fourthTier: Implement a probe mechanism for JIT generated code.
https://bugs.webkit.org/show_bug.cgi?id=115705.
Reviewed by Geoffrey Garen.
The probe is in the form of a MacroAssembler pseudo instruction.
It takes 3 arguments: a ProbeFunction, and 2 void* args.
When inserted into the JIT at some code generation site, the probe
pseudo "instruction" will emit a minimal amount of code to save the
stack pointer, 1 (or more) scratch register(s), and the probe
arguments into a ProbeContext record on the stack. The emitted code
will then call a probe trampoline to do the rest of the work, which
consists of:
- saving the remaining registers into the ProbeContext.
- calling the ProbeFunction, and passing it the ProbeContext pointer.
- restoring the registers from the ProbeContext after the ProbeFunction
returns, and then returning to the JIT generated code.
The ProbeContext is stack allocated and is only valid for the duration
that the ProbeFunction is executing.
If the user supplied ProbeFunction alters the register values in the
ProbeContext, the new values will be installed into the registers upon
returning from the probe. This can be useful for some debugging or
testing purposes.
The probe mechanism is built conditional on USE(MASM_PROBE) which is
defined in config.h. USE(MASM_PROBE) will off by default.
This changeset only implements the probe mechanism for X86 and X86_64.
- CMakeLists.txt:
- GNUmakefile.list.am:
- JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
- JavaScriptCore.vcxproj/JavaScriptCore.vcxproj:
- JavaScriptCore.vcxproj/JavaScriptCore.vcxproj.filters:
- JavaScriptCore.xcodeproj/project.pbxproj:
- Target.pri:
- assembler/MacroAssembler.h:
(MacroAssembler):
(JSC::MacroAssembler::shouldBlind):
(JSC::MacroAssembler::store32):
- assembler/MacroAssemblerX86.h:
(MacroAssemblerX86):
(JSC::MacroAssemblerX86::trustedImm32FromPtr):
(JSC::MacroAssemblerX86::probe):
- assembler/MacroAssemblerX86Common.cpp: Added.
(JSC::MacroAssemblerX86Common::ProbeContext::dumpCPURegisters):
- CPU specific register dumper called by ProbeContext::dump().
(JSC::MacroAssemblerX86Common::ProbeContext::dump):
- Prints the ProbeContext to the DataLog.
- assembler/MacroAssemblerX86Common.h:
(MacroAssemblerX86Common):
(CPUState): Added.
(ProbeContext): Added.
- assembler/MacroAssemblerX86_64.h:
(MacroAssemblerX86_64):
(JSC::MacroAssemblerX86_64::trustedImm64FromPtr):
(JSC::MacroAssemblerX86_64::probe):
- assembler/X86Assembler.h:
- config.h: Added WTF_USE_MASM_PROBE flag.
- jit/JITStubs.cpp:
- jit/JITStubs.h:
- jit/JITStubsX86.h:
- jit/JITStubsX86Common.h: Added.
- jit/JITStubsX86_64.h:
