| Methods Summary |
|---|
| public void | add(DalvInsn insn)Adds an instruction to the output.
insns.add(insn);
updateInfo(insn);
|
| private static void | addConstants(java.util.HashSet result, DalvInsn insn)Helper for {@link #getAllConstants} which adds all the info for
a single instruction.
if (insn instanceof CstInsn) {
Constant cst = ((CstInsn) insn).getConstant();
result.add(cst);
} else if (insn instanceof LocalSnapshot) {
RegisterSpecSet specs = ((LocalSnapshot) insn).getLocals();
int size = specs.size();
for (int i = 0; i < size; i++) {
addConstants(result, specs.get(i));
}
} else if (insn instanceof LocalStart) {
RegisterSpec spec = ((LocalStart) insn).getLocal();
addConstants(result, spec);
}
|
| private static void | addConstants(java.util.HashSet result, com.android.dexgen.rop.code.RegisterSpec spec)Helper for {@link #getAllConstants} which adds all the info for
a single {@code RegisterSpec}.
if (spec == null) {
return;
}
LocalItem local = spec.getLocalItem();
CstUtf8 name = local.getName();
CstUtf8 signature = local.getSignature();
Type type = spec.getType();
if (type != Type.KNOWN_NULL) {
result.add(CstType.intern(type));
}
if (name != null) {
result.add(name);
}
if (signature != null) {
result.add(signature);
}
|
| private void | assignAddresses()Helper for {@link #assignAddressesAndFixBranches}, which
assigns an address to each instruction, in order.
int address = 0;
int size = insns.size();
for (int i = 0; i < size; i++) {
DalvInsn insn = insns.get(i);
insn.setAddress(address);
address += insn.codeSize();
}
|
| private void | assignAddressesAndFixBranches()Helper for {@link #finishProcessingAndGetList}, which assigns
addresses to each instruction, possibly rewriting branches to
fix ones that wouldn't otherwise be able to reach their
targets.
for (;;) {
assignAddresses();
if (!fixBranches()) {
break;
}
}
|
| public void | assignIndices(DalvCode.AssignIndicesCallback callback)Assigns indices in all instructions that need them, using the
given callback to perform lookups. This should be called before
calling {@link #finishProcessingAndGetList}.
for (DalvInsn insn : insns) {
if (insn instanceof CstInsn) {
assignIndices((CstInsn) insn, callback);
}
}
|
| private static void | assignIndices(CstInsn insn, DalvCode.AssignIndicesCallback callback)Helper for {@link #assignIndices} which does assignment for one
instruction.
Constant cst = insn.getConstant();
int index = callback.getIndex(cst);
if (index >= 0) {
insn.setIndex(index);
}
if (cst instanceof CstMemberRef) {
CstMemberRef member = (CstMemberRef) cst;
CstType definer = member.getDefiningClass();
index = callback.getIndex(definer);
if (index >= 0) {
insn.setClassIndex(index);
}
}
|
| private int | calculateReservedCount(InsnFormat[] formats)Helper for {@link #reserveRegisters}, which does one
pass over the instructions, calculating the number of
registers that need to be reserved. It also updates the
{@code formats} list to help avoid extra work in future
register reservation passes.
int size = insns.size();
/*
* Potential new value of reservedCount, which gets updated in the
* following loop. It starts out with the existing reservedCount
* and gets increased if it turns out that additional registers
* need to be reserved.
*/
int newReservedCount = reservedCount;
for (int i = 0; i < size; i++) {
DalvInsn insn = insns.get(i);
InsnFormat originalFormat = formats[i];
InsnFormat newFormat = findFormatForInsn(insn, originalFormat);
if (originalFormat == newFormat) {
continue;
}
if (newFormat == null) {
/*
* The instruction will need to be expanded, so reserve
* registers for it.
*/
int reserve = insn.getMinimumRegisterRequirement();
if (reserve > newReservedCount) {
newReservedCount = reserve;
}
}
formats[i] = newFormat;
}
return newReservedCount;
|
| private InsnFormat | findFormatForInsn(DalvInsn insn, InsnFormat format)Attempts to fit the given instruction into a format, returning
either a format that the instruction fits into or {@code null}
to indicate that the instruction will need to be expanded. This
fitting process starts with the given format as a first "best
guess" and then pessimizes from there if necessary.
if (format == null) {
// The instruction is already known not to fit any simple format.
return format;
}
if (format.isCompatible(insn)) {
// The instruction already fits in the current best-known format.
return format;
}
Dop dop = insn.getOpcode();
int family = dop.getFamily();
for (;;) {
format = format.nextUp();
if ((format == null) ||
(format.isCompatible(insn) &&
(Dops.getOrNull(family, format) != null))) {
break;
}
}
return format;
|
| public DalvInsnList | finishProcessingAndGetList()Does final processing on this instance and gets the output as
a {@link DalvInsnList}. Final processing consists of:
- optionally renumbering registers (to make room as needed for
expanded instructions)
- picking a final opcode for each instruction
- rewriting instructions, because of register number,
constant pool index, or branch target size issues
- assigning final addresses
Note: This method may only be called once per instance
of this class.
