Changeset 253320 in webkit for trunk/Source/JavaScriptCore/assembler

Timestamp:

Dec 9, 2019, 9:02:57 PM (5 years ago)

Author:

[email protected]

Message:

Fix the x86_64 probe so that we can get a full stack trace with libunwind and lldb.
​https://bugs.webkit.org/show_bug.cgi?id=205050

Reviewed by Michael Saboff.

Before this patch, the stack trace from inside a probe function is cut off at ctiMasmProbeTrampoline:

(lldb) bt

• thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0xbbadbeef)

...
frame #4: 0x0000000100824607 JavaScriptCore`WTF::Function<void (JSC::Probe::Context&)>::operator(this=0x000000010b88bd00, in=0x00007ffeefbfd400)(JSC::Probe::Context&) const at Function.h:79:35
frame #5: 0x0000000100823996 JavaScriptCore`JSC::stdFunctionCallback(context=0x00007ffeefbfd400) at MacroAssembler.cpp:53:5
frame #6: 0x000000010082701e JavaScriptCore`JSC::Probe::executeProbe(state=0x00007ffeefbfd480) at ProbeContext.cpp:51:5
frame #7: 0x000000010082614b JavaScriptCore`ctiMasmProbeTrampoline + 299

(lldb)

After this patch, we'll now get the full stack trace from inside the probe function:

(lldb) bt

• thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0xbbadbeef)

...
frame #4: 0x0000000100826d17 JavaScriptCore`WTF::Function<void (JSC::Probe::Context&)>::operator(this=0x0000000106b878f8, in=0x00007ffeefbfd400)(JSC::Probe::Context&) const at Function.h:79:35
frame #5: 0x0000000100826106 JavaScriptCore`JSC::stdFunctionCallback(context=0x00007ffeefbfd400) at MacroAssembler.cpp:53:5
frame #6: 0x000000010082986e JavaScriptCore`JSC::Probe::executeProbe(state=0x00007ffeefbfd480) at ProbeContext.cpp:51:5
frame #7: 0x00000001008289a2 JavaScriptCore`ctiMasmProbeTrampoline + 338
frame #8: 0x0000466db28025be
frame #9: 0x0000000100754ffc JavaScriptCore`llint_entry at LowLevelInterpreter.asm:994
frame #10: 0x0000000100738173 JavaScriptCore`vmEntryToJavaScript at LowLevelInterpreter64.asm:307
frame #11: 0x0000000101489307 JavaScriptCore`JSC::JITCode::execute(this=0x0000000106ba1520, vm=0x0000000106d00000, protoCallFrame=0x00007ffeefbfd9b8) at JITCodeInlines.h:38:38
frame #12: 0x0000000101488982 JavaScriptCore`JSC::Interpreter::executeProgram(this=0x0000000106bfd1f8, source=0x00007ffeefbff090, (null)=0x000000010d0e0000, thisObj=0x000000010d0e8020) at Interpreter.cpp:847:51
frame #13: 0x00000001017d1f9c JavaScriptCore`JSC::evaluate(globalObject=0x000000010d0e0000, source=0x00007ffeefbff090, thisValue=JSValue @ 0x00007ffeefbfef60, returnedException=0x00007ffeefbff0b0) at Completion.cpp:146:38
frame #14: 0x000000010005838f jsc`runWithOptions(globalObject=0x000000010d0e0000, options=0x00007ffeefbff620, success=0x00007ffeefbff48b) at jsc.cpp:2670:35
frame #15: 0x000000010002a0da jsc`jscmain(this=0x00007ffeefbff5a0, vm=0x0000000106d00000, globalObject=0x000000010d0e0000, success=0x00007ffeefbff48b)::$_6::operator()(JSC::VM&, GlobalObject*, bool&) const at jsc.cpp:3157:13
frame #16: 0x0000000100006eff jsc`int runJSC<jscmain(int, char)::$_6>(options=0x00007ffeefbff620, isWorker=false, func=0x00007ffeefbff5a0)::$_6 const&) at jsc.cpp:3003:9
frame #17: 0x0000000100005988 jsc`jscmain(argc=10, argv=0x00007ffeefbff6c8) at jsc.cpp:3150:18
frame #18: 0x000000010000575e jsc`main(argc=10, argv=0x00007ffeefbff6c8) at jsc.cpp:2498:15
frame #19: 0x00007fff6cfc4da9 libdyld.dylib`start + 1
frame #20: 0x00007fff6cfc4da9 libdyld.dylib`start + 1

(lldb)

The difference is that the x86_64 ctiMasmProbeTrampoline now uses the standard
function prologue, and keeps %rbp pointing to trampoline function's semblance of
a frame that libunwind can understand while it calls the probe function.

