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Unified Diff: src/arm/assembler-arm-inl.h

Issue 496443003: Add ARMv6 support for the out-of-line constant pool. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: kImmed8 Created 6 years, 4 months ago
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Index: src/arm/assembler-arm-inl.h
diff --git a/src/arm/assembler-arm-inl.h b/src/arm/assembler-arm-inl.h
index 1cfe34b241fc1ab804032d2babe2126afec9eab2..8b5c4b8c5634b4bf33d2f010f46e82ae9063246d 100644
--- a/src/arm/assembler-arm-inl.h
+++ b/src/arm/assembler-arm-inl.h
@@ -423,36 +423,58 @@ void Assembler::emit(Instr x) {
Address Assembler::target_address_from_return_address(Address pc) {
// Returns the address of the call target from the return address that will
// be returned to after a call.
- // Call sequence on V7 or later is :
+ // Call sequence on V7 or later is:
// movw ip, #... @ call address low 16
// movt ip, #... @ call address high 16
// blx ip
// @ return address
- // Or pre-V7 or cases that need frequent patching, the address is in the
+ // For V6 when the constant pool is unavailable, it is:
+ // mov ip, #... @ call address low 8
+ // orr ip, ip, #... @ call address 2nd 8
+ // orr ip, ip, #... @ call address 3rd 8
+ // orr ip, ip, #... @ call address high 8
+ // blx ip
+ // @ return address
+ // In cases that need frequent patching, the address is in the
// constant pool. It could be a small constant pool load:
// ldr ip, [pc / pp, #...] @ call address
// blx ip
// @ return address
- // Or an extended constant pool load:
+ // Or an extended constant pool load (ARMv7):
// movw ip, #...
// movt ip, #...
// ldr ip, [pc, ip] @ call address
// blx ip
// @ return address
+ // Or an extended constant pool load (ARMv6):
+ // mov ip, #...
+ // orr ip, ip, #...
+ // orr ip, ip, #...
+ // orr ip, ip, #...
+ // ldr ip, [pc, ip] @ call address
+ // blx ip
+ // @ return address
Address candidate = pc - 2 * Assembler::kInstrSize;
Instr candidate_instr(Memory::int32_at(candidate));
if (IsLdrPcImmediateOffset(candidate_instr) |
IsLdrPpImmediateOffset(candidate_instr)) {
return candidate;
- } else if (IsLdrPpRegOffset(candidate_instr)) {
- candidate = pc - 4 * Assembler::kInstrSize;
- DCHECK(IsMovW(Memory::int32_at(candidate)) &&
- IsMovT(Memory::int32_at(candidate + Assembler::kInstrSize)));
- return candidate;
} else {
- candidate = pc - 3 * Assembler::kInstrSize;
- DCHECK(IsMovW(Memory::int32_at(candidate)) &&
- IsMovT(Memory::int32_at(candidate + kInstrSize)));
+ if (IsLdrPpRegOffset(candidate_instr)) {
+ candidate -= Assembler::kInstrSize;
+ }
+ if (CpuFeatures::IsSupported(ARMv7)) {
+ candidate -= 1 * Assembler::kInstrSize;
+ DCHECK(IsMovW(Memory::int32_at(candidate)) &&
+ IsMovT(Memory::int32_at(candidate + Assembler::kInstrSize)));
+ } else {
+ candidate -= 3 * Assembler::kInstrSize;
+ DCHECK(
+ IsMovImmed(Memory::int32_at(candidate)) &&
+ IsOrrImmed(Memory::int32_at(candidate + Assembler::kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(candidate + 2 * Assembler::kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(candidate + 3 * Assembler::kInstrSize)));
+ }
return candidate;
}
}
@@ -469,14 +491,28 @@ Address Assembler::return_address_from_call_start(Address pc) {
// Load from constant pool, small section.
return pc + kInstrSize * 2;
} else {
- DCHECK(IsMovW(Memory::int32_at(pc)));
- DCHECK(IsMovT(Memory::int32_at(pc + kInstrSize)));
- if (IsLdrPpRegOffset(Memory::int32_at(pc + kInstrSize))) {
- // Load from constant pool, extended section.
