summaryrefslogtreecommitdiff
path: root/lib/VMCore/getValue.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/VMCore/getValue.cpp')
-rw-r--r--lib/VMCore/getValue.cpp474
1 files changed, 474 insertions, 0 deletions
diff --git a/lib/VMCore/getValue.cpp b/lib/VMCore/getValue.cpp
new file mode 100644
index 0000000000..2eae584402
--- /dev/null
+++ b/lib/VMCore/getValue.cpp
@@ -0,0 +1,474 @@
+//===-- Use.cpp - Implement the Use class ---------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the algorithm for finding the User of a Use.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/User.h"
+// this can later be removed:
+#include <iostream>
+
+namespace llvm {
+
+class Use::UseWaymark {
+
+ friend class Use;
+
+enum { spareBits = 2, requiredSteps = sizeof(Value*) * 8 - spareBits };
+
+/// repaintByCopying -- given a pattern and a
+/// junk tagspace, copy the former's tags into
+/// the latter
+///
+static inline void repaintByCopying(Use *Tagspace, Use *Junk) {
+ for (int I = requiredSteps; I; --I) {
+ Use *Next = stripTag<Use::tagMaskN>(Junk->Next);
+ Junk->Next = transferTag<Use::tagMaskN>(Tagspace->Next, Next);
+ Tagspace = stripTag<Use::tagMaskN>(Tagspace->Next);
+ Junk = Next;
+ }
+
+ assert((extractTag<Use::NextPtrTag, Use::tagMaskN>(Junk->Next) == Use::stopTagN)
+ && "Why repaint by copying if the next is not Stop?");
+}
+
+
+/// repaintByCalculating -- given a pattern and a
+/// junk tagspace, compute tags into the latter
+///
+static inline void repaintByCalculating(unsigned long Tags, Use *Junk) {
+ Tags >>= spareBits;
+
+ for (int I = requiredSteps - 1; I >= 0; --I) {
+ Use::NextPtrTag Tag(Tags & (1 << I) ? Use::oneDigitTagN : Use::zeroDigitTagN);
+ Use *Next = stripTag<Use::tagMaskN>(Junk->Next);
+ Junk->Next = transferTag<Use::tagMaskN>(reinterpret_cast<Use*>(Tag), Next);
+ Junk = Next;
+ }
+
+ assert((extractTag<Use::NextPtrTag, Use::tagMaskN>(Junk->Next) == Use::fullStopTagN)
+ && "Why repaint by calculating if the next is not FullStop?");
+}
+
+/// punchAwayDigits -- ensure that repainted area
+/// begins with a stop
+///
+static inline void punchAwayDigits(Use **Uprev) {
+ Uprev = stripTag<Use::tagMask>(Uprev);
+ // if (PrevU)
+ // assert(&PrevU->Next == Uprev && "U->Prev differs from PrevU?");
+ *Uprev = stripTag<Use::tagMaskN>(*Uprev);
+}
+
+
+/// gatherAndPotentiallyRepaint is invoked for either
+/// - sweeping over (a small amount of) initial junk
+/// - or sweeping over a great amount of junk which
+/// provides enough space to reproduce the bit pattern
+/// of the Value* at its end, in which case it gets
+/// overpainted.
+/// In any case this routine is invoked with U being
+/// pointed at from a Use with a stop tag.