• assembler/MacroAssemblerX86Common.cpp:

File:

• trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.cpp (modified) (4 diffs)

trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.cpp

@@ -1 +1 @@
 /*
- * Copyright (C) 2013-2018 Apple Inc. All rights reserved.
+ * Copyright (C) 2013-2019 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -518 +518 @@
     SYMBOL_STRING(ctiMasmProbeTrampoline) ":" "\n"
 
+    "pushq %rbp" "\n"
+    "movq  %rsp, %rbp" "\n"
+
     "pushfq" "\n"
 
     // MacroAssemblerX86Common::probe() has already generated code to store some values.
-    // Together with the rflags pushed above, the top of stack now looks like this:
-    //     rsp[0 * ptrSize]: rflags
-    //     rsp[1 * ptrSize]: return address / saved rip
-    //     rsp[2 * ptrSize]: saved rbx
-    //     rsp[3 * ptrSize]: saved rdx
-    //     rsp[4 * ptrSize]: saved rcx
-    //     rsp[5 * ptrSize]: saved rax
+    // Together with the rbp and rflags pushed above, the top of stack now looks like this:
+    //     rbp[-1 * ptrSize]: rflags
+    //     rbp[0 * ptrSize]: rbp / previousCallFrame
+    //     rbp[1 * ptrSize]: return address / saved rip
+    //     rbp[2 * ptrSize]: saved rbx
+    //     rbp[3 * ptrSize]: saved rdx
+    //     rbp[4 * ptrSize]: saved rcx
+    //     rbp[5 * ptrSize]: saved rax
     //
     // Incoming registers contain:
@@ -535 +539 @@
     //     rax: scratch (was ctiMasmProbeTrampoline)
 
-    "movq %rsp, %rax" "\n"
     "subq $" STRINGIZE_VALUE_OF(PROBE_SIZE + OUT_SIZE) ", %rsp" "\n"
 
@@ -542 +545 @@
     // Since sp points to the Probe::State, we've ensured that it's protected from interrupts before we initialize it.
 
