1 /*-------------------------------------------------------------------------
3 pcode.h - post code generation
4 Written By - Scott Dattalo scott@dattalo.com
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 -------------------------------------------------------------------------*/
28 The post code generation is an assembler optimizer. The assembly code
29 produced by all of the previous steps is fully functional. This step
30 will attempt to analyze the flow of the assembly code and agressively
31 optimize it. The peep hole optimizer attempts to do the same thing.
32 As you may recall, the peep hole optimizer replaces blocks of assembly
33 with more optimal blocks (e.g. removing redundant register loads).
34 However, the peep hole optimizer has to be somewhat conservative since
35 an assembly program has implicit state information that's unavailable
36 when only a few instructions are examined.
37 Consider this example:
43 The movf seems redundant since we know that the W register already
44 contains the same value of t1. So a peep hole optimizer is tempted to
45 remove the "movf". However, this is dangerous since the movf affects
46 the flags in the status register (specifically the Z flag) and subsequent
47 code may depend upon this. Look at these two examples:
51 movf t1,w ; Can't remove this movf
57 movf t1,w ; This movf can be removed
58 xorwf t2,w ; since xorwf will over write Z
68 /***********************************************************************
71 * The DFPRINTF macro will call fprintf if PCODE_DEBUG is defined.
72 * The macro is used like:
74 * DPRINTF(("%s #%d\n","test", 1));
76 * The double parenthesis (()) are necessary
78 ***********************************************************************/
82 #define DFPRINTF(args) (fprintf args)
84 #define DFPRINTF(args) ;
88 /***********************************************************************
89 * PIC status bits - this will move into device dependent headers
90 ***********************************************************************/
94 #define PIC_RP0_BIT 5 /* Register Bank select bits RP1:0 : */
95 #define PIC_RP1_BIT 6 /* 00 - bank 0, 01 - bank 1, 10 - bank 2, 11 - bank 3 */
96 #define PIC_IRP_BIT 7 /* Indirect register page select */
98 /***********************************************************************
99 * PIC INTCON bits - this will move into device dependent headers
100 ***********************************************************************/
101 #define PIC_RBIF_BIT 0 /* Port B level has changed flag */
102 #define PIC_INTF_BIT 1 /* Port B bit 0 interrupt on edge flag */
103 #define PIC_T0IF_BIT 2 /* TMR0 has overflowed flag */
104 #define PIC_RBIE_BIT 3 /* Port B level has changed - Interrupt Enable */
105 #define PIC_INTE_BIT 4 /* Port B bit 0 interrupt on edge - Int Enable */
106 #define PIC_T0IE_BIT 5 /* TMR0 overflow Interrupt Enable */
107 #define PIC_PIE_BIT 6 /* Peripheral Interrupt Enable */
108 #define PIC_GIE_BIT 7 /* Global Interrupt Enable */
110 /***********************************************************************
112 ***********************************************************************/
118 /***********************************************************************
120 * PIC_OPTYPE - Operand types that are specific to the PIC architecture
122 * If a PIC assembly instruction has an operand then here is where we
123 * associate a type to it. For example,
127 * The movf has two operands: 'reg' and the W register. 'reg' is some
128 * arbitrary general purpose register, hence it has the type PO_GPR_REGISTER.
129 * The W register, which is the PIC's accumulator, has the type PO_W.
131 ***********************************************************************/
137 PO_NONE=0, // No operand e.g. NOP
138 PO_W, // The 'W' register
139 PO_STATUS, // The 'STATUS' register
140 PO_FSR, // The "file select register" (in 18c it's one of three)
141 PO_INDF, // The Indirect register
142 PO_INTCON, // Interrupt Control register
143 PO_GPR_REGISTER, // A general purpose register
144 PO_GPR_BIT, // A bit of a general purpose register
145 PO_GPR_TEMP, // A general purpose temporary register
146 PO_SFR_REGISTER, // A special function register (e.g. PORTA)
147 PO_PCL, // Program counter Low register
148 PO_PCLATH, // Program counter Latch high register
149 PO_LITERAL, // A constant
150 PO_IMMEDIATE, // (8051 legacy)
151 PO_DIR, // Direct memory (8051 legacy)
152 PO_CRY, // bit memory (8051 legacy)
153 PO_BIT, // bit operand.
154 PO_STR, // (8051 legacy)
156 PO_WILD // Wild card operand in peep optimizer
160 /***********************************************************************
164 * This is not a list of the PIC's opcodes per se, but instead
165 * an enumeration of all of the different types of pic opcodes.
