Working towards functions.. We have parameters and function local types

include/Defs.h

@@ -8,6 +8,7 @@
 #include <stdlib.h>
 #include <ctype.h>
 #include <string.h>
+#include <stdbool.h>
 
 /*
  * ARithmetic tokens are prefixed AR.
@@ -204,7 +205,7 @@ enum StorageScope {
     SC_GLOBAL = 1,  // Global Scope
   //SC_CLASS,       // Class-local definitions
   //SC_STATIC,      // Static storage definitions
-  //SC_PARAM,       // Function parameters
+    SC_PARAM,       // Function parameters
     SC_LOCAL        // Function-local scope.
                     //  There is no deeper scope than function.
 };
@@ -327,6 +328,7 @@ int FindSymbol(char* Symbol);
 
 int AddSymbol(char* Name, int Type, int Structure, int Storage, int EndLabel, int Length);
 
+void FreeLocals();
 
 /* * * * * * * * * * * * * * * * * * * * * * * * * * * *
  * * * *    C O N T R O L       S T A T U S      * * * *
@@ -366,7 +368,7 @@ int AsLdLocalVar(int ID, int Operation);
 int AsStrGlobalVar(int Register, int ID);
 int AsStrLocalVar(int Register, int ID);
 
-int AsCalcOffset(int Type, int Param);
+int AsCalcOffset(int Type);
 void AsNewStackFrame();
 
 int AsDeref(int Reg, int Type);
@@ -422,7 +424,7 @@ void AsFunctionEpilogue(int ID);
  * * * *     D E C L A R A T I O N     * * * *
  * * * * * * * * * * * * * * * * * * * * * * */
 
-void BeginVariableDeclaration(int Type, int Scope);
+void BeginVariableDeclaration(int Type, int Scope, bool isParameter);
 struct ASTNode* ParseIdentifier(void);
 
 struct ASTNode* IfStatement();

src/Assembler.c

@@ -11,7 +11,7 @@
 /*
  * If the entry in UsedRegisters
  *  that correlates to the position of a register in Registers
- *  is 1
+ *   is 1,
  *  then that register is classed as used -
  *   it has useful data inside it.
  * 
@@ -19,9 +19,19 @@
  */
 
 static int UsedRegisters[4];
-static char* Registers[4]       = { "%r8",  "%r9",  "%r10",  "%r11"  };
+/* The https://en.wikipedia.org/wiki/X86_calling_conventions#Microsoft_x64_calling_convention
-static char* DoubleRegisters[4] = { "%r8d", "%r9d", "%r10d", "%r11d" };
+ *  calling convention on Windows requires that
-static char* ByteRegisters[4]   = { "%r8b", "%r9b", "%r10b", "%r11b" };
+ *   the last 4 arguments are placed in registers
+ *   rcx, rdx, r8 and r9.
+ * This order must be preserved, and they must be placed
+ *  right to left.
+ * 
+ * That is the reason for the weird arrangement here.
+ *  The parameter registers are last, in reverse order.
+ */
+static char* Registers[10]       = { "%rsi", "%rdi", "%r10",  "%r11" , "%r12" , "%r13",  "%r9" , "%r8",  "%rdx", "%rcx" };
+static char* DoubleRegisters[10] = { "%esi", "%edi", "%r10d", "%r11d", "%r12d", "%r13d", "%r9d", "%r8d", "%edx", "%ecx" };
+static char* ByteRegisters[10]   = { "%sil", "%dil", "%r10b", "%r11b", "%r12b", "%r13b", "%r9b", "%r8b", "%dl" , "%cl"  };
 
 static char* Comparisons[6]     = { "sete", "setne", "setl", "setg", "setle", "setge" };
 static char* InvComparisons[6]  = { "jne", "je",     "jge",  "jle",  "jg",    "jl"};
@@ -170,7 +180,7 @@ int AssembleTree(struct ASTNode* Node, int Register, int ParentOp) {
 
         case REF_IDENT:
             if(Node->RVal || ParentOp == OP_DEREF) {
-                if(Symbols[Node->Value.ID].Storage == SC_LOCAL)
+                if(Symbols[Node->Value.ID].Storage == SC_LOCAL || Symbols[Node->Value.ID].Storage == SC_PARAM)
                     return AsLdLocalVar(Node->Value.ID, Node->Operation);
                 else 
                     return AsLdGlobalVar(Node->Value.ID, Node->Operation);
@@ -276,7 +286,7 @@ void AsNewStackFrame() {
     LocalVarOffset = 0;
 }
 
-int AsCalcOffset(int Type, int Param) {
+int AsCalcOffset(int Type) {
     LocalVarOffset += PrimitiveSize(Type) > 4 ? PrimitiveSize(Type) : 4;
     return -LocalVarOffset;
 }
@@ -887,8 +897,10 @@ void AssemblerPreamble() {
 
 void AsFunctionPreamble(int FunctionID) {
     char* Name = Symbols[FunctionID].Name;
+    int ParamOffset = 48, ParamReg = 9;
 
-    StackFrameOffset = (LocalVarOffset + 31) & ~31;
+    
+    AsNewStackFrame();
 
     fprintf(OutputFile,
             "\t.text\n"
@@ -896,12 +908,42 @@ void AsFunctionPreamble(int FunctionID) {
             "\t.def\t%s; .scl 2; .type 32; .endef\n"
             "%s:\n"
             "\tpushq\t%%rbp\n"
-            "\tmovq\t%%rsp, %%rbp\n"
+            "\tmovq\t%%rsp, %%rbp\r\n",
-            "\taddq\t$%d, %%rsp\n", Name, Name, Name, -StackFrameOffset);
+            Name, Name, Name);
     
     //PECOFF requires we call the global initialisers
     if(!strcmp(Name, "main"))
         fprintf(OutputFile, "\tcall\t__main\n");
+    
+    // Need to share this between two loops. Fun.
+    int LoopIndex;
+
+    // If we have parameters, move them to the last 4 registers
+    for(LoopIndex = SYMBOLS - 1; LoopIndex > CurrentLocal; LoopIndex--) {
+        if(Symbols[LoopIndex].Storage != SC_PARAM)
+            break;
+        if(LoopIndex < SYMBOLS - 4) // We only have 4 argument registers
+            break;
+
+        Symbols[LoopIndex].SinkOffset = AsCalcOffset(Symbols[LoopIndex].Type);
+        AsStrLocalVar(ParamReg--, LoopIndex);
+    }
+
+    // If we have more parameters, move them to the stack
+    for(; LoopIndex > CurrentLocal; LoopIndex--) {
+        if(Symbols[LoopIndex].Storage == SC_PARAM) {
+            Symbols[LoopIndex].SinkOffset = ParamOffset;
+            ParamOffset += 8;
+        } else {
+            Symbols[LoopIndex].SinkOffset = AsCalcOffset(Symbols[LoopIndex].Type);
+        }
+    }
+
+    // With all the parameters on the stack, we can allocate the shadow space
+    StackFrameOffset = (LocalVarOffset + 31) & ~31;
+    fprintf(OutputFile, 
+            "\taddq\t$%d, %%rsp\n", -StackFrameOffset);
+
 }
 
 void AsFunctionEpilogue(int FunctionID) {

src/Main.c

@@ -13,6 +13,7 @@
 int TypeSizes[9] = { 0,      1,      4,     8,      0,      8,         8,        8,         8}; // in BYTES
 
 char* TokenNames[] = { 
+    "", // Push everything up by one
     "End of file",
     "Equivalency",
 

src/Parser.c

@@ -391,6 +391,7 @@ struct ASTNode* CallFunction() {
 struct ASTNode* ParseStatement(void) {
     int Type;
     
+    printf("\t\tBranch leads to here, type %s/%d\r\n", TokenNames[CurrentToken.type], CurrentToken.type);
     switch(CurrentToken.type) {
         case TY_CHAR:
         case TY_LONG:
@@ -398,7 +399,8 @@ struct ASTNode* ParseStatement(void) {
             printf("\t\tNew Variable: %s\n", CurrentIdentifier);
             Type = ParseOptionalPointer();
             VerifyToken(TY_IDENTIFIER, "ident");
-            BeginVariableDeclaration(Type, SC_LOCAL);
+            BeginVariableDeclaration(Type, SC_LOCAL, false);
+            VerifyToken(LI_SEMIC, ";"); // TODO: single line assignment?
             return NULL;
         