-    "movq %rbp, " STRINGIZE_VALUE_OF(PROBE_CPU_EBP_OFFSET) "(%rsp)" "\n"
-    "movq %rsp, %rbp" "\n" // Save the Probe::State*.
-
-    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_EXECUTOR_OFFSET) "(%rbp)" "\n"
-    "movq %rdx, " STRINGIZE_VALUE_OF(PROBE_PROBE_FUNCTION_OFFSET) "(%rbp)" "\n"
-    "movq %rbx, " STRINGIZE_VALUE_OF(PROBE_ARG_OFFSET) "(%rbp)" "\n"
-    "movq %rsi, " STRINGIZE_VALUE_OF(PROBE_CPU_ESI_OFFSET) "(%rbp)" "\n"
-    "movq %rdi, " STRINGIZE_VALUE_OF(PROBE_CPU_EDI_OFFSET) "(%rbp)" "\n"
-
-    "movq 0 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rax), %rcx" "\n"
-    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EFLAGS_OFFSET) "(%rbp)" "\n"
-    "movq 1 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rax), %rcx" "\n"
-    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EIP_OFFSET) "(%rbp)" "\n"
-    "movq 2 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rax), %rcx" "\n"
-    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EBX_OFFSET) "(%rbp)" "\n"
-    "movq 3 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rax), %rcx" "\n"
-    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EDX_OFFSET) "(%rbp)" "\n"
-    "movq 4 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rax), %rcx" "\n"
-    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_ECX_OFFSET) "(%rbp)" "\n"
-    "movq 5 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rax), %rcx" "\n"
-    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EAX_OFFSET) "(%rbp)" "\n"
-
-    "movq %rax, %rcx" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_EXECUTOR_OFFSET) "(%rsp)" "\n"
+    "movq %rdx, " STRINGIZE_VALUE_OF(PROBE_PROBE_FUNCTION_OFFSET) "(%rsp)" "\n"
+    "movq %rbx, " STRINGIZE_VALUE_OF(PROBE_ARG_OFFSET) "(%rsp)" "\n"
+    "movq %rsi, " STRINGIZE_VALUE_OF(PROBE_CPU_ESI_OFFSET) "(%rsp)" "\n"
+    "movq %rdi, " STRINGIZE_VALUE_OF(PROBE_CPU_EDI_OFFSET) "(%rsp)" "\n"
+
+    "movq -1 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rbp), %rcx" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EFLAGS_OFFSET) "(%rsp)" "\n"
+    "movq 0 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rbp), %rcx" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EBP_OFFSET) "(%rsp)" "\n"
+    "movq 1 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rbp), %rcx" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EIP_OFFSET) "(%rsp)" "\n"
+    "movq 2 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rbp), %rcx" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EBX_OFFSET) "(%rsp)" "\n"
+    "movq 3 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rbp), %rcx" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EDX_OFFSET) "(%rsp)" "\n"
+    "movq 4 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rbp), %rcx" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_ECX_OFFSET) "(%rsp)" "\n"
+    "movq 5 * " STRINGIZE_VALUE_OF(PTR_SIZE) "(%rbp), %rcx" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_EAX_OFFSET) "(%rsp)" "\n"
+
+    "movq %rbp, %rcx" "\n"
     "addq $" STRINGIZE_VALUE_OF(6 * PTR_SIZE) ", %rcx" "\n"
-    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_ESP_OFFSET) "(%rbp)" "\n"
-
-    "movq %r8, " STRINGIZE_VALUE_OF(PROBE_CPU_R8_OFFSET) "(%rbp)" "\n"
-    "movq %r9, " STRINGIZE_VALUE_OF(PROBE_CPU_R9_OFFSET) "(%rbp)" "\n"
-    "movq %r10, " STRINGIZE_VALUE_OF(PROBE_CPU_R10_OFFSET) "(%rbp)" "\n"
-    "movq %r11, " STRINGIZE_VALUE_OF(PROBE_CPU_R11_OFFSET) "(%rbp)" "\n"
-    "movq %r12, " STRINGIZE_VALUE_OF(PROBE_CPU_R12_OFFSET) "(%rbp)" "\n"
-    "movq %r13, " STRINGIZE_VALUE_OF(PROBE_CPU_R13_OFFSET) "(%rbp)" "\n"
-    "movq %r14, " STRINGIZE_VALUE_OF(PROBE_CPU_R14_OFFSET) "(%rbp)" "\n"
-    "movq %r15, " STRINGIZE_VALUE_OF(PROBE_CPU_R15_OFFSET) "(%rbp)" "\n"
-
-    "movq %xmm0, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM0_OFFSET) "(%rbp)" "\n"
-    "movq %xmm1, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM1_OFFSET) "(%rbp)" "\n"
-    "movq %xmm2, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM2_OFFSET) "(%rbp)" "\n"