167 ***********************************************************************/
171 POC_WILD=-1, /* Wild card - used in the pCode peep hole optimizer
172 * to represent ANY pic opcode */
225 /***********************************************************************
226 * PC_TYPE - pCode Types
227 ***********************************************************************/
231 PC_COMMENT=0, /* pCode is a comment */
232 PC_INLINE, /* user's inline code */
233 PC_OPCODE, /* PORT dependent opcode */
234 PC_LABEL, /* assembly label */
235 PC_FLOW, /* flow analysis */
236 PC_FUNCTION, /* Function start or end */
237 PC_WILD, /* wildcard - an opcode place holder used
238 * in the pCode peep hole optimizer */
239 PC_CSOURCE, /* C-Source Line */
240 PC_BAD /* Mark the pCode object as being bad */
243 /************************************************/
244 /*************** Structures ********************/
245 /************************************************/
246 /* These are here as forward references - the
247 * full definition of these are below */
249 struct pCodeWildBlock;
250 struct pCodeRegLives;
252 /*************************************************
255 The first step in optimizing pCode is determining
256 the program flow. This information is stored in
257 single-linked lists in the for of 'from' and 'to'
258 objects with in a pcode. For example, most instructions
259 don't involve any branching. So their from branch
260 points to the pCode immediately preceding them and
261 their 'to' branch points to the pcode immediately
262 following them. A skip instruction is an example of
263 a pcode that has multiple (in this case two) elements
264 in the 'to' branch. A 'label' pcode is an where there
265 may be multiple 'from' branches.
266 *************************************************/
268 typedef struct pBranch
270 struct pCode *pc; // Next pCode in a branch
271 struct pBranch *next; /* If more than one branch
272 * the next one is here */
276 /*************************************************
279 pCode Operand structure.
280 For those assembly instructions that have arguments,
281 the pCode will have a pCodeOp in which the argument
282 can be stored. For example
286 'some_register' will be stored/referenced in a pCodeOp
288 *************************************************/
290 typedef struct pCodeOp
297 typedef struct pCodeOpBit
301 unsigned int inBitSpace: 1; /* True if in bit space, else
302 just a bit of a register */
305 typedef struct pCodeOpLit
311 typedef struct pCodeOpImmd
314 int offset; /* low,med, or high byte of immediat value */
315 int index; /* add this to the immediate value */
316 unsigned _const:1; /* is in code space */
318 int rIdx; /* If this immd points to a register */
319 struct regs *r; /* then this is the reg. */
323 typedef struct pCodeOpLabel
329 typedef struct pCodeOpReg
331 pCodeOp pcop; // Can be either GPR or SFR
332 int rIdx; // Index into the register table
334 int instance; // byte # of Multi-byte registers
338 typedef struct pCodeOpRegBit
340 pCodeOpReg pcor; // The Register containing this bit
341 int bit; // 0-7 bit number.
342 PIC_OPTYPE subtype; // The type of this register.
343 unsigned int inBitSpace: 1; /* True if in bit space, else
344 just a bit of a register */
348 typedef struct pCodeOpWild
352 struct pCodeWildBlock *pcwb;
354 int id; /* index into an array of char *'s that will match
355 * the wild card. The array is in *pcp. */
356 pCodeOp *subtype; /* Pointer to the Operand type into which this wild
357 * card will be expanded */
358 pCodeOp *matched; /* When a wild matches, we'll store a pointer to the
359 * opcode we matched */
364 /*************************************************
367 Here is the basic build block of a PIC instruction.
368 Each pic instruction will get allocated a pCode.
369 A linked list of pCodes makes a program.
371 **************************************************/
377 struct pCode *prev; // The pCode objects are linked together
378 struct pCode *next; // in doubly linked lists.
380 int seq; // sequence number
382 struct pBlock *pb; // The pBlock that contains this pCode.
