Changeset 218782 in webkit for trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.h

Timestamp:

Jun 23, 2017, 7:54:02 PM (8 years ago)

Author:

[email protected]

Message:

Switch VMTraps to use halt instructions rather than breakpoint instructions
​https://bugs.webkit.org/show_bug.cgi?id=173677
Source/JavaScriptCore:

<rdar://problem/32178892>

Reviewed by JF Bastien.

Using the breakpoint instruction for VMTraps caused issues with lldb.
Since we only need some way to stop execution we can, in theory, use
any exceptioning instruction we want. I went with the halt instruction
on X86 since that is the only one byte instruction that does not
breakpoint (in my tests both 0xf1 and 0xd6 produced EXC_BREAKPOINT).
On ARM we use the data cache clearing instruction with the zero register,
which triggers a segmentation fault.

Also, update the platform code to only use signaling VMTraps
on where we have an appropriate instruction (x86 and ARM64).

• API/tests/ExecutionTimeLimitTest.cpp:

(testExecutionTimeLimit):

• assembler/ARM64Assembler.h:

(JSC::ARM64Assembler::replaceWithVMHalt):
(JSC::ARM64Assembler::dataCacheZeroVirtualAddress):
(JSC::ARM64Assembler::replaceWithBkpt): Deleted.

• assembler/ARMAssembler.h:

(JSC::ARMAssembler::replaceWithBkpt): Deleted.

• assembler/ARMv7Assembler.h:

(JSC::ARMv7Assembler::replaceWithBkpt): Deleted.

• assembler/MIPSAssembler.h:

(JSC::MIPSAssembler::replaceWithBkpt): Deleted.

• assembler/MacroAssemblerARM.h:

(JSC::MacroAssemblerARM::replaceWithBreakpoint): Deleted.

• assembler/MacroAssemblerARM64.h:

(JSC::MacroAssemblerARM64::replaceWithVMHalt):
(JSC::MacroAssemblerARM64::replaceWithBreakpoint): Deleted.

• assembler/MacroAssemblerARMv7.h:

(JSC::MacroAssemblerARMv7::storeFence):
(JSC::MacroAssemblerARMv7::replaceWithBreakpoint): Deleted.

• assembler/MacroAssemblerMIPS.h:

(JSC::MacroAssemblerMIPS::replaceWithBreakpoint): Deleted.

• assembler/MacroAssemblerX86Common.h:

(JSC::MacroAssemblerX86Common::replaceWithVMHalt):
(JSC::MacroAssemblerX86Common::replaceWithBreakpoint): Deleted.

• assembler/X86Assembler.h:

(JSC::X86Assembler::replaceWithHlt):
(JSC::X86Assembler::replaceWithInt3): Deleted.

• dfg/DFGJumpReplacement.cpp:

(JSC::DFG::JumpReplacement::installVMTrapBreakpoint):

• runtime/VMTraps.cpp:

(JSC::SignalContext::SignalContext):
(JSC::installSignalHandler):
(JSC::SignalContext::adjustPCToPointToTrappingInstruction): Deleted.

• wasm/WasmFaultSignalHandler.cpp:

(JSC::Wasm::enableFastMemory):

Source/WTF:

<rdar://problem/32178892>

Reviewed by JF Bastien.

Remove the Trap signal handler code since it plays badly with lldb and combine
SIGBUS with SIGSEGV since distiguishing them is generally non-portable.

Also, update the platform code to only use signaling VMTraps
on where we have an appropriate instruction (x86 and ARM64).

• wtf/Platform.h:
• wtf/threads/Signals.cpp:

(WTF::fromMachException):
(WTF::toMachMask):
(WTF::installSignalHandler):
(WTF::jscSignalHandler):

• wtf/threads/Signals.h:

(WTF::toSystemSignal):
(WTF::fromSystemSignal):

Tools:

Reviewed by JF Bastien.

• TestWebKitAPI/Tests/WTF/ThreadMessages.cpp:

(TEST):

File:

• trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.h (modified) (1 diff)

trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.h

@@ -3804 +3804 @@
 #endif
 
-    static void replaceWithBreakpoint(CodeLocationLabel instructionStart)
-    {
-        X86Assembler::replaceWithInt3(instructionStart.executableAddress());
+    static void replaceWithVMHalt(CodeLocationLabel instructionStart)
+    {
+        X86Assembler::replaceWithHlt(instructionStart.executableAddress());
     }