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Rework the routines that convert AP[S]Int into a string. Now, instead of

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returning an std::string by value, it fills in a SmallString/SmallVector
passed in.  This significantly reduces string thrashing in some cases.

More specifically, this:
 - Adds an operator<< and a print method for APInt that allows you to 
   directly send them to an ostream.
 - Reimplements APInt::toString to be much simpler and more efficient
   algorithmically in addition to not thrashing strings quite as much.

This speeds up llvm-dis on kc++ by 7%, and may also slightly speed up the
asmprinter.  This also fixes a bug I introduced into the asmwriter in a
previous patch w.r.t. alias printing.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54873 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2008-08-17 07:19:36 +00:00
parent b6c8a4098f
commit fad86b003a
13 changed files with 170 additions and 140 deletions
Download Patch File Download Diff File Expand all files Collapse all files

195
lib/Support/APInt.cpp
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@ -15,14 +15,13 @@
#define DEBUG_TYPE "apint"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include <math.h>
#include <cmath>
#include <limits>
#include <cstring>
#include <cstdlib>
#include <iomanip>
using namespace llvm;
/// This enumeration just provides for internal constants used in this
@ -1478,12 +1477,14 @@ static void KnuthDiv(uint32_t *u, uint32_t *v, uint32_t *q, uint32_t* r,
// is 2^31 so we just set it to -1u.
uint64_t b = uint64_t(1) << 32;
#if 0
DEBUG(cerr << "KnuthDiv: m=" << m << " n=" << n << '\n');
DEBUG(cerr << "KnuthDiv: original:");
DEBUG(for (int i = m+n; i >=0; i--) cerr << " " << std::setbase(16) << u[i]);
DEBUG(cerr << " by");
DEBUG(for (int i = n; i >0; i--) cerr << " " << std::setbase(16) << v[i-1]);
DEBUG(cerr << '\n');
#endif
// D1. [Normalize.] Set d = b / (v[n-1] + 1) and multiply all the digits of
// u and v by d. Note that we have taken Knuth's advice here to use a power
// of 2 value for d such that d * v[n-1] >= b/2 (b is the base). A power of
@ -1508,11 +1509,13 @@ static void KnuthDiv(uint32_t *u, uint32_t *v, uint32_t *q, uint32_t* r,
}
}
u[m+n] = u_carry;
#if 0
DEBUG(cerr << "KnuthDiv: normal:");
DEBUG(for (int i = m+n; i >=0; i--) cerr << " " << std::setbase(16) << u[i]);
DEBUG(cerr << " by");
DEBUG(for (int i = n; i >0; i--) cerr << " " << std::setbase(16) << v[i-1]);
DEBUG(cerr << '\n');
#endif
// D2. [Initialize j.] Set j to m. This is the loop counter over the places.
int j = m;
@ -1636,7 +1639,9 @@ static void KnuthDiv(uint32_t *u, uint32_t *v, uint32_t *q, uint32_t* r,
}
DEBUG(cerr << '\n');
}
#if 0
DEBUG(cerr << std::setbase(10) << '\n');
#endif
}
void APInt::divide(const APInt LHS, uint32_t lhsWords,
@ -2001,114 +2006,112 @@ void APInt::fromString(uint32_t numbits, const char *str, uint32_t slen,
}
}
std::string APInt::toString(uint8_t radix, bool wantSigned) const {
assert((radix == 10 || radix == 8 || radix == 16 || radix == 2) &&
void APInt::toString(SmallVectorImpl<char> &Str, unsigned Radix,
bool Signed) const {
assert((Radix == 10 || Radix == 8 || Radix == 16 || Radix == 2) &&
"Radix should be 2, 8, 10, or 16!");
static const char *const digits[] = {
"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"
};
std::string result;
uint32_t bits_used = getActiveBits();
// First, check for a zero value and just short circuit the logic below.
if (*this == 0) {
Str.push_back('0');
return;
}
static const char Digits[] = "0123456789ABCDEF";
if (isSingleWord()) {
char buf[65];
const char *format = (radix == 10 ? (wantSigned ? "%lld" : "%llu") :
(radix == 16 ? "%llX" : (radix == 8 ? "%llo" : 0)));
if (format) {
if (wantSigned) {
int64_t sextVal = (int64_t(VAL) << (APINT_BITS_PER_WORD-BitWidth)) >>
(APINT_BITS_PER_WORD-BitWidth);
sprintf(buf, format, sextVal);
} else
sprintf(buf, format, VAL);
char Buffer[65];
char *BufPtr = Buffer+65;
uint64_t N;
if (Signed) {
int64_t I = getSExtValue();
if (I < 0) {
Str.push_back('-');
I = -I;
}
N = I;
} else {
memset(buf, 0, 65);
uint64_t v = VAL;