- return pc + kInstrSize * 4;
+ if (CpuFeatures::IsSupported(ARMv7)) {
+ DCHECK(IsMovW(Memory::int32_at(pc)));
+ DCHECK(IsMovT(Memory::int32_at(pc + kInstrSize)));
+ if (IsLdrPpRegOffset(Memory::int32_at(pc + 2 * kInstrSize))) {
+ // Load from constant pool, extended section.
+ return pc + kInstrSize * 4;
+ } else {
+ // A movw / movt load immediate.
+ return pc + kInstrSize * 3;
+ }
} else {
- // A movw / movt load immediate.
- return pc + kInstrSize * 3;
+ DCHECK(IsMovImmed(Memory::int32_at(pc)));
+ DCHECK(IsOrrImmed(Memory::int32_at(pc + kInstrSize)));
+ DCHECK(IsOrrImmed(Memory::int32_at(pc + 2 * kInstrSize)));
+ DCHECK(IsOrrImmed(Memory::int32_at(pc + 3 * kInstrSize)));
+ if (IsLdrPpRegOffset(Memory::int32_at(pc + 4 * kInstrSize))) {
+ // Load from constant pool, extended section.
+ return pc + kInstrSize * 6;
+ } else {
+ // A mov / orr load immediate.
+ return pc + kInstrSize * 5;
+ }
}
}
}
@@ -493,10 +529,17 @@ void Assembler::deserialization_set_special_target_at(
bool Assembler::is_constant_pool_load(Address pc) {
- return !Assembler::IsMovW(Memory::int32_at(pc)) ||
- (FLAG_enable_ool_constant_pool &&
- Assembler::IsLdrPpRegOffset(
- Memory::int32_at(pc + 2 * Assembler::kInstrSize)));
+ if (CpuFeatures::IsSupported(ARMv7)) {
+ return !Assembler::IsMovW(Memory::int32_at(pc)) ||
+ (FLAG_enable_ool_constant_pool &&
+ Assembler::IsLdrPpRegOffset(
+ Memory::int32_at(pc + 2 * Assembler::kInstrSize)));
+ } else {
+ return !Assembler::IsMovImmed(Memory::int32_at(pc)) ||
+ (FLAG_enable_ool_constant_pool &&
+ Assembler::IsLdrPpRegOffset(
+ Memory::int32_at(pc + 4 * Assembler::kInstrSize)));
+ }
}
@@ -505,10 +548,22 @@ Address Assembler::constant_pool_entry_address(
if (FLAG_enable_ool_constant_pool) {
DCHECK(constant_pool != NULL);
int cp_offset;
- if (IsMovW(Memory::int32_at(pc))) {
+ if (!CpuFeatures::IsSupported(ARMv7) && IsMovImmed(Memory::int32_at(pc))) {
+ DCHECK(IsOrrImmed(Memory::int32_at(pc + kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(pc + 2 * kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(pc + 3 * kInstrSize)) &&
+ IsLdrPpRegOffset(Memory::int32_at(pc + 4 * kInstrSize)));
+ // This is an extended constant pool lookup (ARMv6).
+ Instr mov_instr = instr_at(pc);
+ Instr orr_instr_1 = instr_at(pc + kInstrSize);
+ Instr orr_instr_2 = instr_at(pc + 2 * kInstrSize);
+ Instr orr_instr_3 = instr_at(pc + 3 * kInstrSize);
+ cp_offset = DecodeShiftImm(mov_instr) | DecodeShiftImm(orr_instr_1) |
+ DecodeShiftImm(orr_instr_2) | DecodeShiftImm(orr_instr_3);
+ } else if (IsMovW(Memory::int32_at(pc))) {
DCHECK(IsMovT(Memory::int32_at(pc + kInstrSize)) &&
IsLdrPpRegOffset(Memory::int32_at(pc + 2 * kInstrSize)));
- // This is an extended constant pool lookup.
+ // This is an extended constant pool lookup (ARMv7).
