labels (a5): add labels to everywhere that might be jumped to to simp…

…lify translation (needs more manual validation)
SantriptaSharma · Dec 6, 2023 · ab74829 · ab74829
1 parent a75c394
commit ab74829
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Showing 9 changed files with 89 additions and 15 deletions.
diff --git a/15_A5.y b/15_A5.y
@@ -113,7 +113,7 @@
 
 %%
 /* auxiliary symbols */
-marker: { $$ = quads_size; } // just store the quad index of the next instruction on reduction
+marker: { $$ = quads_size; Emit(JmpLabel()); } // just store the quad index of the next instruction on reduction
 guard: { $$ = MakeList(quads_size); Emit(Jump(AImm(0))); } // emit an unconditional jump, and store a next list to be filled in by rules that use guards
 
 /* expressions */
@@ -467,13 +467,16 @@ conditional_expression:
 
 		$$ = PURE_EXPR(GenTemp());
 		Backpatch($6, quads_size);
+		Emit(JmpLabel());
 		Emit(Mov(ASym($$), ASym($5)));
 		size_t q = quads_size;
 		Emit(Jump(AImm(0)));
 
 		Backpatch($10, quads_size);
+		Emit(JmpLabel());
 		Emit(Mov(ASym($$), ASym($9)));
 		quads[q].rd.imm = quads_size;
+		Emit(JmpLabel());
 	}
 
 assignment_expression:
@@ -681,7 +684,7 @@ compound_statement:
 
 block_item_list:
 	block_item
-	| block_item_list marker block_item { Backpatch($1, $2); $$ = $3; Backpatch($$, quads_size); }
+	| block_item_list marker block_item { Backpatch($1, $2); $$ = $3; Backpatch($$, quads_size); Emit(JmpLabel()); }
 
 block_item:
 	declaration { $$ = NULL; }
@@ -716,12 +719,24 @@ selection_statement:
 	}
 
 iteration_statement:
-	FOR '(' opt_expression ';' marker opt_expression ';' marker opt_expression guard ')' marker statement {
-		QuadList *tl = $6.has_expr ? $6.expr.truelist : NULL;
+	FOR '(' opt_expression ';' marker opt_expression {
+		if (!$6.has_expr) {
+			$6.has_expr = 1;
+			$6.expr = BOOL_EXPR(GenTemp(), MakeList(quads_size), NULL);
+			Emit(Jump(AImm(0)));
+		}
+	} ';' marker opt_expression guard ')' marker statement {
+		QuadList *tl = $6.expr.truelist;
+
+		if (tl == NULL) {
+			tl = MakeList(quads_size);
+			Emit(Jump(AImm(0)));
+		}
+
 		QuadList *fl = $6.has_expr ? $6.expr.falselist : NULL;
 
-		Backpatch(tl, $12); Backpatch($10, $5); Backpatch($13, $8);
-		Emit(Jump(AImm($8)));
+		Backpatch(tl, $13); Backpatch($11, $5); Backpatch($14, $9);
+		Emit(Jump(AImm($9)));
 		$$ = fl;
 	}
 
@@ -734,6 +749,8 @@ jump_statement:
 
 		$$ = NULL;
 
+		Emit(JmpLabel());
+
 		if ($2.has_expr == 1) {
 			Emit(Mov(((Addr){SYMBOL_A, .sym = SymLookup("__retval", 0)}), ASym($2.expr)));
 		}
@@ -788,9 +805,14 @@ function_definition:
 
 		if (quads[quads_size - 1].opcode != RET) {
 			Backpatch($4, quads_size);
+			Emit(JmpLabel());
 			Emit(Return(AImm(0)));
 		} else {
-			Backpatch($4, quads_size - 1);
+			if (quads[quads_size-2].opcode == MOV) {
+				Backpatch($4, quads_size - 3);
+			} else {
+				Backpatch($4, quads_size - 2);
+			}
 		}
 	}
 %%

diff --git a/15_A5_translator.c b/15_A5_translator.c
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include "15_A5_translator.h"
+#include "compiler.h"
 
 extern int yyparse();
 extern void yyerror(char *s);
@@ -10,6 +11,8 @@ const unsigned int size_of_char = 1;
 const unsigned int size_of_int = 4;
 const unsigned int size_of_pointer = 4;
 
+int label_count = 0;
+
 int quads_size = 0, quads_capacity = 64;
 Quad *quads;
 