384 /* "virtual functions"
385 * The pCode structure is like a base class
386 * in C++. The subsequent structures that "inherit"
387 * the pCode structure will initialize these function
388 * pointers to something useful */
389 // void (*analyze) (struct pCode *_this);
390 void (*destruct)(struct pCode *_this);
391 void (*print) (FILE *of,struct pCode *_this);
396 /*************************************************
398 **************************************************/
400 typedef struct pCodeComment
409 /*************************************************
411 **************************************************/
413 typedef struct pCodeCSource
425 /*************************************************
428 The Flow object is used as marker to separate
429 the assembly code into contiguous chunks. In other
430 words, everytime an instruction cause or potentially
431 causes a branch, a Flow object will be inserted into
432 the pCode chain to mark the beginning of the next
435 **************************************************/
437 typedef struct pCodeFlow
442 pCode *end; /* Last pCode in this flow. Note that
443 the first pCode is pc.next */
445 /* set **uses; * map the pCode instruction inCond and outCond conditions
446 * in this array of set's. The reason we allocate an
447 * array of pointers instead of declaring each type of
448 * usage is because there are port dependent usage definitions */
449 //int nuses; /* number of uses sets */
451 set *from; /* flow blocks that can send control to this flow block */
452 set *to; /* flow blocks to which this one can send control */
453 struct pCodeFlow *ancestor; /* The most immediate "single" pCodeFlow object that
454 * executes prior to this one. In many cases, this
455 * will be just the previous */
457 int inCond; /* Input conditions - stuff assumed defined at entry */
458 int outCond; /* Output conditions - stuff modified by flow block */
460 int firstBank; /* The first and last bank flags are the first and last */
461 int lastBank; /* register banks used within one flow object */
466 set *registers;/* Registers used in this flow */
470 /*************************************************
473 The Flow Link object is used to record information
474 about how consecutive excutive Flow objects are related.
475 The pCodeFlow objects demarcate the pCodeInstructions
476 into contiguous chunks. The FlowLink records conflicts
477 in the discontinuities. For example, if one Flow object
478 references a register in bank 0 and the next Flow object
479 references a register in bank 1, then there is a discontinuity
480 in the banking registers.
483 typedef struct pCodeFlowLink
485 pCodeFlow *pcflow; /* pointer to linked pCodeFlow object */
487 int bank_conflict; /* records bank conflicts */
491 /*************************************************
494 Here we describe all the facets of a PIC instruction
495 (expansion for the 18cxxx is also provided).
497 **************************************************/
499 typedef struct pCodeInstruction
504 PIC_OPCODE op; // The opcode of the instruction.
506 char const * const mnemonic; // Pointer to mnemonic string
508 pBranch *from; // pCodes that execute before this one
509 pBranch *to; // pCodes that execute after
510 pBranch *label; // pCode instructions that have labels
512 pCodeOp *pcop; /* Operand, if this instruction has one */
513 pCodeFlow *pcflow; /* flow block to which this instruction belongs */
514 pCodeCSource *cline; /* C Source from which this instruction was derived */
516 unsigned int num_ops; /* Number of operands (0,1,2 for mid range pics) */
517 unsigned int isModReg: 1; /* If destination is W or F, then 1==F */
518 unsigned int isBitInst: 1; /* e.g. BCF */
519 unsigned int isBranch: 1; /* True if this is a branching instruction */
520 unsigned int isSkip: 1; /* True if this is a skip instruction */
522 PIC_OPCODE inverted_op; /* Opcode of instruction that's the opposite of this one */
523 unsigned int inCond; // Input conditions for this instruction
524 unsigned int outCond; // Output conditions for this instruction
529 /*************************************************
531 **************************************************/
533 typedef struct pCodeLabel
543 /*************************************************
545 **************************************************/
547 typedef struct pCodeFunction
553 char *fname; /* If NULL, then this is the end of
554 a function. Otherwise, it's the
555 start and the name is contained
558 pBranch *from; // pCodes that execute before this one
559 pBranch *to; // pCodes that execute after
560 pBranch *label; // pCode instructions that have labels
562 int ncalled; /* Number of times function is called */
567 /*************************************************
569 **************************************************/
571 typedef struct pCodeWild
574 pCodeInstruction pci;
576 int id; /* Index into the wild card array of a peepBlock
577 * - this wild card will get expanded into that pCode
578 * that is stored at this index */
580 /* Conditions on wild pcode instruction */
581 int mustBeBitSkipInst:1;
582 int mustNotBeBitSkipInst:1;
583 int invertBitSkipInst:1;
585 pCodeOp *operand; // Optional operand
586 pCodeOp *label; // Optional label
590 /*************************************************
593 Here are PIC program snippets. There's a strong
594 correlation between the eBBlocks and pBlocks.
