Revision: 6759
Author: [email protected]
Date: Sun Feb 13 05:49:57 2011
Log: ARM: Implement PatchStackCheckCodeAt and RevertStackCheckCode.
This patch also adds platform independent CPU instruction cache flushing.
BUG=none
TEST=none
Review URL: http://codereview.chromium.org/6410029
http://code.google.com/p/v8/source/detail?r=6759
Modified:
/branches/bleeding_edge/src/arm/deoptimizer-arm.cc
=======================================
--- /branches/bleeding_edge/src/arm/deoptimizer-arm.cc Sun Feb 13 02:24:39
2011
+++ /branches/bleeding_edge/src/arm/deoptimizer-arm.cc Sun Feb 13 05:49:57
2011
@@ -124,14 +124,62 @@
void Deoptimizer::PatchStackCheckCodeAt(Address pc_after,
Code* check_code,
Code* replacement_code) {
- UNIMPLEMENTED();
+ const int kInstrSize = Assembler::kInstrSize;
+ // The call of the stack guard check has the following form:
+ // e1 5d 00 0c cmp sp, <limit>
+ // 2a 00 00 01 bcs ok
+ // e5 9f c? ?? ldr ip, [pc, <stack guard address>]
+ // e1 2f ff 3c blx ip
+ ASSERT(Memory::int32_at(pc_after - kInstrSize) ==
+ (al | B24 | B21 | 15*B16 | 15*B12 | 15*B8 | BLX | ip.code()));
+ ASSERT(Assembler::IsLdrPcImmediateOffset(
+ Assembler::instr_at(pc_after - 2 * kInstrSize)));
+
+ // We patch the code to the following form:
+ // e1 5d 00 0c cmp sp, <limit>
+ // e1 a0 00 00 mov r0, r0 (NOP)
+ // e5 9f c? ?? ldr ip, [pc, <on-stack replacement address>]
+ // e1 2f ff 3c blx ip
+ // and overwrite the constant containing the
+ // address of the stack check stub.
+
+ // Replace conditional jump with NOP.
+ CodePatcher patcher(pc_after - 3 * kInstrSize, 1);
+ patcher.masm()->nop();
+
+ // Replace the stack check address in the constant pool
+ // with the entry address of the replacement code.
+ uint32_t stack_check_address_offset = Memory::uint16_at(pc_after -
+ 2 * kInstrSize) & 0xfff;
+ Address stack_check_address_pointer = pc_after +
stack_check_address_offset;
+ ASSERT(Memory::uint32_at(stack_check_address_pointer) ==
+ reinterpret_cast<uint32_t>(check_code->entry()));
+ Memory::uint32_at(stack_check_address_pointer) =
+ reinterpret_cast<uint32_t>(replacement_code->entry());
}
void Deoptimizer::RevertStackCheckCodeAt(Address pc_after,
Code* check_code,
Code* replacement_code) {
- UNIMPLEMENTED();
+ const int kInstrSize = Assembler::kInstrSize;
+ ASSERT(Memory::uint32_at(pc_after - kInstrSize) == 0xe12fff3c);
+ ASSERT(Memory::uint8_at(pc_after - kInstrSize - 1) == 0xe5);
+ ASSERT(Memory::uint8_at(pc_after - kInstrSize - 2) == 0x9f);
+
+ // Replace NOP wi th conditional jump.
+ CodePatcher patcher(pc_after - 3 * kInstrSize, 1);
+ patcher.masm()->b(+4, cs);
+
+ // Replace the stack check address in the constant pool
+ // with the entry address of the replacement code.
+ uint32_t stack_check_address_offset = Memory::uint16_at(pc_after -
+ 2 * kInstrSize) & 0xfff;
+ Address stack_check_address_pointer = pc_after +
stack_check_address_offset;
+ ASSERT(Memory::uint32_at(stack_check_address_pointer) ==
+ reinterpret_cast<uint32_t>(replacement_code->entry()));
+ Memory::uint32_at(stack_check_address_pointer) =
+ reinterpret_cast<uint32_t>(check_code->entry());
}
--
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