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_GPR_POINTER, // A general purpose pointer
147 PO_SFR_REGISTER, // A special function register (e.g. PORTA)
148 PO_PCL, // Program counter Low register
149 PO_PCLATH, // Program counter Latch high register
150 PO_LITERAL, // A constant
151 PO_IMMEDIATE, // (8051 legacy)
152 PO_DIR, // Direct memory (8051 legacy)
153 PO_CRY, // bit memory (8051 legacy)
154 PO_BIT, // bit operand.
155 PO_STR, // (8051 legacy)
157 PO_WILD // Wild card operand in peep optimizer
161 /***********************************************************************
165 * This is not a list of the PIC's opcodes per se, but instead
166 * an enumeration of all of the different types of pic opcodes.
168 ***********************************************************************/
172 POC_WILD=-1, /* Wild card - used in the pCode peep hole optimizer
173 * to represent ANY pic opcode */
226 /***********************************************************************
227 * PC_TYPE - pCode Types
228 ***********************************************************************/
232 PC_COMMENT=0, /* pCode is a comment */
233 PC_INLINE, /* user's inline code */
234 PC_OPCODE, /* PORT dependent opcode */
235 PC_LABEL, /* assembly label */
236 PC_FLOW, /* flow analysis */
237 PC_FUNCTION, /* Function start or end */
238 PC_WILD, /* wildcard - an opcode place holder used
239 * in the pCode peep hole optimizer */
240 PC_CSOURCE, /* C-Source Line */
241 PC_BAD /* Mark the pCode object as being bad */
244 /************************************************/
245 /*************** Structures ********************/
246 /************************************************/
247 /* These are here as forward references - the
248 * full definition of these are below */
250 struct pCodeWildBlock;
251 struct pCodeRegLives;
253 /*************************************************
256 The first step in optimizing pCode is determining
257 the program flow. This information is stored in
258 single-linked lists in the for of 'from' and 'to'
259 objects with in a pcode. For example, most instructions
260 don't involve any branching. So their from branch
261 points to the pCode immediately preceding them and
262 their 'to' branch points to the pcode immediately
263 following them. A skip instruction is an example of
264 a pcode that has multiple (in this case two) elements
265 in the 'to' branch. A 'label' pcode is an where there
266 may be multiple 'from' branches.
267 *************************************************/
269 typedef struct pBranch
271 struct pCode *pc; // Next pCode in a branch
272 struct pBranch *next; /* If more than one branch
273 * the next one is here */
277 /*************************************************
280 pCode Operand structure.
281 For those assembly instructions that have arguments,
282 the pCode will have a pCodeOp in which the argument
283 can be stored. For example
287 'some_register' will be stored/referenced in a pCodeOp
289 *************************************************/
291 typedef struct pCodeOp
298 typedef struct pCodeOpBit
302 unsigned int inBitSpace: 1; /* True if in bit space, else
303 just a bit of a register */
306 typedef struct pCodeOpLit
312 typedef struct pCodeOpImmd
315 int offset; /* low,med, or high byte of immediate value */
316 int index; /* add this to the immediate value */
317 unsigned _const:1; /* is in code space */
318 unsigned _function:1; /* is a (pointer to a) function */
320 int rIdx; /* If this immd points to a register */
321 struct regs *r; /* then this is the reg. */
325 typedef struct pCodeOpLabel
329 int offset; /* low or high byte of label */
332 typedef struct pCodeOpReg
334 pCodeOp pcop; // Can be either GPR or SFR
335 int rIdx; // Index into the register table
337 int instance; // byte # of Multi-byte registers
341 typedef struct pCodeOpRegBit
343 pCodeOpReg pcor; // The Register containing this bit
344 int bit; // 0-7 bit number.
345 PIC_OPTYPE subtype; // The type of this register.
346 unsigned int inBitSpace: 1; /* True if in bit space, else
347 just a bit of a register */
351 typedef struct pCodeOpRegPtr
353 pCodeOpReg pcor; // The Register containing this bit
355 // PIC_OPTYPE subtype; // The type of this register.
356 // unsigned int inBitSpace: 1; /* True if in bit space, else
360 typedef struct pCodeOpWild
364 struct pCodeWildBlock *pcwb;
366 int id; /* index into an array of char *'s that will match
367 * the wild card. The array is in *pcp. */
368 pCodeOp *subtype; /* Pointer to the Operand type into which this wild
369 * card will be expanded */
370 pCodeOp *matched; /* When a wild matches, we'll store a pointer to the
371 * opcode we matched */
376 /*************************************************
379 Here is the basic build block of a PIC instruction.
380 Each pic instruction will get allocated a pCode.
381 A linked list of pCodes makes a program.
383 **************************************************/
389 struct pCode *prev; // The pCode objects are linked together
390 struct pCode *next; // in doubly linked lists.