595 SDCC subdivides a C program into managable chunks.
596 Each chunk becomes a eBBlock and ultimately in the
599 **************************************************/
601 typedef struct pBlock
603 memmap *cmemmap; /* The snippet is from this memmap */
604 char dbName; /* if cmemmap is NULL, then dbName will identify the block */
605 pCode *pcHead; /* A pointer to the first pCode in a link list of pCodes */
606 pCode *pcTail; /* A pointer to the last pCode in a link list of pCodes */
608 struct pBlock *next; /* The pBlocks will form a doubly linked list */
611 set *function_entries; /* dll of functions in this pblock */
617 unsigned visited:1; /* set true if traversed in call tree */
619 unsigned seq; /* sequence number of this pBlock */
623 /*************************************************
626 The collection of pBlock program snippets are
627 placed into a linked list that is implemented
628 in the pFile structure.
630 The pcode optimizer will parse the pFile.
632 **************************************************/
636 pBlock *pbHead; /* A pointer to the first pBlock */
637 pBlock *pbTail; /* A pointer to the last pBlock */
639 pBranch *functions; /* A SLL of functions in this pFile */
645 /*************************************************
648 The pCodeWildBlock object keeps track of the wild
649 variables, operands, and opcodes that exist in
651 **************************************************/
652 typedef struct pCodeWildBlock {
654 struct pCodePeep *pcp; // pointer back to ... I don't like this...
656 int nvars; // Number of wildcard registers in target.
657 char **vars; // array of pointers to them
659 int nops; // Number of wildcard operands in target.
660 pCodeOp **wildpCodeOps; // array of pointers to the pCodeOp's.
662 int nwildpCodes; // Number of wildcard pCodes in target/replace
663 pCode **wildpCodes; // array of pointers to the pCode's.
667 /*************************************************
670 The pCodePeep object mimics the peep hole optimizer
671 in the main SDCC src (e.g. SDCCpeeph.c). Essentially
672 there is a target pCode chain and a replacement
673 pCode chain. The target chain is compared to the
674 pCode that is generated by gen.c. If a match is
675 found then the pCode is replaced by the replacement
677 **************************************************/
678 typedef struct pCodePeep {
679 pCodeWildBlock target; // code we'd like to optimize
680 pCodeWildBlock replace; // and this is what we'll optimize it with.
683 //pBlock replace; // and this is what we'll optimize it with.
687 /* (Note: a wildcard register is a place holder. Any register
688 * can be replaced by the wildcard when the pcode is being
689 * compared to the target. */
691 /* Post Conditions. A post condition is a condition that
692 * must be either true or false before the peep rule is
693 * accepted. For example, a certain rule may be accepted
694 * if and only if the Z-bit is not used as an input to
695 * the subsequent instructions in a pCode chain.
697 unsigned int postFalseCond;
698 unsigned int postTrueCond;
702 /*************************************************
704 pCode peep command definitions
706 Here are some special commands that control the
707 way the peep hole optimizer behaves
709 **************************************************/
711 enum peepCommandTypes{
718 /*************************************************
719 peepCommand structure stores the peep commands.