+///
+static inline Value *gatherAndPotentiallyRepaint(Use *U) {
+ int Cushion = requiredSteps;
+
+ Use *Next(U->Next);
+ // __builtin_prefetch(Next);
+ Use::NextPtrTag Tag(extractTag<Use::NextPtrTag, Use::tagMaskN>(Next));
+ Next = stripTag<Use::tagMaskN>(Next);
+
+ // try to pick up exactly requiredSteps digits
+ // from immediately behind the (precondition) stop
+ unsigned long Acc(0);
+ while (1) {
+ if (Cushion <= 0) {
+ assert((Tag == Use::fullStopTagN || Tag == Use::stopTagN)
+ && "More digits?");
+ return reinterpret_cast<Value*>(Acc << spareBits);
+ }
+
+ switch (Tag) {
+ case Use::fullStopTagN:
+ return reinterpret_cast<Value*>(Next);
+ case Use::stopTagN: {
+ goto efficiency;
+ }
+ default:
+ Acc = (Acc << 1) | (Tag & 1);
+ Next = Next->Next;
+ // __builtin_prefetch(Next);
+ --Cushion;
+ Tag = extractTag<Use::NextPtrTag, Use::tagMaskN>(Next);
+ Next = stripTag<Use::tagMaskN>(Next);
+ continue;
+ }
+ break;
+ }
+
+ while (Cushion > 0) {
+ switch (Tag) {
+ case Use::fullStopTagN:
+ return reinterpret_cast<Value*>(Next);
+ case Use::stopTagN: {
+ efficiency:
+ // try to pick up exactly requiredSteps digits
+ int digits = requiredSteps;
+ Acc = 0;
+
+ while (1) {
+ if (!digits)
+ return reinterpret_cast<Value*>(Acc << spareBits);
+
+ Next = Next->Next;
+ // __builtin_prefetch(Next);
+ --Cushion;
+ Tag = extractTag<Use::NextPtrTag, Use::tagMaskN>(Next);
+ Next = stripTag<Use::tagMaskN>(Next);
+ switch (Tag) {
+ case Use::fullStopTagN:
+ if (Cushion <= 0) {
+ punchAwayDigits(U->Prev);
+ repaintByCalculating(reinterpret_cast<unsigned long>(Next), U);
+ }
+ return reinterpret_cast<Value*>(Next);
+ case Use::stopTagN: {
+ if (Cushion <= 0) {
+ U = stripTag<Use::tagMaskN>(U->Next);
+ }
+ goto efficiency;
+ }
+ default:
+ --digits;
+ Acc = (Acc << 1) | (Tag & 1);
+ if (Cushion <= 0) {
+ U = stripTag<Use::tagMaskN>(U->Next);
+ }
+ continue;
+ }
+ break;
+ }
+ }
+ // fall through
+ default:
+ Next = Next->Next;
+ // __builtin_prefetch(Next);
+ --Cushion;
+ Tag = extractTag<Use::NextPtrTag, Use::tagMaskN>(Next);
+ Next = stripTag<Use::tagMaskN>(Next);
+ } // switch
+ } // while
+
+ // Now we know that we have a nice cushion between U and Next. Do the same
+ // thing as above, but don't decrement Cushion any more, instead push U
+ // forward. After the value is found, repaint beginning at U.
+
+ while (1) {
+ switch (Tag) {
+ case Use::fullStopTagN: {
+ punchAwayDigits(U->Prev);
+ repaintByCalculating(reinterpret_cast<unsigned long>(Next), U);
+ return reinterpret_cast<Value*>(Next);
+ }
+ case Use::stopTagN: {
+ // try to pick up exactly requiredSteps digits
+ int digits = requiredSteps;
+ Acc = 0;
+ Use *Tagspace(Next);
+
+ while (1) {
+ if (!digits) {
+ punchAwayDigits(U->Prev);
+ repaintByCopying(Tagspace, U);
+ return reinterpret_cast<Value*>(Acc << spareBits);
+ }
+
+ Next = Next->Next;
+ // __builtin_prefetch(Next);
+ U = stripTag<Use::tagMaskN>(U->Next);
+ Tag = extractTag<Use::NextPtrTag, Use::tagMaskN>(Next);
+ Next = stripTag<Use::tagMaskN>(Next);
+ switch (Tag) {
+ case Use::fullStopTagN: {
+ punchAwayDigits(U->Prev);
+ repaintByCalculating(reinterpret_cast<unsigned long>(Next), U);
+ return reinterpret_cast<Value*>(Next);
+ }
+ case Use::stopTagN: {
+ break;
+ }
+ default:
+ --digits;
+ Acc = (Acc << 1) | (Tag & 1);
+ continue;
