Rename STACK_REGISTERS -> DISALLOWED_REGISTERS

Summary: On x86-64 these are the same concepts (the set of disallowed registers is the same set of registers as those that are used for the stack). However on aarch64, we want XZR to also be on the list of disallowed registers, which is not explicitly a stack register, but rather something that has special meaning.

Reviewed By: alexmalyshev

Differential Revision: D87260451

fbshipit-source-id: 78602c1da4f4719d06e5d5d0f14258092bafb90c

Author: kddnewton

cinderx/Jit/codegen/arch/unknown.h

@@ -227,8 +227,8 @@ constexpr PhyRegisterSet ALL_VECD_REGISTERS =
 constexpr PhyRegisterSet ALL_REGISTERS = ALL_GP_REGISTERS | ALL_VECD_REGISTERS;
 #undef ADD_REG
 
-constexpr PhyRegisterSet STACK_REGISTERS = PhyRegisterSet();
-constexpr PhyRegisterSet INIT_REGISTERS = ALL_REGISTERS - STACK_REGISTERS;
+constexpr PhyRegisterSet DISALLOWED_REGISTERS = PhyRegisterSet();
+constexpr PhyRegisterSet INIT_REGISTERS = ALL_REGISTERS - DISALLOWED_REGISTERS;
 constexpr PhyRegisterSet CALLEE_SAVE_REGS = PhyRegisterSet();
 constexpr PhyRegisterSet CALLER_SAVE_REGS = INIT_REGISTERS - CALLEE_SAVE_REGS;
 

cinderx/Jit/codegen/arch/x86_64.h

@@ -296,9 +296,9 @@ constexpr PhyRegisterSet ALL_VECD_REGISTERS =
 constexpr PhyRegisterSet ALL_REGISTERS = ALL_GP_REGISTERS | ALL_VECD_REGISTERS;
 #undef ADD_REG
 
-constexpr PhyRegisterSet STACK_REGISTERS = PhyRegisterSet(RSP) | RBP;
+constexpr PhyRegisterSet DISALLOWED_REGISTERS = PhyRegisterSet(RSP) | RBP;
 
-constexpr PhyRegisterSet INIT_REGISTERS = ALL_REGISTERS - STACK_REGISTERS;
+constexpr PhyRegisterSet INIT_REGISTERS = ALL_REGISTERS - DISALLOWED_REGISTERS;
 
 constexpr PhyRegisterSet CALLER_SAVE_REGS = PhyRegisterSet(RAX) | RCX | RDX |
     RSI | RDI | R8 | R9 | R10 | R11 | ALL_VECD_REGISTERS;

cinderx/Jit/lir/regalloc.cpp

@@ -35,10 +35,10 @@ struct LiveRangeCompare {
 };
 
 void markDisallowedRegisters(std::vector<LIRLocation>& locs) {
-  auto stack_registers = STACK_REGISTERS;
-  while (!stack_registers.Empty()) {
-    auto reg = stack_registers.GetFirst();
-    stack_registers.RemoveFirst();
+  auto disallowed_registers = DISALLOWED_REGISTERS;
+  while (!disallowed_registers.Empty()) {
+    auto reg = disallowed_registers.GetFirst();
+    disallowed_registers.RemoveFirst();
 
     locs[reg.loc] = START_LOCATION;
   }