-    "movq %xmm3, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM3_OFFSET) "(%rbp)" "\n"
-    "movq %xmm4, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM4_OFFSET) "(%rbp)" "\n"
-    "movq %xmm5, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM5_OFFSET) "(%rbp)" "\n"
-    "movq %xmm6, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM6_OFFSET) "(%rbp)" "\n"
-    "movq %xmm7, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM7_OFFSET) "(%rbp)" "\n"
-    "movq %xmm8, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM8_OFFSET) "(%rbp)" "\n"
-    "movq %xmm9, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM9_OFFSET) "(%rbp)" "\n"
-    "movq %xmm10, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM10_OFFSET) "(%rbp)" "\n"
-    "movq %xmm11, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM11_OFFSET) "(%rbp)" "\n"
-    "movq %xmm12, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM12_OFFSET) "(%rbp)" "\n"
-    "movq %xmm13, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM13_OFFSET) "(%rbp)" "\n"
-    "movq %xmm14, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM14_OFFSET) "(%rbp)" "\n"
-    "movq %xmm15, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM15_OFFSET) "(%rbp)" "\n"
-
-    "movq %rbp, %rdi" "\n" // the Probe::State* arg.
-    "call *" STRINGIZE_VALUE_OF(PROBE_EXECUTOR_OFFSET) "(%rbp)" "\n"
+    "movq %rcx, " STRINGIZE_VALUE_OF(PROBE_CPU_ESP_OFFSET) "(%rsp)" "\n"
+
+    "movq %r8, " STRINGIZE_VALUE_OF(PROBE_CPU_R8_OFFSET) "(%rsp)" "\n"
+    "movq %r9, " STRINGIZE_VALUE_OF(PROBE_CPU_R9_OFFSET) "(%rsp)" "\n"
+    "movq %r10, " STRINGIZE_VALUE_OF(PROBE_CPU_R10_OFFSET) "(%rsp)" "\n"
+    "movq %r11, " STRINGIZE_VALUE_OF(PROBE_CPU_R11_OFFSET) "(%rsp)" "\n"
+    "movq %r12, " STRINGIZE_VALUE_OF(PROBE_CPU_R12_OFFSET) "(%rsp)" "\n"
+    "movq %r13, " STRINGIZE_VALUE_OF(PROBE_CPU_R13_OFFSET) "(%rsp)" "\n"
+    "movq %r14, " STRINGIZE_VALUE_OF(PROBE_CPU_R14_OFFSET) "(%rsp)" "\n"
+    "movq %r15, " STRINGIZE_VALUE_OF(PROBE_CPU_R15_OFFSET) "(%rsp)" "\n"
+
+    "movq %xmm0, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM0_OFFSET) "(%rsp)" "\n"
+    "movq %xmm1, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM1_OFFSET) "(%rsp)" "\n"
+    "movq %xmm2, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM2_OFFSET) "(%rsp)" "\n"
+    "movq %xmm3, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM3_OFFSET) "(%rsp)" "\n"
+    "movq %xmm4, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM4_OFFSET) "(%rsp)" "\n"
+    "movq %xmm5, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM5_OFFSET) "(%rsp)" "\n"
+    "movq %xmm6, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM6_OFFSET) "(%rsp)" "\n"
+    "movq %xmm7, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM7_OFFSET) "(%rsp)" "\n"
+    "movq %xmm8, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM8_OFFSET) "(%rsp)" "\n"
+    "movq %xmm9, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM9_OFFSET) "(%rsp)" "\n"
+    "movq %xmm10, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM10_OFFSET) "(%rsp)" "\n"
+    "movq %xmm11, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM11_OFFSET) "(%rsp)" "\n"
+    "movq %xmm12, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM12_OFFSET) "(%rsp)" "\n"
+    "movq %xmm13, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM13_OFFSET) "(%rsp)" "\n"
+    "movq %xmm14, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM14_OFFSET) "(%rsp)" "\n"
+    "movq %xmm15, " STRINGIZE_VALUE_OF(PROBE_CPU_XMM15_OFFSET) "(%rsp)" "\n"
+
+    "movq %rsp, %rdi" "\n" // the Probe::State* arg.
+    "call *" STRINGIZE_VALUE_OF(PROBE_EXECUTOR_OFFSET) "(%rsp)" "\n"
 
     // Make sure the Probe::State is entirely below the result stack pointer so
     // that register values are still preserved when we call the initializeStack
     // function.
+    "movq %rsp, %rbp" "\n"
     "movq $" STRINGIZE_VALUE_OF(PROBE_SIZE + OUT_SIZE) ", %rcx" "\n"
-    "movq %rbp, %rax" "\n"
+    "movq %rsp, %rax" "\n"
     "movq " STRINGIZE_VALUE_OF(PROBE_CPU_ESP_OFFSET) "(%rbp), %rdx" "\n"
     "addq %rcx, %rax" "\n"