+ }
+ break;
+ }
+ }
+ // fall through
+ default:
+ Next = Next->Next;
+ // __builtin_prefetch(Next);
+ U = stripTag<Use::tagMaskN>(U->Next);
+ Tag = extractTag<Use::NextPtrTag, Use::tagMaskN>(Next);
+ Next = stripTag<Use::tagMaskN>(Next);
+ } // switch
+ } // while
+}
+
+
+/// skipPotentiallyGathering is invoked for either
+/// - picking up exactly ToGo digits
+/// - or finding a stop which marks the beginning
+/// of a repaintable area
+///
+static inline Value *skipPotentiallyGathering(Use *U,
+ unsigned long Acc,
+ int ToGo) {
+ while (1) {
+ if (!ToGo)
+ return reinterpret_cast<Value*>(Acc << spareBits);
+
+ Use *Next(U->Next);
+ // __builtin_prefetch(Next);
+ Use::NextPtrTag Tag(extractTag<Use::NextPtrTag, Use::tagMaskN>(Next));
+ Next = stripTag<Use::tagMaskN>(Next);
+ switch (Tag) {
+ case Use::fullStopTagN:
+ return reinterpret_cast<Value*>(Next);
+ case Use::stopTagN:
+ return gatherAndPotentiallyRepaint(Next);
+ default:
+ Acc = (Acc << 1) | (Tag & 1);
+ --ToGo;
+ U = Next;
+ }
+ }
+}
+
+}; // class UseWaymark
+
+Value *Use::getValue() const {
+ // __builtin_prefetch(Next);
+ NextPtrTag Tag(extractTag<NextPtrTag, tagMaskN>(Next));
+ switch (Tag) {
+ case fullStopTagN:
+ return reinterpret_cast<Value*>(stripTag<tagMaskN>(Next));
+ case stopTagN:
+ return UseWaymark::gatherAndPotentiallyRepaint(Next);
+ default:
+ return UseWaymark::skipPotentiallyGathering(stripTag<tagMaskN>(Next),
+ Tag & 1,
+ Use::UseWaymark::requiredSteps - 1);
+ }
+}
+
+static char TagChar(int Tag) {
+ return "s10S"[Tag];
+}
+
+void Use::showWaymarks() const {
+ const Use *me(this);
+ if (NextPtrTag Tag = extractTag<Use::NextPtrTag, Use::tagMaskN>(me)) {
+ me = stripTag<tagMaskN>(me);
+ std::cerr << '(' << TagChar(Tag) << ')';
+ }
+
+ me = me->Next;
+ NextPtrTag TagHere = extractTag<Use::NextPtrTag, Use::tagMaskN>(me);
+ std::cerr << TagChar(TagHere);
+
+ me = stripTag<tagMaskN>(me);
+ if (TagHere == fullStopTagN) {
+ std::cerr << " ---> " << me << std::endl;
+ std::cerr << "1234567890123456789012345678901234567890123456789012345678901234567890" << std::endl;
+ std::cerr << " 1 2 3 4 5 6 7" << std::endl;
+ }
+ else
+ me->showWaymarks();
+}
+
+} // namespace llvm
+
+#if 0
+
+// ################################################################
+// ############################# TESTS ############################
+// ################################################################
+
+using namespace llvm;
+
+namespace T1
+{
+ Use u00;
+}
+
+namespace T2
+{
+ Use u00((Value*)0xCAFEBABCUL);
+ Use u01(u00);
+}
+
+namespace T3
+{
+ template <unsigned NEST>
+ struct UseChain;
+
+ template <>
+ struct UseChain<0> {
+ Use first;
+ UseChain(Value *V) : first(V) {}
+ UseChain(Use &U) : first(U) {}
+ };
+
+ template <unsigned NEST>
+ struct UseChain {
+ Use first;
+ UseChain<NEST - 1> rest;
+ UseChain(Value *V)
+ : first(rest.first)
+ , rest(V) {}
+ UseChain(Use &U)
+ : first(rest.first)
+ , rest(U) {}
+ };
+
+ UseChain<30> uc31((Value*)0xCAFEBABCUL);
+ Use& u31(uc31.first);
+ UseChain<31> uc32((Value*)0xCAFEBABCUL);
+ Use& u32(uc32.first);
+}
+
+namespace T4
+{
+ template <unsigned NEST, unsigned long PAT>
+ struct UseChain;
+
+ template <unsigned long PAT>
+ struct UseChain<0, PAT> {
+ Use first;
+ static const unsigned long Pat = PAT >> 2;
+ UseChain(Value *V) : first(V) {}