if (reservedCount >= 0) {
throw new UnsupportedOperationException("already processed");
}
InsnFormat[] formats = makeFormatsArray();
reserveRegisters(formats);
massageInstructions(formats);
assignAddressesAndFixBranches();
return DalvInsnList.makeImmutable(insns,
reservedCount + unreservedRegCount);
|
| private boolean | fixBranches()Helper for {@link #assignAddressesAndFixBranches}, which checks
the branch target size requirement of each branch instruction
to make sure it fits. For instructions that don't fit, this
rewrites them to use a {@code goto} of some sort. In the
case of a conditional branch that doesn't fit, the sense of the
test is reversed in order to branch around a {@code goto}
to the original target.
int size = insns.size();
boolean anyFixed = false;
for (int i = 0; i < size; i++) {
DalvInsn insn = insns.get(i);
if (!(insn instanceof TargetInsn)) {
// This loop only needs to inspect TargetInsns.
continue;
}
Dop dop = insn.getOpcode();
InsnFormat format = dop.getFormat();
TargetInsn target = (TargetInsn) insn;
if (format.branchFits(target)) {
continue;
}
if (dop.getFamily() == DalvOps.GOTO) {
// It is a goto; widen it if possible.
InsnFormat newFormat = findFormatForInsn(insn, format);
if (newFormat == null) {
/*
* The branch is already maximally large. This should
* only be possible if a method somehow manages to have
* more than 2^31 code units.
*/
throw new UnsupportedOperationException("method too long");
}
dop = Dops.getOrNull(dop.getFamily(), newFormat);
insn = insn.withOpcode(dop);
insns.set(i, insn);
} else {
/*
* It is a conditional: Reverse its sense, and arrange for
* it to branch around an absolute goto to the original
* branch target.
*
* Note: An invariant of the list being processed is
* that every TargetInsn is followed by a CodeAddress.
* Hence, it is always safe to get the next element
* after a TargetInsn and cast it to CodeAddress, as
* is happening a few lines down.
*
* Also note: Size gets incremented by one here, as we
* have -- in the net -- added one additional element
* to the list, so we increment i to match. The added
* and changed elements will be inspected by a repeat
* call to this method after this invocation returns.
*/
CodeAddress newTarget;
try {
newTarget = (CodeAddress) insns.get(i + 1);
} catch (IndexOutOfBoundsException ex) {
// The TargetInsn / CodeAddress invariant was violated.
throw new IllegalStateException(
"unpaired TargetInsn (dangling)");
} catch (ClassCastException ex) {
// The TargetInsn / CodeAddress invariant was violated.
throw new IllegalStateException("unpaired TargetInsn");
}
TargetInsn gotoInsn =
new TargetInsn(Dops.GOTO, target.getPosition(),
RegisterSpecList.EMPTY, target.getTarget());
insns.set(i, gotoInsn);
insns.add(i, target.withNewTargetAndReversed(newTarget));
size++;
i++;
}
anyFixed = true;
}
return anyFixed;
|
| public java.util.HashSet | getAllConstants()Returns the set of all constants referred to by instructions added
to this instance.
HashSet<Constant> result = new HashSet<Constant>(20);
for (DalvInsn insn : insns) {
addConstants(result, insn);
}
return result;
|
| public boolean | hasAnyLocalInfo()Returns whether this instance has any local variable information.
return hasAnyLocalInfo;
|
| public boolean | hasAnyPositionInfo()Returns whether any of the instructions added to this instance
come with position info.
return hasAnyPositionInfo;
|
| private static boolean | hasLocalInfo(DalvInsn insn)Helper for {@link #add} which scrutinizes a single
instruction for local variable information.
if (insn instanceof LocalSnapshot) {
RegisterSpecSet specs = ((LocalSnapshot) insn).getLocals();
int size = specs.size();
for (int i = 0; i < size; i++) {
if (hasLocalInfo(specs.get(i))) {
return true;
}
}
} else if (insn instanceof LocalStart) {
RegisterSpec spec = ((LocalStart) insn).getLocal();
if (hasLocalInfo(spec)) {
return true;
}
}
return false;
|
| private static boolean | hasLocalInfo(com.android.dexgen.rop.code.RegisterSpec spec)Helper for {@link #hasAnyLocalInfo} which scrutinizes a single
register spec.
return (spec != null)
&& (spec.getLocalItem().getName() != null);
|
| public void | insert(int at, DalvInsn insn)Inserts an instruction in the output at the given offset.
insns.add(at, insn);
updateInfo(insn);
|
| private InsnFormat[] | makeFormatsArray()Helper for {@link #finishProcessingAndGetList}, which extracts
the format out of each instruction into a separate array, to be
further manipulated as things progress.
int size = insns.size();
InsnFormat[] result = new InsnFormat[size];
for (int i = 0; i < size; i++) {
result[i] = insns.get(i).getOpcode().getFormat();
}
return result;
|
| private void | massageInstructions(InsnFormat[] formats)Helper for {@link #finishProcessingAndGetList}, which goes
through each instruction in the output, making sure its opcode
can accomodate its arguments. In cases where the opcode is
unable to do so, this replaces the instruction with a larger
instruction with identical semantics that will work.