@@ -231,14 +234,17 @@ void DisplayQuad(Quad q) {
 			DisplayAddr(q.rs);
 		break;
 		case FN_LABEL:
-			printf("%s:", q.rd.sym->name);
+			if (q.rd.kind == SYMBOL_A)
+				printf("%s:", q.rd.sym->name);
+			else
+				printf("_L_%d_:", q.rd.imm);
 		break;
 	}
 }
 
 void DisplayQuads() {
 	for (int i = 0; i < quads_size; i++) {
-		if (quads[i].opcode == FN_LABEL) printf("\n");
+		if (quads[i].opcode == FN_LABEL && quads[i].rd.kind == SYMBOL_A) printf("\n");
 		printf("%d: ", i);
 		DisplayQuad(quads[i]);
 		printf("\n");
@@ -716,6 +722,30 @@ int main() {
 	SymTableDispl(current_table);
 	DisplayQuads();
 
+	char valid = 1;
+
+	// Verify quads: the target of each jump is a label
+	for (int i = 0; i < quads_size; i++) {
+		Quad q = quads[i];
+		if (q.opcode == JMP || q.opcode == JIF || q.opcode == JNT 
+		|| q.opcode == JLT || q.opcode == JGT || q.opcode == JEQ 
+		|| q.opcode == JNE || q.opcode == JLE || q.opcode == JGE) {
+			int ind = q.rd.imm;
+			if (quads[ind].opcode != FN_LABEL) {
+				printf("On quad %d, jump target %d is not a label\n", i, ind);
+				valid = 0;
+			}
+		}
+	}
+
+	if (!valid) {
+		printf("Quads are invalid, aborting\n");
+		FreeTables();
+		FreeQuads();
+		DestroyLists();
+		return 1;
+	}
+
 	// TODO: write quads to file
 	// TODO: append input lib declarations to symbol table
 

diff --git a/15_A5_translator.h b/15_A5_translator.h
@@ -16,6 +16,8 @@ typedef struct _Addr {
 	};
 } Addr;
 
+extern int label_count;
+
 // Used for true, false, and next lists within symbols
 typedef struct _QuadList {
 	int quad_index;
@@ -78,6 +80,7 @@ void Emit(Quad q);
 #define IndexWrite(dest, index, source) ((Quad){INDW, source, index, dest})
 #define DerefWrite(dest, source) ((Quad){PTRW, dest, AImm(0), source})
 #define FnLabel(label) ((Quad){FN_LABEL, AImm(0), AImm(0), label})
+#define JmpLabel() ((Quad){FN_LABEL, AImm(0), AImm(0), AImm(label_count++)})
 
 // Functions for printing a quad & the quads list
 void DisplayQuad(Quad q);

diff --git a/A4_tests/testsimple.nc b/A4_tests/testsimple.nc
@@ -1,5 +1,10 @@
 int GLOB = 1;
 char POPPING_thing = 'c';
+char charithmetic = (POPPING_thing + 'd') - 'c';
+char ithmetic2 = charithmetic - 'd';
+int arithmetic = ithmetic2 + 5;
+char d = +'c';
+char f = -'f';
 
 void printf(char *c, int argv);
 

diff --git a/A5_Tests/test5.nc b/A5_Tests/test5.nc
@@ -1,14 +1,15 @@
 int d = 99;
 
+int * fun2(int b){
+    int * e = 0;
+    return e;
+}
+
 int fun(int c){
     if(c%d == 0) return fun2(c);
     else return fun(c+1);
 }
 
-int * fun2(int b){
-    int * e = 0;
-    return e;
-}
 int main(){
     int a = 1;
     int * ret = fun(a);

diff --git a/Makefile b/Makefile
@@ -18,7 +18,7 @@ build: $(o)
 test: build
 	./$(o) < $(testfile)
 
-$(o): $(fname)_translator.o $(fname).tab.o $(lx).o
+$(o): $(fname)_translator.o $(fname).tab.o $(lx).o compiler.o
 	$(CC) -o $@ $^ $(CFLAGS)
 
 $(lx): lexmain.o $(lx).o

diff --git a/compiler.c b/compiler.c
@@ -0,0 +1,4 @@
+#include <stdio.h>
+
+#include "compiler.h"
+
diff --git a/compiler.h b/compiler.h
@@ -0,0 +1,9 @@
+#ifndef _COMPILER_H_
+#define _COMPILER_H_
+#include "15_A5_translator.h"
+
+extern int quads_size, quads_capacity;
+extern Quad *quads;
+
+
+#endif
diff --git a/createa5.sh b/createa5.sh
@@ -1,3 +1,3 @@
 cp tex_build/15_A5.pdf .
-tar -c 15_A5_translator.c 15_A5_translator.h 15_A5.l 15_A5.nc 15_A5.y Makefile 15_A5.pdf 15_A5_quads* -f 15_A5.tar
+tar -c 15_A5_translator.c 15_A5_translator.h compiler.c compiler.h 15_A5.l 15_A5.nc 15_A5.y Makefile 15_A5.pdf 15_A5_quads* -f 15_A5.tar
 rm 15_A5.pdf