721 **************************************************/
723 typedef struct peepCommand {
728 /*************************************************
731 **************************************************/
732 #define PCODE(x) ((pCode *)(x))
733 #define PCI(x) ((pCodeInstruction *)(x))
734 #define PCL(x) ((pCodeLabel *)(x))
735 #define PCF(x) ((pCodeFunction *)(x))
736 #define PCFL(x) ((pCodeFlow *)(x))
737 #define PCW(x) ((pCodeWild *)(x))
738 #define PCCS(x) ((pCodeCSource *)(x))
740 #define PCOP(x) ((pCodeOp *)(x))
741 //#define PCOB(x) ((pCodeOpBit *)(x))
742 #define PCOL(x) ((pCodeOpLit *)(x))
743 #define PCOI(x) ((pCodeOpImmd *)(x))
744 #define PCOLAB(x) ((pCodeOpLabel *)(x))
745 #define PCOR(x) ((pCodeOpReg *)(x))
746 #define PCORB(x) ((pCodeOpRegBit *)(x))
747 #define PCOW(x) ((pCodeOpWild *)(x))
749 #define PBR(x) ((pBranch *)(x))
751 #define PCWB(x) ((pCodeWildBlock *)(x))
755 macros for checking pCode types
757 #define isPCI(x) ((PCODE(x)->type == PC_OPCODE))
758 #define isPCI_BRANCH(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isBranch)
759 #define isPCI_SKIP(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isSkip)
760 #define isPCI_BITSKIP(x)((PCODE(x)->type == PC_OPCODE) && PCI(x)->isSkip && PCI(x)->isBitInst)
761 #define isPCFL(x) ((PCODE(x)->type == PC_FLOW))
762 #define isPCF(x) ((PCODE(x)->type == PC_FUNCTION))
763 #define isPCL(x) ((PCODE(x)->type == PC_LABEL))
764 #define isPCW(x) ((PCODE(x)->type == PC_WILD))
765 #define isPCCS(x) ((PCODE(x)->type == PC_CSOURCE))
767 #define isCALL(x) ((isPCI(x)) && (PCI(x)->op == POC_CALL))
768 #define isSTATUS_REG(r) ((r)->pc_type == PO_STATUS)
770 #define isPCOLAB(x) ((PCOP(x)->type) == PO_LABEL)
772 /*-----------------------------------------------------------------*
774 *-----------------------------------------------------------------*/
776 pCode *newpCode (PIC_OPCODE op, pCodeOp *pcop); // Create a new pCode given an operand
777 pCode *newpCodeCharP(char *cP); // Create a new pCode given a char *
778 pCode *newpCodeInlineP(char *cP); // Create a new pCode given a char *
779 pCode *newpCodeFunction(char *g, char *f); // Create a new function
780 pCode *newpCodeLabel(char *name,int key); // Create a new label given a key
781 pCode *newpCodeCSource(int ln, char *f, char *l); // Create a new symbol line
782 pBlock *newpCodeChain(memmap *cm,char c, pCode *pc); // Create a new pBlock
783 void printpBlock(FILE *of, pBlock *pb); // Write a pBlock to a file
784 void printpCode(FILE *of, pCode *pc); // Write a pCode to a file
785 void addpCode2pBlock(pBlock *pb, pCode *pc); // Add a pCode to a pBlock
786 void addpBlock(pBlock *pb); // Add a pBlock to a pFile
787 void copypCode(FILE *of, char dbName); // Write all pBlocks with dbName to *of
788 void movepBlock2Head(char dbName); // move pBlocks around
789 void AnalyzepCode(char dbName);
790 int OptimizepCode(char dbName);
791 void printCallTree(FILE *of);
792 void pCodePeepInit(void);
793 void pBlockConvert2ISR(pBlock *pb);
795 pCodeOp *newpCodeOpLabel(char *name, int key);
796 pCodeOp *newpCodeOpImmd(char *name, int offset, int index, int code_space);
797 pCodeOp *newpCodeOpLit(int lit);
798 pCodeOp *newpCodeOpBit(char *name, int bit,int inBitSpace);
799 pCodeOp *newpCodeOpRegFromStr(char *name);
800 pCodeOp *newpCodeOp(char *name, PIC_OPTYPE p);
801 pCodeOp *pCodeOpCopy(pCodeOp *pcop);
803 pCode * findNextInstruction(pCode *pci);
804 pCode * findNextpCode(pCode *pc, PC_TYPE pct);
805 int isPCinFlow(pCode *pc, pCode *pcflow);
806 struct regs * getRegFromInstruction(pCode *pc);
808 extern void pcode_test(void);
810 /*-----------------------------------------------------------------*
812 *-----------------------------------------------------------------*/
814 extern pCodeOpReg pc_status;
815 extern pCodeOpReg pc_intcon;
816 extern pCodeOpReg pc_indf;
817 extern pCodeOpReg pc_fsr;
818 extern pCodeOpReg pc_pcl;
819 extern pCodeOpReg pc_pclath;
820 extern pCodeOpReg pc_kzero;
821 extern pCodeOpReg pc_wsave; /* wsave and ssave are used to save W and the Status */
822 extern pCodeOpReg pc_ssave; /* registers during an interrupt */
825 #endif // __PCODE_H__