         /*case TY_IDENTIFIER:
@@ -481,9 +483,10 @@ void ParseGlobals() {
             Tree = ParseFunction(Type);
             printf("\nBeginning assembler creation of new function %s\n", Symbols[Tree->Value.ID].Name);
             AssembleTree(Tree, -1, 0);
+            FreeLocals();
         } else {
             printf("\tParsing global variable declaration\n");
-            BeginVariableDeclaration(Type, SC_GLOBAL);
+            BeginVariableDeclaration(Type, SC_GLOBAL, false);
         }
 
         if(CurrentToken.type == LI_EOF)

src/Statements.c

@@ -6,8 +6,31 @@
 
 #include <Defs.h>
 #include <Data.h>
+#include <stdbool.h>
 
+static int ReadParameters() {
+    int TokenType, ParamCount = 0;
 
+    while(CurrentToken.type != LI_RPARE) {
+        TokenType = ParseOptionalPointer();
+        VerifyToken(TY_IDENTIFIER, "identifier");
+
+        BeginVariableDeclaration(TokenType, SC_PARAM, true);
+        ParamCount++;
+
+        switch(CurrentToken.type) {
+            case LI_COM: 
+                Tokenise(&CurrentToken);
+                break;
+            case LI_RPARE:
+                break;
+            default:     
+                DieDecimal("Unexpected token in parameter", CurrentToken.type);
+        }
+    }
+
+    return ParamCount;
+}
 
 /*
  * Handles the declaration of a type of a variable.
@@ -22,7 +45,7 @@
  * //TODO: int i = 5;
  * 
  */
-void BeginVariableDeclaration(int Type, int Scope) {
+void BeginVariableDeclaration(int Type, int Scope, bool isParameter) {
     int ID;
     printf("type: %s\n", TypeNames[Type]);
 
@@ -31,27 +54,34 @@ void BeginVariableDeclaration(int Type, int Scope) {
         //Type = Type - 2;
         if(CurrentToken.type == LI_INT) {
             printf("Adding array %s that is %d x %s.\r\n", CurrentIdentifier, CurrentToken.value, TypeNames[Type]);
-            AddSymbol(CurrentIdentifier, PointerTo(Type), ST_ARR, Scope, 0, CurrentToken.value);
+            if(Scope == SC_LOCAL)
+                Die("Local arrays are not supported");
+            else
+                AddSymbol(CurrentIdentifier, PointerTo(Type), ST_ARR, Scope, 0, CurrentToken.value);
         }
 
         Tokenise(&CurrentToken);
         VerifyToken(LI_RBRAS, "]");
     } else {
         printf("Adding var %s that is a %s\r\n", CurrentIdentifier, TypeNames[Type]);
-        AddSymbol(CurrentIdentifier, Type, ST_VAR, Scope, 0, 1);
+        if(Scope == SC_LOCAL) {
+            if(AddSymbol(CurrentIdentifier, Type, ST_VAR, Scope, 0, 1) == -1)
+                Die("Illegal state: Identical locals in current function");
+        } else {
+            AddSymbol(CurrentIdentifier, Type, ST_VAR, Scope, 0, 1);
+        }
     }
 
-    VerifyToken(LI_SEMIC, ";");
+    //VerifyToken(LI_SEMIC, ";");
 }
 
 struct ASTNode* ParseFunction(int Type) {
     struct ASTNode* Tree;
     struct ASTNode* FinalStatement;
-    int SymbolSlot, BreakLabel;
+    int SymbolSlot, BreakLabel, ParamCount;
-
-    printf("\nIdentified function %s of return type %s\n", CurrentIdentifier, TypeNames[Type]);
 
     BreakLabel = NewLabel();
+    printf("\nIdentified function %s of return type %s, end label %d\n", CurrentIdentifier, TypeNames[Type], BreakLabel);
 
     SymbolSlot = AddSymbol(CurrentIdentifier, Type, ST_FUNC, SC_GLOBAL, BreakLabel, 1);
     CurrentFunction = SymbolSlot;
@@ -59,6 +89,8 @@ struct ASTNode* ParseFunction(int Type) {
     AsNewStackFrame();
 
     VerifyToken(LI_LPARE, "(");
+    ParamCount = ReadParameters();
+    Symbols[SymbolSlot].Length = ParamCount;
     VerifyToken(LI_RPARE, ")");
 