while (bits_used) {
uint32_t bit = (uint32_t)v & 1;
bits_used--;
buf[bits_used] = digits[bit][0];
v >>=1;
}
N = getZExtValue();
}
result = buf;
return result;
while (N) {
*--BufPtr = Digits[N % Radix];
N /= Radix;
}
Str.append(BufPtr, Buffer+65);
return;
}
if (radix != 10) {
// For the 2, 8 and 16 bit cases, we can just shift instead of divide
// because the number of bits per digit (1,3 and 4 respectively) divides
// equaly. We just shift until there value is zero.
// First, check for a zero value and just short circuit the logic below.
if (*this == 0)
result = "0";
else {
APInt tmp(*this);
size_t insert_at = 0;
if (wantSigned && this->isNegative()) {
// They want to print the signed version and it is a negative value
// Flip the bits and add one to turn it into the equivalent positive
// value and put a '-' in the result.
tmp.flip();
tmp++;
result = "-";
insert_at = 1;
}
// Just shift tmp right for each digit width until it becomes zero
uint32_t shift = (radix == 16 ? 4 : (radix == 8 ? 3 : 1));
uint64_t mask = radix - 1;
APInt zero(tmp.getBitWidth(), 0);
while (tmp.ne(zero)) {
unsigned digit =
(unsigned)((tmp.isSingleWord() ? tmp.VAL : tmp.pVal[0]) & mask);
result.insert(insert_at, digits[digit]);
tmp = tmp.lshr(shift);
}
}
return result;
}
APInt tmp(*this);
APInt divisor(4, radix);
APInt zero(tmp.getBitWidth(), 0);
size_t insert_at = 0;
if (wantSigned && tmp[BitWidth-1]) {
APInt Tmp(*this);
if (Signed && isNegative()) {
// They want to print the signed version and it is a negative value
// Flip the bits and add one to turn it into the equivalent positive
// value and put a '-' in the result.
tmp.flip();
tmp++;
result = "-";
insert_at = 1;
Tmp.flip();
Tmp++;
Str.push_back('-');
}
if (tmp == zero)
result = "0";
else while (tmp.ne(zero)) {
APInt APdigit(1,0);
APInt tmp2(tmp.getBitWidth(), 0);
divide(tmp, tmp.getNumWords(), divisor, divisor.getNumWords(), &tmp2,
&APdigit);
uint32_t digit = (uint32_t)APdigit.getZExtValue();
assert(digit < radix && "divide failed");
result.insert(insert_at,digits[digit]);
tmp = tmp2;
// We insert the digits backward, then reverse them to get the right order.
unsigned StartDig = Str.size();
// For the 2, 8 and 16 bit cases, we can just shift instead of divide
// because the number of bits per digit (1, 3 and 4 respectively) divides
// equaly. We just shift until the value is zero.
if (Radix != 10) {
// Just shift tmp right for each digit width until it becomes zero
unsigned ShiftAmt = (Radix == 16 ? 4 : (Radix == 8 ? 3 : 1));
unsigned MaskAmt = Radix - 1;
while (Tmp != 0) {
unsigned Digit = unsigned(Tmp.getRawData()[0]) & MaskAmt;
Str.push_back(Digits[Digit]);
Tmp = Tmp.lshr(ShiftAmt);
}
} else {
APInt divisor(4, 10);
while (Tmp != 0) {
APInt APdigit(1, 0);
APInt tmp2(Tmp.getBitWidth(), 0);
divide(Tmp, Tmp.getNumWords(), divisor, divisor.getNumWords(), &tmp2,
&APdigit);
uint32_t Digit = (uint32_t)APdigit.getZExtValue();
assert(Digit < Radix && "divide failed");
Str.push_back(Digits[Digit]);
Tmp = tmp2;
}
}
return result;
// Reverse the digits before returning.
std::reverse(Str.begin()+StartDig, Str.end());
}
void APInt::dump() const
{
cerr << "APInt(" << BitWidth << ")=" << std::setbase(16);
if (isSingleWord())
cerr << VAL;
else for (unsigned i = getNumWords(); i > 0; i--) {
cerr << pVal[i-1] << " ";
}
cerr << " U(" << this->toStringUnsigned(10) << ") S("
<< this->toStringSigned(10) << ")" << std::setbase(10);
/// toString - This returns the APInt as a std::string. Note that this is an
/// inefficient method. It is better to pass in a SmallVector/SmallString
/// to the methods above.
std::string APInt::toString(unsigned Radix = 10, bool Signed = true) const {
SmallString<40> S;
toString(S, Radix, Signed);
return S.c_str();
}
void APInt::dump() const {
SmallString<40> S, U;
this->toStringUnsigned(U);
this->toStringSigned(S);
fprintf(stderr, "APInt(%db, %su %ss)", BitWidth, U.c_str(), S.c_str());
}
void APInt::print(std::ostream &OS, bool isSigned) const {
SmallString<40> S;
this->toString(S, 10, isSigned);
OS << S.c_str();
}
// This implements a variety of operations on a representation of
// arbitrary precision, two's-complement, bignum integer values.