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- /*****************************************************************************
- * Project: dcc
- * File: backend.c
- * Purpose: Back-end module. Generates C code for each procedure.
- * (C) Cristina Cifuentes
- ****************************************************************************/
- #include <cassert>
- #include <string>
- #include "dcc.h"
- #include "disassem.h"
- #include <fstream>
- #include <iostream>
- #include <sstream>
- #include <string.h>
- #include <stdio.h>
- bundle cCode; /* Procedure declaration and code */
- using namespace std;
- /* Returns a unique index to the next label */
- int getNextLabel()
- {
- static int labelIdx = 1; /* index of the next label */
- return (labelIdx++);
- }
- /* displays statistics on the subroutine */
- void Function::displayStats ()
- {
- printf("\nStatistics - Subroutine %s\n", name.c_str());
- printf ("Number of Icode instructions:\n");
- printf (" Low-level : %4d\n", stats.numLLIcode);
- if (! (flg & PROC_ASM))
- {
- printf (" High-level: %4d\n", stats.numHLIcode);
- printf (" Percentage reduction: %2.2f%%\n", 100.0 - (stats.numHLIcode *
- 100.0) / stats.numLLIcode);
- }
- }
- /**** this proc is not required any more?? ****/
- #if 0
- static void fixupLabels (PPROC pProc)
- /* Checks the graph (pProc->cfg) for any nodes that have labels, and gives
- * a unique label number for it. This label is placed in the associated
- * icode for the node (pProc->Icode). The procedure is done in sequential
- * order of dsfLast numbering. */
- { int i; /* index into the dfsLast array */
- PBB *dfsLast; /* pointer to the dfsLast array */
- dfsLast = pProc->dfsLast;
- for (i = 0; i < pProc->numBBs; i++)
- if (dfsLast[i]->flg/* & BB_HAS_LABEL*/) {
- pProc->Icode.icode[dfsLast[i]->start].ll()->flg |= HLL_LABEL;
- pProc->Icode.icode[dfsLast[i]->start].ll()->hllLabNum = getNextLabel();
- }
- }
- #endif
- /* Returns the corresponding C string for the given character c. Character
- * constants such as carriage return and line feed, require 2 C characters. */
- char *cChar (uint8_t c)
- {
- static char res[3];
- switch (c) {
- case 0x8: /* backspace */
- sprintf (res, "\\b");
- break;
- case 0x9: /* horizontal tab */
- sprintf (res, "\\t");
- break;
- case 0x0A: /* new line */
- sprintf (res, "\\n");
- break;
- case 0x0C: /* form feed */
- sprintf (res, "\\f");
- break;
- case 0x0D: /* carriage return */
- sprintf (res, "\\r");
- break;
- default: /* any other character*/
- sprintf (res, "%c", c);
- }
- return (res);
- }
- /* Prints the variable's name and initial contents on the file.
- * Note: to get to the value of the variable:
- * com file: prog.Image[operand]
- * exe file: prog.Image[operand+0x100] */
- static void printGlobVar (SYM * psym)
- {
- int j;
- uint32_t relocOp = prog.fCOM ? psym->label : psym->label + 0x100;
- switch (psym->size)
- {
- case 1: cCode.appendDecl( "uint8_t\t%s = %ld;\n",
- psym->name, prog.Image[relocOp]);
- break;
- case 2: cCode.appendDecl( "uint16_t\t%s = %ld;\n",
- psym->name, LH(prog.Image+relocOp));
- break;
- case 4: if (psym->type == TYPE_PTR) /* pointer */
- cCode.appendDecl( "uint16_t\t*%s = %ld;\n",
- psym->name, LH(prog.Image+relocOp));
- else /* char */
- cCode.appendDecl(
- "char\t%s[4] = \"%c%c%c%c\";\n",
- psym->name, prog.Image[relocOp],
- prog.Image[relocOp+1], prog.Image[relocOp+2],
- prog.Image[relocOp+3]);
- break;
- default:
- {
- ostringstream strContents;
- for (j=0; j < psym->size; j++)
- strContents << cChar(prog.Image[relocOp + j]);
- cCode.appendDecl( "char\t*%s = \"%s\";\n", psym->name, strContents.str().c_str());
- }
- }
- }
- // Note: Not called at present.