     Tree = ParseCompound();

src/Symbols.c

@@ -22,7 +22,7 @@ int FindSymbolImpl(char* Symbol, int Storage) {
              : SYMBOLS /* Otherwise, start at the end and work backward */ 
               );
                Ind++) {
-
+        if(Storage == SC_GLOBAL && Symbols[Ind].Storage == SC_PARAM) continue; // Skip searching globals for parameters.
         if(*Symbol == *Symbols[Ind].Name && !strcmp(Symbol, Symbols[Ind].Name)) {
             printf("\t\tFound %s at %d\r\n", Symbol, Ind);
             return Ind;
@@ -83,6 +83,15 @@ static int NewLocalSymbol() {
     return Pos;
 }
 
+/*
+ * Reset the local counter on functions.
+ */
+
+void FreeLocals() {
+    CurrentLocal = SYMBOLS - 1;
+}
+
+
 /*
  * Add a symbol to the tables, and set all the metadata.
  *  @param Name:      The string representing the name of the symbol.
@@ -99,19 +108,27 @@ int AddSymbol(char* Name, int Type, int Structure, int Storage, int EndLabel, in
     int TableSlot;
     int SinkOffset = 0;
 
-    if((TableSlot = FindSymbolImpl(Name, Storage) != -1))
+    if((TableSlot = FindSymbolImpl(Name, Storage)) != -1)
-        return TableSlot;
+        return -1;
     
     // Instaed of spliting this up into AddLocalSymbol and AddGlobalSymbol,
     //  we can use this switch to avoid duplicated code.
     switch(Storage) {
+        case SC_PARAM:
+            // Instead of special casing parameters, we can just add these to the symbol lists and be done with it.
+            printf("\tPreparing new parameter %s of type %s\r\n", Name, TypeNames[Type]);
+            TableSlot = AddSymbol(Name, Type, Structure, SC_GLOBAL, 88, 1);
+            Symbols[TableSlot].Storage = SC_PARAM; // Fix the parameter after running the global process
+            TableSlot = AddSymbol(Name, Type, Structure, SC_LOCAL, 88, 1);
+            Symbols[TableSlot].Storage = SC_PARAM; // Fix the parameter after running the local process
+            return TableSlot;
         case SC_GLOBAL:
             TableSlot = NewGlobalSymbol();
             break;
         case SC_LOCAL:
             printf("\tCreating new local symbol %s\r\n", Name);
             TableSlot = NewLocalSymbol();
-            SinkOffset = AsCalcOffset(Type, 0);
+            SinkOffset = AsCalcOffset(Type);
             break;
     }
 
@@ -121,12 +138,13 @@ int AddSymbol(char* Name, int Type, int Structure, int Storage, int EndLabel, in
     Symbols[TableSlot].Storage = Storage;
     Symbols[TableSlot].Length = Length;
     Symbols[TableSlot].SinkOffset = SinkOffset;
+    Symbols[TableSlot].EndLabel = EndLabel;
 
     // NOTE: Generating global symbol names must happen AFTER the name and type are declared.
     switch(Storage) {
         case SC_GLOBAL:
             printf("\tCreating new global symbol %s into slot %d\r\n", Name, TableSlot);
-            if(Structure != ST_FUNC) {
+            if(Structure != ST_FUNC && EndLabel != 88) { // Magic keyword so that we don't generate ASM globals for parameters
                 printf("\t\tGenerating data symbol.\r\n");
                 AsGlobalSymbol(TableSlot);
             }

tests/arguments

@@ -0,0 +1,17 @@
+i32 :: twoparams(int a, i32 b) {
+    int c;
+    int d;
+    int e;
+    c = 3;
+    d = 4;
+    e = 5;
+    PrintInteger(a); PrintInteger(b); PrintInteger(c); PrintInteger(d); PrintInteger(e); 
+    return (0);
+}
+
+int eightparams(int a, int b, int c, int d, int e, int f, int g, int h) {
+    PrintInteger(a); PrintInteger(b); PrintInteger(c); 
+    PrintInteger(d); PrintInteger(e); PrintInteger(f); 
+    PrintInteger(g); PrintInteger(h); 
+    return (0);
+}