392 int seq; // sequence number
394 struct pBlock *pb; // The pBlock that contains this pCode.
396 /* "virtual functions"
397 * The pCode structure is like a base class
398 * in C++. The subsequent structures that "inherit"
399 * the pCode structure will initialize these function
400 * pointers to something useful */
401 // void (*analyze) (struct pCode *_this);
402 void (*destruct)(struct pCode *_this);
403 void (*print) (FILE *of,struct pCode *_this);
408 /*************************************************
410 **************************************************/
412 typedef struct pCodeComment
421 /*************************************************
423 **************************************************/
425 typedef struct pCodeCSource
437 /*************************************************
440 The Flow object is used as marker to separate
441 the assembly code into contiguous chunks. In other
442 words, everytime an instruction cause or potentially
443 causes a branch, a Flow object will be inserted into
444 the pCode chain to mark the beginning of the next
447 **************************************************/
449 typedef struct pCodeFlow
454 pCode *end; /* Last pCode in this flow. Note that
455 the first pCode is pc.next */
457 /* set **uses; * map the pCode instruction inCond and outCond conditions
458 * in this array of set's. The reason we allocate an
459 * array of pointers instead of declaring each type of
460 * usage is because there are port dependent usage definitions */
461 //int nuses; /* number of uses sets */
463 set *from; /* flow blocks that can send control to this flow block */
464 set *to; /* flow blocks to which this one can send control */
465 struct pCodeFlow *ancestor; /* The most immediate "single" pCodeFlow object that
466 * executes prior to this one. In many cases, this
467 * will be just the previous */
469 int inCond; /* Input conditions - stuff assumed defined at entry */
470 int outCond; /* Output conditions - stuff modified by flow block */
472 int firstBank; /* The first and last bank flags are the first and last */
473 int lastBank; /* register banks used within one flow object */
478 set *registers;/* Registers used in this flow */
482 /*************************************************
485 The Flow Link object is used to record information
486 about how consecutive excutive Flow objects are related.
487 The pCodeFlow objects demarcate the pCodeInstructions
488 into contiguous chunks. The FlowLink records conflicts
489 in the discontinuities. For example, if one Flow object
490 references a register in bank 0 and the next Flow object
491 references a register in bank 1, then there is a discontinuity
492 in the banking registers.
495 typedef struct pCodeFlowLink
497 pCodeFlow *pcflow; /* pointer to linked pCodeFlow object */
499 int bank_conflict; /* records bank conflicts */
503 /*************************************************
506 Here we describe all the facets of a PIC instruction
507 (expansion for the 18cxxx is also provided).
509 **************************************************/
511 typedef struct pCodeInstruction
516 PIC_OPCODE op; // The opcode of the instruction.
518 char const * const mnemonic; // Pointer to mnemonic string
520 pBranch *from; // pCodes that execute before this one
521 pBranch *to; // pCodes that execute after
522 pBranch *label; // pCode instructions that have labels
524 pCodeOp *pcop; /* Operand, if this instruction has one */
525 pCodeFlow *pcflow; /* flow block to which this instruction belongs */
526 pCodeCSource *cline; /* C Source from which this instruction was derived */
528 unsigned int num_ops; /* Number of operands (0,1,2 for mid range pics) */
529 unsigned int isModReg: 1; /* If destination is W or F, then 1==F */
530 unsigned int isBitInst: 1; /* e.g. BCF */
531 unsigned int isBranch: 1; /* True if this is a branching instruction */
532 unsigned int isSkip: 1; /* True if this is a skip instruction */
533 unsigned int isLit: 1; /* True if this instruction has an literal operand */
535 PIC_OPCODE inverted_op; /* Opcode of instruction that's the opposite of this one */
536 unsigned int inCond; // Input conditions for this instruction
537 unsigned int outCond; // Output conditions for this instruction
542 /*************************************************
544 **************************************************/
546 typedef struct pCodeLabel
556 /*************************************************
558 **************************************************/
560 typedef struct pCodeFunction
566 char *fname; /* If NULL, then this is the end of
567 a function. Otherwise, it's the
568 start and the name is contained
571 pBranch *from; // pCodes that execute before this one
572 pBranch *to; // pCodes that execute after
573 pBranch *label; // pCode instructions that have labels
575 int ncalled; /* Number of times function is called */
580 /*************************************************
582 **************************************************/
584 typedef struct pCodeWild
587 pCodeInstruction pci;
589 int id; /* Index into the wild card array of a peepBlock
590 * - this wild card will get expanded into that pCode
591 * that is stored at this index */
593 /* Conditions on wild pcode instruction */
594 int mustBeBitSkipInst:1;
595 int mustNotBeBitSkipInst:1;
596 int invertBitSkipInst:1;
598 pCodeOp *operand; // Optional operand
599 pCodeOp *label; // Optional label
603 /*************************************************
606 Here are PIC program snippets. There's a strong
607 correlation between the eBBlocks and pBlocks.
