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Bug 1609229: Always use computed goto r=froydnj

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Differential Revision: https://phabricator.services.mozilla.com/D59927

--HG--
extra : moz-landing-system : lando
This commit is contained in:
Iain Ireland 2020-01-16 16:33:57 +00:00
parent d8480acf44
commit c294388d05
1 changed files with 4 additions and 29 deletions
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33
js/src/vm/Interpreter.cpp
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@ -1652,20 +1652,12 @@ void js::ReportInNotObjectError(JSContext* cx, HandleValue lref, int lindex,
static MOZ_NEVER_INLINE JS_HAZ_JSNATIVE_CALLER bool Interpret(JSContext* cx,
RunState& state) {
/*
* Define macros for an interpreter loop. Opcode dispatch may be either by a
* switch statement or by indirect goto (aka a threaded interpreter), depending
* on compiler support.
*
* Threaded interpretation appears to be well-supported by GCC 3 and higher.
* IBM's C compiler when run with the right options (e.g., -qlanglvl=extended)
* also supports threading. Ditto the SunPro C compiler.
* Define macros for an interpreter loop. Opcode dispatch is done by
* indirect goto (aka a threaded interpreter), which is technically
* non-standard but is supported by all of our supported compilers.
*/
#if (defined(__GNUC__) || (__IBMC__ >= 700 && defined __IBM_COMPUTED_GOTO) || \
__SUNPRO_C >= 0x570)
// Non-standard but faster indirect-goto-based dispatch.
# define INTERPRETER_LOOP()
# define CASE(OP) label_##OP:
# define PSEUDO_CASE(NAME) CASE(NAME)
# define DEFAULT() \
label_default:
# define DISPATCH_TO(OP) goto* addresses[(OP)]
@ -1684,23 +1676,6 @@ static MOZ_NEVER_INLINE JS_HAZ_JSNATIVE_CALLER bool Interpret(JSContext* cx,
FOR_EACH_TRAILING_UNUSED_OPCODE(TRAILING_LABEL)
# undef TRAILING_LABEL
};
#else
// Portable switch-based dispatch.
# define INTERPRETER_LOOP() \
the_switch: \
switch (switchOp)
# define CASE(OP) case jsbytecode(JSOp::OP):
# define PSEUDO_CASE(NAME) case NAME:
# define DEFAULT() default:
# define DISPATCH_TO(OP) \
JS_BEGIN_MACRO \
switchOp = (OP); \
goto the_switch; \
JS_END_MACRO
// This variable is effectively a parameter to the_switch.
jsbytecode switchOp;
#endif
/*
* Increment REGS.pc by N, load the opcode at that position,
@ -1860,7 +1835,7 @@ static MOZ_NEVER_INLINE JS_HAZ_JSNATIVE_CALLER bool Interpret(JSContext* cx,
ADVANCE_AND_DISPATCH(0);
INTERPRETER_LOOP() {
PSEUDO_CASE(EnableInterruptsPseudoOpcode) {
CASE(EnableInterruptsPseudoOpcode) {
bool moreInterrupts = false;
jsbytecode op = *REGS.pc;