- /* Writes the contents of the symbol table, along with any variable
- * initialization. */
- static void writeGlobSymTable()
- {
- char type[10];
- if (not symtab.empty())
- {
- cCode.appendDecl( "/* Global variables */\n");
- for (SYM &sym : symtab)
- {
- if (sym.duVal.isUSE_VAL()) /* first used */
- printGlobVar (&sym);
- else { /* first defined */
- switch (sym.size) {
- case 1: strcpy (type, "uint8_t\t"); break;
- case 2: strcpy (type, "int\t"); break;
- case 4: if (sym.type == TYPE_PTR)
- strcpy (type, "int\t*");
- else
- strcpy (type, "char\t*");
- break;
- default: strcpy (type, "char\t*");
- }
- cCode.appendDecl( "%s%s;\t/* size = %ld */\n",
- type, sym.name, sym.size);
- }
- }
- cCode.appendDecl( "\n");
- }
- }
- /* Writes the header information and global variables to the output C file
- * fp. */
- static void writeHeader (std::ostream &_ios, char *fileName)
- {
- /* Write header information */
- newBundle (&cCode);
- cCode.appendDecl( "/*\n");
- cCode.appendDecl( " * Input file\t: %s\n", fileName);
- cCode.appendDecl( " * File type\t: %s\n", (prog.fCOM)?"COM":"EXE");
- cCode.appendDecl( " */\n\n#include \"dcc.h\"\n\n");
- /* Write global symbol table */
- /** writeGlobSymTable(); *** need to change them into locident fmt ***/
- writeBundle (_ios, cCode);
- freeBundle (&cCode);
- }
- // Note: Not currently called!
- /* Checks the given icode to determine whether it has a label associated
- * to it. If so, a goto is emitted to this label; otherwise, a new label
- * is created and a goto is also emitted.
- * Note: this procedure is to be used when the label is to be forward on
- * the code; that is, the target code has not been traversed yet. */
- static void emitFwdGotoLabel (ICODE * pt, int indLevel)
- {
- if ( not pt->ll()->testFlags(HLL_LABEL)) /* node hasn't got a lab */
- {
- /* Generate new label */
- pt->ll()->hllLabNum = getNextLabel();
- pt->ll()->setFlags(HLL_LABEL);
- }
- cCode.appendCode( "%sgoto l%ld;\n", indentStr(indLevel), pt->ll()->hllLabNum);
- }
- /* Writes the procedure's declaration (including arguments), local variables,
- * and invokes the procedure that writes the code of the given record *hli */
- void Function::codeGen (std::ostream &fs)
- {
- int numLoc;
- ostringstream buf;
- //STKFRAME * args; /* Procedure arguments */
- //char buf[200], /* Procedure's definition */
- // arg[30]; /* One argument */
- BB *pBB; /* Pointer to basic block */
- /* Write procedure/function header */
- newBundle (&cCode);
- if (flg & PROC_IS_FUNC) /* Function */
- cCode.appendDecl( "\n%s %s (", hlTypes[retVal.type],name.c_str());
- else /* Procedure */
- cCode.appendDecl( "\nvoid %s (", name.c_str());
- /* Write arguments */
- for (size_t i = 0; i < args.sym.size(); i++)
- {
- if (args.sym[i].invalid == FALSE)
- {
- buf<<hlTypes[args.sym[i].type]<<" "<<args.sym[i].name;
- if (i < (args.sym.size() - 1))
- buf<<", ";
- }
- }
- buf<<")\n";
- cCode.appendDecl( buf.str() );
- /* Write comments */
- writeProcComments();
- /* Write local variables */
- if (! (flg & PROC_ASM))
- {
- numLoc = 0;
- for (ID &refId : localId )
- {
- /* Output only non-invalidated entries */
- if (refId.illegal == FALSE)
- {
- if (refId.loc == REG_FRAME)
- {
- /* Register variables are assigned to a local variable */
- if (((flg & SI_REGVAR) && (refId.id.regi == rSI)) ||
