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Unified Diff: runtime/vm/assembler_arm.cc

Issue 12224024: Generate first ARM assembler test and execute (simulate) it. (Closed) Base URL: http://dart.googlecode.com/svn/branches/bleeding_edge/dart/
Patch Set: Created 7 years, 10 months ago
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Index: runtime/vm/assembler_arm.cc
===================================================================
--- runtime/vm/assembler_arm.cc (revision 18162)
+++ runtime/vm/assembler_arm.cc (working copy)
@@ -72,7 +72,7 @@
const uint32_t offset_mask = (1 << 12) - 1;
uint32_t offset = encoding_ & offset_mask;
ASSERT(offset < (1 << 10)); // In the range 0 to +1020.
- ASSERT(Utils::Utils::IsAligned(offset, 2)); // Multiple of 4.
+ ASSERT(Utils::IsAligned(offset, 4)); // Multiple of 4.
int mode = encoding_ & ((8|4|1) << 21);
ASSERT((mode == Offset) || (mode == NegOffset));
uint32_t vencoding = (encoding_ & (0xf << kRnShift)) | (offset >> 2);
@@ -83,6 +83,17 @@
}
+void Assembler::InitializeMemoryWithBreakpoints(uword data, int length) {
+ ASSERT(Utils::IsAligned(data, 4));
+ ASSERT(Utils::IsAligned(length, 4));
+ const uword end = data + length;
+ while (data < end) {
+ *reinterpret_cast<int32_t*>(data) = Instr::kBreakPointInstruction;
+ data += 4;
+ }
+}
+
+
void Assembler::Emit(int32_t value) {
AssemblerBuffer::EnsureCapacity ensured(&buffer_);
buffer_.Emit<int32_t>(value);
@@ -1020,7 +1031,18 @@
void Assembler::LoadObject(Register rd, const Object& object) {
- UNIMPLEMENTED();
+ // TODO(regis): If the object is never relocated (null, true, false, ...),
+ // load as immediate.
+ int32_t offset = AddObject(object);
+ ASSERT(Utils::IsAligned(offset, 4) && (offset >= 0));
+ if (Address::CanHoldLoadOffset(kLoadWord, offset)) {
+ ldr(rd, Address(CP, offset));
+ } else {
+ int32_t offset12_hi = offset & ~kOffset12Mask; // signed
+ uint32_t offset12_lo = offset & kOffset12Mask; // unsigned
+ AddConstant(rd, CP, offset12_hi);
+ ldr(rd, Address(rd, offset12_lo));
+ }
}
@@ -1139,22 +1161,28 @@
void Assembler::Branch(const ExternalLabel* label) {
- // TODO(regis): Revisit this code sequence.
LoadImmediate(IP, label->address()); // Target address is never patched.
mov(PC, ShifterOperand(IP));
}
void Assembler::BranchLink(const ExternalLabel* label) {
- // TODO(regis): Revisit this code sequence.
- // Make sure that CodePatcher is able to patch this code sequence.
+ // TODO(regis): Make sure that CodePatcher is able to patch the label referred
+ // to by this code sequence.
// For added code robustness, use 'blx lr' in a patchable sequence and
// use 'blx ip' in a non-patchable sequence (see other BranchLink flavors).
- ldr(LR, Address(PC));
- Label skip;
- b(&skip);
- Emit(label->address()); // May get patched.
- Bind(&skip);
+ int32_t offset = AddExternalLabel(label);
+ ASSERT(Utils::IsAligned(offset, 4) && (offset >= 0));
+ if (Address::CanHoldLoadOffset(kLoadWord, offset)) {
+ ldr(LR, Address(CP, offset));
+ } else {
+ int32_t offset12_hi = offset & ~kOffset12Mask; // signed
+ uint32_t offset12_lo = offset & kOffset12Mask; // unsigned
+ // TODO(regis): Using AddConstant may generate too many sequences to be
+ // easily decoded by CodePatcher. If so, use a simpler fixed sequence.
+ AddConstant(LR, CP, offset12_hi);
Ivan Posva 2013/02/06 23:33:50 As discussed, please do not use macros here as the
regis 2013/02/07 00:53:24 Done.
+ ldr(LR, Address(LR, offset12_lo));
+ }
blx(LR); // Use blx instruction so that the return branch prediction works.
}
@@ -1494,6 +1522,32 @@
return ((((inst & kBranchOffsetMask) << 8) >> 6) + 8);
}
+
+int32_t Assembler::AddObject(const Object& obj) {
+ for (int i = 0; i < objects_.Length(); i++) {
Ivan Posva 2013/02/06 23:33:50 As discussed we should just return the offset here
regis 2013/02/07 00:53:24 Done.
+ if (objects_.At(i) == obj.raw()) {
+ // TODO(regis): Skip over header.
+ return /*kCodeObjectsHeaderSize +*/ 4*i;
+ }
+ }
+ objects_.Add(obj);
+ // TODO(regis): Skip over header.
+ return /*kCodeObjectsHeaderSize +*/ 4*(objects_.Length() - 1);
+}
+
+
+int32_t Assembler::AddExternalLabel(const ExternalLabel* label) {
+ const uword address = label->address();
+ ASSERT(Utils::IsAligned(address, 4));
+ // The address is stored in the object array as a RawSmi.
+ const Smi& smi = Smi::Handle(Smi::New(address >> kSmiTagShift));
+ // Do not reuse an existing entry, since each reference may be patched
+ // independently.
+ objects_.Add(smi);
+ // TODO(regis): Skip over header.
+ return /*kCodeObjectsHeaderSize +*/ 4*(objects_.Length() - 1);
Ivan Posva 2013/02/06 23:33:50 ditto.
regis 2013/02/07 00:53:24 Done.
+}
+
} // namespace dart
#endif // defined TARGET_ARCH_ARM

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