This method may also reserve a number of low-numbered
registers, renumbering the instructions' original registers, in
order to have register space available in which to move
very-high registers when expanding instructions into
multi-instruction sequences. This expansion is done when no
simple instruction format can be found for a given instruction that
is able to accomodate that instruction's registers.
This method ignores issues of branch target size, since
final addresses aren't known at the point that this method is
called.
if (reservedCount == 0) {
/*
* The easy common case: No registers were reserved, so we
* merely need to replace any instructions whose format changed
* during the reservation pass, but all instructions will stay
* at their original indices, and the instruction list doesn't
* grow.
*/
int size = insns.size();
for (int i = 0; i < size; i++) {
DalvInsn insn = insns.get(i);
Dop dop = insn.getOpcode();
InsnFormat format = formats[i];
if (format != dop.getFormat()) {
dop = Dops.getOrNull(dop.getFamily(), format);
insns.set(i, insn.withOpcode(dop));
}
}
} else {
/*
* The difficult uncommon case: Some instructions have to be
* expanded to deal with high registers.
*/
insns = performExpansion(formats);
}
|
| private java.util.ArrayList | performExpansion(InsnFormat[] formats)Helper for {@link #massageInstructions}, which constructs a
replacement list, where each {link DalvInsn} instance that
couldn't be represented simply (due to register representation
problems) is expanded into a series of instances that together
perform the proper function.
int size = insns.size();
ArrayList<DalvInsn> result = new ArrayList<DalvInsn>(size * 2);
for (int i = 0; i < size; i++) {
DalvInsn insn = insns.get(i);
Dop dop = insn.getOpcode();
InsnFormat originalFormat = dop.getFormat();
InsnFormat currentFormat = formats[i];
DalvInsn prefix;
DalvInsn suffix;
if (currentFormat != null) {
// No expansion is necessary.
prefix = null;
suffix = null;
} else {
// Expansion is required.
prefix = insn.hrPrefix();
suffix = insn.hrSuffix();
/*
* Get the initial guess as to the hr version, but then
* let findFormatForInsn() pick a better format, if any.
*/
insn = insn.hrVersion();
originalFormat = insn.getOpcode().getFormat();
currentFormat = findFormatForInsn(insn, originalFormat);
}
if (prefix != null) {
result.add(prefix);
}
if (currentFormat != originalFormat) {
dop = Dops.getOrNull(dop.getFamily(), currentFormat);
insn = insn.withOpcode(dop);
}
result.add(insn);
if (suffix != null) {
result.add(suffix);
}
}
return result;
|
| private void | reserveRegisters(InsnFormat[] formats)Helper for {@link #finishProcessingAndGetList}, which figures
out how many reserved registers are required and then reserving
them. It also updates the given {@code formats} array so
as to avoid extra work when constructing the massaged
instruction list.
int oldReservedCount = (reservedCount < 0) ? 0 : reservedCount;
/*
* Call calculateReservedCount() and then perform register
* reservation, repeatedly until no new reservations happen.
*/
for (;;) {
int newReservedCount = calculateReservedCount(formats);
if (oldReservedCount >= newReservedCount) {
break;
}
int reservedDifference = newReservedCount - oldReservedCount;
int size = insns.size();
for (int i = 0; i < size; i++) {
/*
* CodeAddress instance identity is used to link
* TargetInsns to their targets, so it is
* inappropriate to make replacements, and they don't
* have registers in any case. Hence, the instanceof
* test below.
*/
DalvInsn insn = insns.get(i);
if (!(insn instanceof CodeAddress)) {
/*
* No need to call this.set() since the format and
* other info are the same.
*/
insns.set(i, insn.withRegisterOffset(reservedDifference));
}
}
oldReservedCount = newReservedCount;
}
reservedCount = oldReservedCount;
|
| public void | reverseBranch(int which, CodeAddress newTarget)Reverses a branch which is buried a given number of instructions
backward in the output. It is illegal to call this unless the
indicated instruction really is a reversible branch.
int size = insns.size();
int index = size - which - 1;
TargetInsn targetInsn;
try {
targetInsn = (TargetInsn) insns.get(index);
} catch (IndexOutOfBoundsException ex) {
// Translate the exception.
throw new IllegalArgumentException("too few instructions");
} catch (ClassCastException ex) {
// Translate the exception.
throw new IllegalArgumentException("non-reversible instruction");
}
/*
* No need to call this.set(), since the format and other info
* are the same.
*/
insns.set(index, targetInsn.withNewTargetAndReversed(newTarget));
|
| private void | updateInfo(DalvInsn insn)Helper for {@link #add} and {@link #insert},
which updates the position and local info flags.
if (! hasAnyPositionInfo) {
SourcePosition pos = insn.getPosition();
if (pos.getLine() >= 0) {
hasAnyPositionInfo = true;
}
}
if (! hasAnyLocalInfo) {
if (hasLocalInfo(insn)) {
hasAnyLocalInfo = true;
}
}
|