608 SDCC subdivides a C program into managable chunks.
609 Each chunk becomes a eBBlock and ultimately in the
612 **************************************************/
614 typedef struct pBlock
616 memmap *cmemmap; /* The snippet is from this memmap */
617 char dbName; /* if cmemmap is NULL, then dbName will identify the block */
618 pCode *pcHead; /* A pointer to the first pCode in a link list of pCodes */
619 pCode *pcTail; /* A pointer to the last pCode in a link list of pCodes */
621 struct pBlock *next; /* The pBlocks will form a doubly linked list */
624 set *function_entries; /* dll of functions in this pblock */
630 unsigned visited:1; /* set true if traversed in call tree */
632 unsigned seq; /* sequence number of this pBlock */
636 /*************************************************
639 The collection of pBlock program snippets are
640 placed into a linked list that is implemented
641 in the pFile structure.
643 The pcode optimizer will parse the pFile.
645 **************************************************/
649 pBlock *pbHead; /* A pointer to the first pBlock */
650 pBlock *pbTail; /* A pointer to the last pBlock */
652 pBranch *functions; /* A SLL of functions in this pFile */
658 /*************************************************
661 The pCodeWildBlock object keeps track of the wild
662 variables, operands, and opcodes that exist in
664 **************************************************/
665 typedef struct pCodeWildBlock {
667 struct pCodePeep *pcp; // pointer back to ... I don't like this...
669 int nvars; // Number of wildcard registers in target.
670 char **vars; // array of pointers to them
672 int nops; // Number of wildcard operands in target.
673 pCodeOp **wildpCodeOps; // array of pointers to the pCodeOp's.
675 int nwildpCodes; // Number of wildcard pCodes in target/replace
676 pCode **wildpCodes; // array of pointers to the pCode's.
680 /*************************************************
683 The pCodePeep object mimics the peep hole optimizer
684 in the main SDCC src (e.g. SDCCpeeph.c). Essentially
685 there is a target pCode chain and a replacement
686 pCode chain. The target chain is compared to the
687 pCode that is generated by gen.c. If a match is
688 found then the pCode is replaced by the replacement
690 **************************************************/
691 typedef struct pCodePeep {
692 pCodeWildBlock target; // code we'd like to optimize
693 pCodeWildBlock replace; // and this is what we'll optimize it with.
696 //pBlock replace; // and this is what we'll optimize it with.
700 /* (Note: a wildcard register is a place holder. Any register
701 * can be replaced by the wildcard when the pcode is being
702 * compared to the target. */
704 /* Post Conditions. A post condition is a condition that
705 * must be either true or false before the peep rule is
706 * accepted. For example, a certain rule may be accepted
707 * if and only if the Z-bit is not used as an input to
708 * the subsequent instructions in a pCode chain.
710 unsigned int postFalseCond;
711 unsigned int postTrueCond;
715 /*************************************************
717 pCode peep command definitions
719 Here are some special commands that control the
720 way the peep hole optimizer behaves
722 **************************************************/
724 enum peepCommandTypes{
731 /*************************************************
732 peepCommand structure stores the peep commands.
