PP: Non-functional: Only use string <-> atom mapping when needed.

glslang/Include/revision.h

@@ -2,5 +2,5 @@
 // For the version, it uses the latest git tag followed by the number of commits.
 // For the date, it uses the current date (when then script is run).
 
-#define GLSLANG_REVISION "Overload400-PrecQual.1713"
+#define GLSLANG_REVISION "Overload400-PrecQual.1715"
 #define GLSLANG_DATE "20-Dec-2016"

glslang/MachineIndependent/preprocessor/PpAtom.cpp

@@ -120,7 +120,6 @@ const struct {
     { PpAtomIncrement,      "++" },
 
     { PpAtomDefine,         "define" },
-    { PpAtomDefined,        "defined" },
     { PpAtomUndef,          "undef" },
     { PpAtomIf,             "if" },
     { PpAtomElif,           "elif" },
@@ -150,16 +149,28 @@ const struct {
 namespace glslang {
 
 //
+// Map an existing string to an atom.
+//
+// Return 0 if no existing string.
+//
+int TPpContext::LookUpString(const char* s)
+{
+    auto it = atomMap.find(s);
+    return it == atomMap.end() ? 0 : it->second;
+}
+
+//
 // Map a new or existing string to an atom, inventing a new atom if necessary.
 //
 int TPpContext::LookUpAddString(const char* s)
 {
-    auto it = atomMap.find(s);
-    if (it == atomMap.end()) {
-        AddAtomFixed(s, nextAtom);
-        return nextAtom++;
-    } else
-        return it->second;
+    int atom = LookUpString(s);
+    if (atom == 0) {
+        atom = nextAtom++;
+        AddAtomFixed(s, atom);
+    }
+
+    return atom;
 }
 
 //

glslang/MachineIndependent/preprocessor/PpContext.h

@@ -92,7 +92,7 @@ namespace glslang {
 
 class TPpToken {
 public:
-    TPpToken() : space(false), ival(0), dval(0.0), i64val(0), atom(0)
+    TPpToken() : space(false), ival(0), dval(0.0), i64val(0)
     {
         loc.init(); 
         name[0] = 0;
@@ -112,7 +112,6 @@ public:
     int    ival;
     double dval;
     long long i64val;
-    int    atom;
     char   name[MaxTokenLength + 1];
 };
 
@@ -551,6 +550,7 @@ protected:
     int nextAtom;
     void InitAtomTable();
     void AddAtomFixed(const char* s, int atom);
+    int LookUpString(const char* s);
     int LookUpAddString(const char* s);
     const char* GetAtomString(int atom);
 };

glslang/MachineIndependent/preprocessor/PpScanner.cpp

@@ -247,7 +247,6 @@ int TPpContext::lFloatConst(int len, int ch, TPpToken* ppToken)
 //
 int TPpContext::tStringInput::scan(TPpToken* ppToken)
 {
-    char* tokenText = ppToken->name;
     int AlreadyComplained = 0;
     int len = 0;
     int ch = 0;
@@ -286,7 +285,7 @@ int TPpContext::tStringInput::scan(TPpToken* ppToken)
         case 'z':
             do {
                 if (len < MaxTokenLength) {
-                    tokenText[len++] = (char)ch;
+                    ppToken->name[len++] = (char)ch;
                     ch = getch();
                 } else {
                     if (! AlreadyComplained) {
@@ -304,9 +303,8 @@ int TPpContext::tStringInput::scan(TPpToken* ppToken)
             if (len == 0)
                 continue;
 
-            tokenText[len] = '\0';
+            ppToken->name[len] = '\0';
             ungetch();
-            ppToken->atom = pp->LookUpAddString(tokenText);
             return PpAtomIdentifier;
         case '0':
             ppToken->name[len++] = (char)ch;
@@ -693,13 +691,13 @@ int TPpContext::tStringInput::scan(TPpToken* ppToken)
             ch = getch();
             while (ch != '"' && ch != '\n' && ch != EndOfInput) {
                 if (len < MaxTokenLength) {
-                    tokenText[len] = (char)ch;
+                    ppToken->name[len] = (char)ch;
                     len++;
                     ch = getch();
                 } else
                     break;
             };
-            tokenText[len] = '\0';
+            ppToken->name[len] = '\0';
             if (ch != '"') {
                 ungetch();
                 pp->parseContext.ppError(ppToken->loc, "End of line in string", "string", "");
@@ -821,7 +819,6 @@ int TPpContext::tokenPaste(int token, TPpToken& ppToken)
         if (strlen(ppToken.name) + strlen(pastedPpToken.name) > MaxTokenLength)
             parseContext.ppError(ppToken.loc, "combined tokens are too long", "##", "");
         strncat(ppToken.name, pastedPpToken.name, MaxTokenLength - strlen(ppToken.name));
-        ppToken.atom = LookUpAddString(ppToken.name);
     }
 
     return resultToken;

glslang/MachineIndependent/preprocessor/PpTokens.cpp

@@ -218,7 +218,6 @@ int TPpContext::ReadToken(TokenStream& pTok, TPpToken *ppToken)
 
         switch (ltoken) {
         case PpAtomIdentifier:
-            ppToken->atom = LookUpAddString(ppToken->name);
             break;
         case PpAtomConstString:
             break;

glslang/MachineIndependent/preprocessor/PpTokens.h

@@ -134,7 +134,6 @@ enum EFixedAtoms {
     // preprocessor "keywords"
 
     PpAtomDefine,
-    PpAtomDefined,
     PpAtomUndef,
 
     PpAtomIf,