Instruction* movw_instr = Instruction::At(pc);
Instruction* movt_instr = Instruction::At(pc + kInstrSize);
cp_offset = (movt_instr->ImmedMovwMovtValue() << 16) |
@@ -532,8 +587,8 @@ Address Assembler::target_address_at(Address pc,
if (is_constant_pool_load(pc)) {
// This is a constant pool lookup. Return the value in the constant pool.
return Memory::Address_at(constant_pool_entry_address(pc, constant_pool));
- } else {
- // This is an movw_movt immediate load. Return the immediate.
+ } else if (CpuFeatures::IsSupported(ARMv7)) {
+ // This is an movw / movt immediate load. Return the immediate.
DCHECK(IsMovW(Memory::int32_at(pc)) &&
IsMovT(Memory::int32_at(pc + kInstrSize)));
Instruction* movw_instr = Instruction::At(pc);
@@ -541,6 +596,20 @@ Address Assembler::target_address_at(Address pc,
return reinterpret_cast<Address>(
(movt_instr->ImmedMovwMovtValue() << 16) |
movw_instr->ImmedMovwMovtValue());
+ } else {
+ // This is an mov / orr immediate load. Return the immediate.
+ DCHECK(IsMovImmed(Memory::int32_at(pc)) &&
+ IsOrrImmed(Memory::int32_at(pc + kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(pc + 2 * kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(pc + 3 * kInstrSize)));
+ Instr mov_instr = instr_at(pc);
+ Instr orr_instr_1 = instr_at(pc + kInstrSize);
+ Instr orr_instr_2 = instr_at(pc + 2 * kInstrSize);
+ Instr orr_instr_3 = instr_at(pc + 3 * kInstrSize);
+ Address ret = reinterpret_cast<Address>(
+ DecodeShiftImm(mov_instr) | DecodeShiftImm(orr_instr_1) |
+ DecodeShiftImm(orr_instr_2) | DecodeShiftImm(orr_instr_3));
+ return ret;
}
}
@@ -560,9 +629,9 @@ void Assembler::set_target_address_at(Address pc,
// ldr ip, [pp, #...]
// since the instruction accessing this address in the constant pool remains
// unchanged.
- } else {
- // This is an movw_movt immediate load. Patch the immediate embedded in the
- // instructions.
+ } else if (CpuFeatures::IsSupported(ARMv7)) {
+ // This is an movw / movt immediate load. Patch the immediate embedded in
+ // the instructions.
DCHECK(IsMovW(Memory::int32_at(pc)));
DCHECK(IsMovT(Memory::int32_at(pc + kInstrSize)));
uint32_t* instr_ptr = reinterpret_cast<uint32_t*>(pc);
@@ -574,6 +643,26 @@ void Assembler::set_target_address_at(Address pc,
if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
CpuFeatures::FlushICache(pc, 2 * kInstrSize);
}
+ } else {
+ // This is an mov / orr immediate load. Patch the immediate embedded in
+ // the instructions.
+ DCHECK(IsMovImmed(Memory::int32_at(pc)) &&
+ IsOrrImmed(Memory::int32_at(pc + kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(pc + 2 * kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(pc + 3 * kInstrSize)));
+ uint32_t* instr_ptr = reinterpret_cast<uint32_t*>(pc);
+ uint32_t immediate = reinterpret_cast<uint32_t>(target);
+ instr_ptr[0] = PatchShiftImm(instr_ptr[0], immediate & kImm8Mask);
+ instr_ptr[1] = PatchShiftImm(instr_ptr[1], immediate & (kImm8Mask << 8));
+ instr_ptr[2] = PatchShiftImm(instr_ptr[2], immediate & (kImm8Mask << 16));
+ instr_ptr[3] = PatchShiftImm(instr_ptr[3], immediate & (kImm8Mask << 24));
+ DCHECK(IsMovImmed(Memory::int32_at(pc)) &&
+ IsOrrImmed(Memory::int32_at(pc + kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(pc + 2 * kInstrSize)) &&
+ IsOrrImmed(Memory::int32_at(pc + 3 * kInstrSize)));
+ if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
+ CpuFeatures::FlushICache(pc, 4 * kInstrSize);
+ }
}
}
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