734 **************************************************/
736 typedef struct peepCommand {
741 /*************************************************
744 **************************************************/
745 #define PCODE(x) ((pCode *)(x))
746 #define PCI(x) ((pCodeInstruction *)(x))
747 #define PCL(x) ((pCodeLabel *)(x))
748 #define PCF(x) ((pCodeFunction *)(x))
749 #define PCFL(x) ((pCodeFlow *)(x))
750 #define PCFLINK(x)((pCodeFlowLink *)(x))
751 #define PCW(x) ((pCodeWild *)(x))
752 #define PCCS(x) ((pCodeCSource *)(x))
754 #define PCOP(x) ((pCodeOp *)(x))
755 //#define PCOB(x) ((pCodeOpBit *)(x))
756 #define PCOL(x) ((pCodeOpLit *)(x))
757 #define PCOI(x) ((pCodeOpImmd *)(x))
758 #define PCOLAB(x) ((pCodeOpLabel *)(x))
759 #define PCOR(x) ((pCodeOpReg *)(x))
760 #define PCORB(x) ((pCodeOpRegBit *)(x))
761 #define PCOW(x) ((pCodeOpWild *)(x))
763 #define PBR(x) ((pBranch *)(x))
765 #define PCWB(x) ((pCodeWildBlock *)(x))
769 macros for checking pCode types
771 #define isPCI(x) ((PCODE(x)->type == PC_OPCODE))
772 #define isPCI_BRANCH(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isBranch)
773 #define isPCI_SKIP(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isSkip)
774 #define isPCI_LIT(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isLit)
775 #define isPCI_BITSKIP(x)((PCODE(x)->type == PC_OPCODE) && PCI(x)->isSkip && PCI(x)->isBitInst)
776 #define isPCFL(x) ((PCODE(x)->type == PC_FLOW))
777 #define isPCF(x) ((PCODE(x)->type == PC_FUNCTION))
778 #define isPCL(x) ((PCODE(x)->type == PC_LABEL))
779 #define isPCW(x) ((PCODE(x)->type == PC_WILD))
780 #define isPCCS(x) ((PCODE(x)->type == PC_CSOURCE))
782 #define isCALL(x) ((isPCI(x)) && (PCI(x)->op == POC_CALL))
783 #define isSTATUS_REG(r) ((r)->pc_type == PO_STATUS)
785 #define isPCOLAB(x) ((PCOP(x)->type) == PO_LABEL)
787 /*-----------------------------------------------------------------*
789 *-----------------------------------------------------------------*/
791 pCode *newpCode (PIC_OPCODE op, pCodeOp *pcop); // Create a new pCode given an operand
792 pCode *newpCodeCharP(char *cP); // Create a new pCode given a char *
793 pCode *newpCodeInlineP(char *cP); // Create a new pCode given a char *
794 pCode *newpCodeFunction(char *g, char *f); // Create a new function
795 pCode *newpCodeLabel(char *name,int key); // Create a new label given a key
796 pCode *newpCodeCSource(int ln, char *f, char *l); // Create a new symbol line
797 pBlock *newpCodeChain(memmap *cm,char c, pCode *pc); // Create a new pBlock
798 void printpBlock(FILE *of, pBlock *pb); // Write a pBlock to a file
799 void printpCode(FILE *of, pCode *pc); // Write a pCode to a file
800 void addpCode2pBlock(pBlock *pb, pCode *pc); // Add a pCode to a pBlock
801 void addpBlock(pBlock *pb); // Add a pBlock to a pFile
802 void copypCode(FILE *of, char dbName); // Write all pBlocks with dbName to *of
803 void movepBlock2Head(char dbName); // move pBlocks around
804 void AnalyzepCode(char dbName);
805 int OptimizepCode(char dbName);
806 void printCallTree(FILE *of);
807 void pCodePeepInit(void);
808 void pBlockConvert2ISR(pBlock *pb);
810 pCodeOp *newpCodeOpLabel(char *name, int key);
811 pCodeOp *newpCodeOpImmd(char *name, int offset, int index, int code_space,int is_func);
812 pCodeOp *newpCodeOpLit(int lit);
813 pCodeOp *newpCodeOpBit(char *name, int bit,int inBitSpace);
814 pCodeOp *newpCodeOpRegFromStr(char *name);
815 pCodeOp *newpCodeOp(char *name, PIC_OPTYPE p);
816 pCodeOp *pCodeOpCopy(pCodeOp *pcop);
818 pCode * findNextInstruction(pCode *pci);
819 pCode * findNextpCode(pCode *pc, PC_TYPE pct);
820 int isPCinFlow(pCode *pc, pCode *pcflow);
821 struct regs * getRegFromInstruction(pCode *pc);
823 extern void pcode_test(void);
825 /*-----------------------------------------------------------------*
827 *-----------------------------------------------------------------*/
829 extern pCodeOpReg pc_status;
830 extern pCodeOpReg pc_intcon;
831 extern pCodeOpReg pc_indf;
832 extern pCodeOpReg pc_fsr;
833 extern pCodeOpReg pc_pcl;
834 extern pCodeOpReg pc_pclath;
835 extern pCodeOpReg pc_kzero;
836 extern pCodeOpReg pc_wsave; /* wsave, ssave and psave are used to save W, the Status and PCLATH*/
837 extern pCodeOpReg pc_ssave; /* registers during an interrupt */
838 extern pCodeOpReg pc_psave; /* registers during an interrupt */
841 #endif // __PCODE_H__