Reviewers: Søren Gjesse,
Description:
ARM: Implement PatchStackCheckCodeAt and RevertStackCheckCode.
This patch also adds platform independent CPU instruction cache flushing.
BUG=none
TEST=none
Please review this at http://codereview.chromium.org/6410029/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/arm/deoptimizer-arm.cc
M src/deoptimizer.cc
Index: src/arm/deoptimizer-arm.cc
diff --git a/src/arm/deoptimizer-arm.cc b/src/arm/deoptimizer-arm.cc
index
e05001f3c38fe228bd7ee7e6ff9b926c39a3af20..44f207a64ce4432ffc2dbdc8eea9d954d76b36da
100644
--- a/src/arm/deoptimizer-arm.cc
+++ b/src/arm/deoptimizer-arm.cc
@@ -124,14 +124,57 @@ void Deoptimizer::DeoptimizeFunction(JSFunction*
function) {
void Deoptimizer::PatchStackCheckCodeAt(Address pc_after,
Code* check_code,
Code* replacement_code) {
- UNIMPLEMENTED();
+ // The call of the stack guard check has the following form:
+ // e1 5d 00 0c cmp sp, <limit>
+ // 2a ?? ?? ?? bcs ok
+ // e5 9f c? ?? ldr ip, [pc, <stack guard address>]
+ // e1 2f ff 3c blx ip
+ ASSERT(Memory::uint32_at(pc_after - 4) == 0xe12fff3c);
+ ASSERT(Memory::uint8_at(pc_after - 5) == 0xe5);
+ ASSERT(Memory::uint8_at(pc_after - 6) == 0x9f);
+
+ // 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.
+ Memory::uint32_at(pc_after - 12) = 0xe1a00000;
+
+ // 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 - 8) &
+ 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();
+ ASSERT(Memory::uint32_at(pc_after - 4) == 0xe12fff3c);
+ ASSERT(Memory::uint8_at(pc_after - 5) == 0xe5);
+ ASSERT(Memory::uint8_at(pc_after - 6) == 0x9f);
+
+ // Replace NOP with conditional jump.
+ Memory::uint32_at(pc_after - 12) = 0x2a000001;
+
+ // 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 - 8) &
+ 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());
}
Index: src/deoptimizer.cc
diff --git a/src/deoptimizer.cc b/src/deoptimizer.cc
index
00e7d0ee2cab70655ebdf3613f34cc93de44d049..7f0781cd550e1f151905a02b005508963d1ed04f
100644
--- a/src/deoptimizer.cc
+++ b/src/deoptimizer.cc
@@ -820,11 +820,22 @@ void Deoptimizer::PatchStackCheckCode(Code*
unoptimized_code,
unoptimized_code->stack_check_table_offset();
uint32_t table_length = Memory::uint32_at(stack_check_cursor);
stack_check_cursor += kIntSize;
+ Address first_site = 0;
+ Address last_site = 0;
for (uint32_t i = 0; i < table_length; ++i) {
uint32_t pc_offset = Memory::uint32_at(stack_check_cursor + kIntSize);
Address pc_after = unoptimized_code->instruction_start() + pc_offset;
PatchStackCheckCodeAt(pc_after, check_code, replacement_code);
stack_check_cursor += 2 * kIntSize;
+ if (first_site == 0) {
+ first_site = pc_after;
+ }
+ last_site = pc_after;
+ }
+ if (table_length > 0) {
+ // Flush instruction cache for the patched code blocks.
+ uint32_t length = last_site - first_site + patch_size();
+ CPU::FlushICache(first_site - patch_size(), length);
}
}
@@ -839,11 +850,22 @@ void Deoptimizer::RevertStackCheckCode(Code*
unoptimized_code,
unoptimized_code->stack_check_table_offset();
uint32_t table_length = Memory::uint32_at(stack_check_cursor);
stack_check_cursor += kIntSize;
+ Address first_site = 0;
+ Address last_site = 0;
for (uint32_t i = 0; i < table_length; ++i) {
uint32_t pc_offset = Memory::uint32_at(stack_check_cursor + kIntSize);
Address pc_after = unoptimized_code->instruction_start() + pc_offset;
RevertStackCheckCodeAt(pc_after, check_code, replacement_code);
stack_check_cursor += 2 * kIntSize;
+ if (first_site == 0) {
+ first_site = pc_after;
+ }
+ last_site = pc_after;
+ }
+ if (table_length > 0) {
+ // Flush instruction cache for the patched code blocks.
+ uint32_t length = last_site - first_site + patch_size();
+ CPU::FlushICache(first_site - patch_size(), length);
}
}
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