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/*--- begin host_generic_regs.h ---*/
This file is part of Valgrind, a dynamic binary instrumentation
Copyright (C) 2004-2013 OpenWorks LLP
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WITHOUT ANY WARRANTY; without even the implied warranty of
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#include "libvex_basictypes.h"
/*--- Representing HOST REGISTERS ---*/
/* Host registers. Stuff to represent:
- The register index. This is a zero-based, sequential index that
facilitates indexing into arrays or virtual or real registers.
Virtual and real registers both have indices starting at zero.
Interpreting a real register index requires having the host's
RRegUniverse to hand.
- The register's hardware encoding. This applies only for real
registers and should be zero for virtual registers. This is the
number as used in a target architecture encoding.
- The register class
- Whether or not the register is a virtual reg.
Registers are sized so as to fit into 32 bits.
Note that since the class field is never 1111b, no valid register
can have the value INVALID_HREG.
There are currently 6 register classes:
int32 int64 float32 float64 simd64 simd128
/* Registers are represented as 32 bit integers, with the following layout:
31 30..27 26..20 19..0
isV:1 rc:4 enc:7 ix:20
UInt ix:20; // Zero based index
UInt enc:7; // Hardware encoding number
HRegClass rc:4; // the register's HRegClass
Bool isV:1; // is it a virtual register?
The obvious thing to do here would be to use bitfields. But gcc
seems to have problems constant folding calls to mkHReg() with all
4 parameters constant to a 32 bit number, when using bitfields.
Hence the use of the traditional shift-and-mask by-hand bitfields
typedef struct { UInt u32; } HReg;
/* HRegClass describes host register classes which the instruction
selectors can speak about. We would not expect all of them to be
available on any specific host. For example on x86, the available
classes are: Int32, Flt64, Vec128 only.
IMPORTANT NOTE: host_generic_reg_alloc2.c needs how much space is
needed to spill each class of register. It allocates the following
amount of space:
HRcInt32 64 bits
HRcInt64 64 bits
HRcFlt32 64 bits
HRcFlt64 128 bits (on x86 these are spilled by fstpt/fldt and
so won't fit in a 64-bit slot)
HRcVec64 64 bits
HRcVec128 128 bits
If you add another regclass, you must remember to update
host_generic_reg_alloc2.c accordingly.
When adding entries to enum HRegClass, do not use any value > 14 or < 1.
enum {
HRcInt32=3, /* 32-bit int */
HRcInt64=4, /* 64-bit int */
HRcFlt32=5, /* 32-bit float */
HRcFlt64=6, /* 64-bit float */
HRcVec64=7, /* 64-bit SIMD */
HRcVec128=8 /* 128-bit SIMD */
extern void ppHRegClass ( HRegClass );
/* Print an HReg in a generic (non-target-specific) way. */
extern void ppHReg ( HReg );
/* Construct. The goal here is that compiler can fold this down to a
constant in the case where the four arguments are constants, which
is often the case. */
static inline HReg mkHReg ( Bool virtual, HRegClass rc, UInt enc, UInt ix )
vassert(ix <= 0xFFFFF);
vassert(enc <= 0x7F);
vassert(((UInt)rc) <= 0xF);
vassert(((UInt)virtual) <= 1);
if (virtual) vassert(enc == 0);
HReg r;
r.u32 = ((((UInt)virtual) & 1) << 31) |
((((UInt)rc) & 0xF) << 27) |
((((UInt)enc) & 0x7F) << 20) |
((((UInt)ix) & 0xFFFFF) << 0);
return r;
static inline HRegClass hregClass ( HReg r )
HRegClass rc = (HRegClass)((r.u32 >> 27) & 0xF);
vassert(rc >= HRcInt32 && rc <= HRcVec128);
return rc;
static inline UInt hregIndex ( HReg r )
return r.u32 & 0xFFFFF;
static inline UInt hregEncoding ( HReg r )
return (r.u32 >> 20) & 0x7F;
static inline Bool hregIsVirtual ( HReg r )
return toBool((r.u32 >> 31) & 1);
static inline Bool sameHReg ( HReg r1, HReg r2 )
return toBool(r1.u32 == r2.u32);
static const HReg INVALID_HREG = { .u32 = 0xFFFFFFFF };
static inline Bool hregIsInvalid ( HReg r )
return sameHReg(r, INVALID_HREG);
/*--- Real register Universes. ---*/
/* A "Real Register Universe" is a read-only structure that contains
all information about real registers on a given host. It serves
several purposes:
* defines the mapping from real register indices to the registers
* defines the size of the initial section of that mapping that is
available to the register allocator for use, so that the register
allocator can treat the registers under its control as a zero
based, contiguous array. This is important for its efficiency.