+ UseChain(Use &U) : first(U) {}
+ };
+
+ template <unsigned NEST, unsigned long PAT>
+ struct UseChain {
+ Use first;
+ UseChain<NEST - 1, PAT> rest;
+ static const unsigned long Digit = UseChain<NEST - 1, PAT>::Pat & 1;
+ static const Use::NextPtrTag Tag = Digit ? Use::oneDigitTagN : Use::zeroDigitTagN;
+ static const unsigned long Pat = UseChain<NEST - 1, PAT>::Pat >> 1;
+ UseChain(Value *V = reinterpret_cast<Value*>(PAT))
+ : first(*addTag(&rest.first, Tag))
+ , rest(V) {}
+ UseChain(Use &U)
+ : first(*addTag(&rest.first, Tag))
+ , rest(U) {}
+ };
+
+ UseChain<30, 0xCAFEBABCUL> uc31;
+ Use& u31(uc31.first);
+ Use us32(u31);
+
+ UseChain<29, 0xCAFEBABCUL> uc30;
+ Use& u30(uc30.first);
+ Use us31(u30);
+
+ T3::UseChain<3> s3a((Value*)0xCAFEBABCUL);
+ UseChain<30, 0xCAFEBABCUL> uc31s3S(s3a.first);
+ Use& m35(uc31s3S.first);
+
+ T3::UseChain<3> s3b((Value*)0xCAFEBABCUL);
+ UseChain<29, 0xCAFEBABCUL> uc30s3S(s3b.first);
+ Use& m34(uc30s3S.first);
+
+ T3::UseChain<3> s3c((Value*)0xCAFEBABCUL);
+ UseChain<25, 0xCAFEBABCUL> uc25s3S(s3c.first);
+ Use& m30(uc25s3S.first);
+
+ Use ms36(m35);
+ Use ms35(m34);
+ Use ms31(m30);
+ Use ms32(ms31);
+
+ UseChain<24, 0xCAFEBABCUL> uc25;
+ Use& u25(uc25.first);
+ T3::UseChain<10> m11s24dS(u25);
+ Use& m36(m11s24dS.first);
+
+
+ T3::UseChain<10> s10S((Value*)0xCAFEBABCUL);
+ UseChain<20, 0xCAFEBABCUL> d20ss10S(s10S.first);
+ T3::UseChain<20> s20sd20ss10S(d20ss10S.first);
+ Use& m53(s20sd20ss10S.first);
+}
+
+
+int main(){
+ if (NULL != T1::u00.getValue())
+ return 1;
+ if ((Value*)0xCAFEBABCUL != T2::u00.getValue())
+ return 2;
+ if ((Value*)0xCAFEBABCUL != T2::u01.getValue())
+ return 2;
+ if ((Value*)0xCAFEBABCUL != T3::u31.getValue())
+ return 3;
+ if ((Value*)0xCAFEBABCUL != T3::u32.getValue())
+ return 3;
+ if ((Value*)0xCAFEBABCUL != T3::u32.getValue()) // check the mutated value
+ return 3;
+ if ((Value*)0xCAFEBABCUL != T4::u31.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::u30.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::us32.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::us31.getValue())
+ return 4;
+
+ // mixed tests
+ if ((Value*)0xCAFEBABCUL != T4::m35.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::m34.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::m30.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::ms36.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::ms35.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::ms35.getValue()) // check the mutated value
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::ms32.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::ms32.getValue())
+ return 4;
+ if ((Value*)0xCAFEBABCUL != T4::ms32.getValue()) // check the mutated value
+ return 4;
+
+ T4::m36.showWaymarks();
+ if ((Value*)0xCAFEBABCUL != T4::m36.getValue())
+ return 4;
+ T4::m36.showWaymarks();
+ if ((Value*)0xCAFEBABCUL != T4::m36.getValue()) // check the mutated value
+ return 4;
+ T4::m36.showWaymarks();
+
+ T4::m53.showWaymarks();
+ if ((Value*)0xCAFEBABCUL != T4::m53.getValue())
+ return 4;
+ T4::m53.showWaymarks();
+ if ((Value*)0xCAFEBABCUL != T4::m53.getValue()) // check the mutated value
+ return 4;
+ T4::m53.showWaymarks();
+}
+
+#endif
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-12 22:23:35 +0000