- ((flg & DI_REGVAR) && (refId.id.regi == rDI)))
- {
- sprintf (refId.name, "loc%ld", ++numLoc);
- cCode.appendDecl( "int %s;\n", refId.name);
- }
- /* Other registers are named when they are first used in
- * the output C code, and appended to the proc decl. */
- }
- else if (refId.loc == STK_FRAME)
- {
- /* Name local variables and output appropriate type */
- sprintf (refId.name, "loc%ld", ++numLoc);
- cCode.appendDecl( "%s %s;\n",hlTypes[refId.type], refId.name);
- }
- }
- }
- }
- /* Write procedure's code */
- if (flg & PROC_ASM) /* generate assembler */
- disassem (3, this);
- else /* generate C */
- {
- m_cfg.front()->writeCode (1, this, &numLoc, MAX, UN_INIT);
- }
- cCode.appendCode( "}\n\n");
- writeBundle (fs, cCode);
- freeBundle (&cCode);
- /* Write Live register analysis information */
- if (option.verbose)
- for (size_t i = 0; i < numBBs; i++)
- {
- pBB = m_dfsLast[i];
- if (pBB->flg & INVALID_BB) continue; /* skip invalid BBs */
- cout << "BB "<<i<<"\n";
- cout << " Start = "<<pBB->begin()->loc_ip;
- cout << ", end = "<<pBB->begin()->loc_ip+pBB->size()<<"\n";
- cout << " LiveUse = ";
- Machine_X86::writeBitVector(cout,pBB->liveUse);
- cout << "\n Def = ";
- Machine_X86::writeBitVector(cout,pBB->def);
- cout << "\n LiveOut = ";
- Machine_X86::writeBitVector(cout,pBB->liveOut);
- cout << "\n LiveIn = ";
- Machine_X86::writeBitVector(cout,pBB->liveIn);
- cout <<"\n\n";
- }
- }
- /* Recursive procedure. Displays the procedure's code in depth-first order
- * of the call graph. */
- static void backBackEnd (char *filename, CALL_GRAPH * pcallGraph, std::ostream &_ios)
- {
- // IFace.Yield(); /* This is a good place to yield to other apps */
- /* Check if this procedure has been processed already */
- if ((pcallGraph->proc->flg & PROC_OUTPUT) ||
- (pcallGraph->proc->flg & PROC_ISLIB))
- return;
- pcallGraph->proc->flg |= PROC_OUTPUT;
- /* Dfs if this procedure has any successors */
- for (size_t i = 0; i < pcallGraph->outEdges.size(); i++)
- {
- backBackEnd (filename, pcallGraph->outEdges[i], _ios);
- }
- /* Generate code for this procedure */
- stats.numLLIcode = pcallGraph->proc->Icode.size();
- stats.numHLIcode = 0;
- pcallGraph->proc->codeGen (_ios);
- /* Generate statistics */
- if (option.Stats)
- pcallGraph->proc->displayStats ();
- if (! (pcallGraph->proc->flg & PROC_ASM))
- {
- stats.totalLL += stats.numLLIcode;
- stats.totalHL += stats.numHLIcode;
- }
- }
- /* Invokes the necessary routines to produce code one procedure at a time. */
- void BackEnd (char *fileName, CALL_GRAPH * pcallGraph)
- {
- std::ofstream fs; /* Output C file */
- /* Get output file name */
- std::string outNam(fileName);
- outNam = outNam.substr(0,outNam.rfind("."))+".b"; /* b for beta */
- /* Open output file */
- fs.open(outNam);
- if(!fs.is_open())
- fatalError (CANNOT_OPEN, outNam.c_str());
- printf ("dcc: Writing C beta file %s\n", outNam.c_str());
- /* Header information */
- writeHeader (fs, fileName);
- /* Initialize total Icode instructions statistics */
- stats.totalLL = 0;
- stats.totalHL = 0;
- /* Process each procedure at a time */
- backBackEnd (fileName, pcallGraph, fs);
- /* Close output file */
- fs.close();
- printf ("dcc: Finished writing C beta file\n");
- }
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