* gives meaning to RRegSets, which otherwise would merely be a
bunch of bits.
This is a big structure, but it's readonly, and we expect to
allocate only one instance for each run of Valgrind. It is sized
so as to be able to deal with up to 64 real registers. AFAICS none
of the back ends actually mention more than 64, despite the fact
that many of the host architectures have more than 64 registers
when all classes are taken into consideration.
struct {
/* Total number of registers in this universe .. */
UInt size;
/* .. of which the first |allocable| are available to regalloc. */
UInt allocable;
/* The registers themselves. All must be real registers, and
all must have their index number (.s.ix) equal to the array
index here, since this is the only place where we map index
numbers to actual registers. */
/* Nominally initialise (zero out) an RRegUniverse. */
void RRegUniverse__init ( /*OUT*/RRegUniverse* );
/* Check an RRegUniverse is valid, and assert if not.*/
void RRegUniverse__check_is_sane ( const RRegUniverse* );
/* Print an RRegUniverse, for debugging. */
void RRegUniverse__show ( const RRegUniverse* );
/*--- Real register sets. ---*/
/* Represents sets of real registers. |bitset| is interpreted in the
context of |univ|. That is, each bit index |i| in |bitset|
corresponds to the register |univ->regs[i]|. This relies
entirely on the fact that N_RREGUNIVERSE_REGS <= 64. */
struct {
ULong bitset;
RRegUniverse* univ;
/*--- Recording register usage (for reg-alloc) ---*/
enum { HRmRead, HRmWrite, HRmModify }
/* This isn't entirely general, and is specialised towards being fast,
for the reg-alloc. It represents real registers using a bitmask
and can also represent up to four virtual registers, in an
unordered array. This is based on the observation that no
instruction that we generate can mention more than four registers
at once.
struct {
/* The real registers. The associated universe is not stored
here -- callers will have to pass it around separately, as
needed. */
ULong rRead; /* real regs that are read */
ULong rWritten; /* real regs that are written */
/* The virtual registers. */
UInt n_vRegs;
extern void ppHRegUsage ( const RRegUniverse*, HRegUsage* );
static inline void initHRegUsage ( HRegUsage* tab )
tab->rRead = 0;
tab->rWritten = 0;
tab->n_vRegs = 0;
/* Add a register to a usage table. Combine incoming read uses with
existing write uses into a modify use, and vice versa. Do not
create duplicate entries -- each reg should only be mentioned once.
extern void addHRegUse ( HRegUsage*, HRegMode, HReg );
extern Bool HRegUsage__contains ( const HRegUsage*, HReg );
/*--- Indicating register remappings (for reg-alloc) ---*/
/* Note that such maps can only map virtual regs to real regs.
addToHRegRenap will barf if given a pair not of that form. As a
result, no valid HRegRemap will bind a real reg to anything, and so
if lookupHRegMap is given a real reg, it returns it unchanged.
This is precisely the behaviour that the register allocator needs
to impose its decisions on the instructions it processes. */
#define N_HREG_REMAP 6
struct {
HReg orig [N_HREG_REMAP];
HReg replacement[N_HREG_REMAP];
Int n_used;
extern void ppHRegRemap ( HRegRemap* );
extern void addToHRegRemap ( HRegRemap*, HReg, HReg );
extern HReg lookupHRegRemap ( HRegRemap*, HReg );
static inline void initHRegRemap ( HRegRemap* map )
map->n_used = 0;
/*--- Abstract instructions ---*/
/* A type is needed to refer to pointers to instructions of any
target. Defining it like this means that HInstr* can stand in for
X86Instr*, ArmInstr*, etc. */
typedef void HInstr;
/* An expandable array of HInstr*'s. Handy for insn selection and
register allocation. n_vregs indicates the number of virtual
registers mentioned in the code, something that reg-alloc needs to
know. These are required to be numbered 0 .. n_vregs-1.
