          +name+" (&"+propName+", &"+portp->name()+");\n");
                         cfuncp->addStmtsp(new AstCStmt(portp->fileline(), varCode));
                         args += "&"+name;
                     }