struct {
HInstr** arr;
Int arr_size;
Int arr_used;
Int n_vregs;
extern HInstrArray* newHInstrArray ( void );
/* Never call this directly. It's the slow and incomplete path for
addHInstr. */
extern void addHInstr_SLOW ( HInstrArray*, HInstr* );
static inline void addHInstr ( HInstrArray* ha, HInstr* instr )
if (LIKELY(ha->arr_used < ha->arr_size)) {
ha->arr[ha->arr_used] = instr;
} else {
addHInstr_SLOW(ha, instr);
/*--- C-Call return-location descriptions ---*/
/* This is common to all back ends. It describes where the return
value from a C call is located. This is important in the case that
the call is conditional, since the return locations will need to be
set to 0x555..555 in the case that the call does not happen. */
enum {
RLPri_None, /* no return value (a.k.a C "void") */
RLPri_Int, /* in the primary int return reg */
RLPri_2Int, /* in both primary and secondary int ret regs */
RLPri_V128SpRel, /* 128-bit value, on the stack */
RLPri_V256SpRel /* 256-bit value, on the stack */
struct {
/* Primary description */
RetLocPrimary pri;
/* For .pri == RLPri_V128SpRel or RLPri_V256SpRel only, gives
the offset of the lowest addressed byte of the value,
relative to the stack pointer. For all other .how values,
has no meaning and should be zero. */
Int spOff;
extern void ppRetLoc ( RetLoc rloc );
static inline RetLoc mk_RetLoc_simple ( RetLocPrimary pri ) {
vassert(pri >= RLPri_INVALID && pri <= RLPri_2Int);
return (RetLoc){pri, 0};
static inline RetLoc mk_RetLoc_spRel ( RetLocPrimary pri, Int off ) {
vassert(pri >= RLPri_V128SpRel && pri <= RLPri_V256SpRel);
return (RetLoc){pri, off};
static inline Bool is_sane_RetLoc ( RetLoc rloc ) {
switch (rloc.pri) {
case RLPri_None: case RLPri_Int: case RLPri_2Int:
return rloc.spOff == 0;
case RLPri_V128SpRel: case RLPri_V256SpRel:
return True;
return False;
static inline RetLoc mk_RetLoc_INVALID ( void ) {
return (RetLoc){RLPri_INVALID, 0};
static inline Bool is_RetLoc_INVALID ( RetLoc rl ) {
return rl.pri == RLPri_INVALID && rl.spOff == 0;
/*--- Reg alloc: TODO: move somewhere else ---*/
HInstrArray* doRegisterAllocation (
/* Incoming virtual-registerised code. */
HInstrArray* instrs_in,
/* The real-register universe to use. This contains facts about
real registers, one of which is the set of registers available
for allocation. */
const RRegUniverse* univ,
/* Return True iff the given insn is a reg-reg move, in which
case also return the src and dst regs. */
Bool (*isMove) (const HInstr*, HReg*, HReg*),
/* Get info about register usage in this insn. */
void (*getRegUsage) (HRegUsage*, const HInstr*, Bool),
/* Apply a reg-reg mapping to an insn. */
void (*mapRegs) (HRegRemap*, HInstr*, Bool),
/* Return insn(s) to spill/restore a real reg to a spill slot
offset. And optionally a function to do direct reloads. */
void (*genSpill) ( HInstr**, HInstr**, HReg, Int, Bool ),
void (*genReload) ( HInstr**, HInstr**, HReg, Int, Bool ),
HInstr* (*directReload) ( HInstr*, HReg, Short ),
Int guest_sizeB,
/* For debug printing only. */
void (*ppInstr) ( const HInstr*, Bool ),
void (*ppReg) ( HReg ),
/* 32/64bit mode */
Bool mode64
#endif /* ndef __VEX_HOST_GENERIC_REGS_H */
/*--- host_generic_regs.h ---*/