RISC-V: introduce RVLinkageProperties::initialize() to initialize der…

…ived members

Linkage properties have a number of members whose values can be derived from register flags.
This commit introduces a new method initialize() that computes these values based on
_registerFlags.

Linkages are expected to fill in register flags and then call initialize() to finish properties
initialization.

Signed-off-by: Jan Vrany <jan.vrany@fit.cvut.cz>

compiler/riscv/codegen/OMRLinkage.cpp

@@ -31,6 +31,58 @@
 #include "il/Node_inlines.hpp"
 #include "il/ParameterSymbol.hpp"
 
+void TR::RVLinkageProperties::initialize()
+   {
+   /*
+    * Note: following code depends on zero initialization of all members!
+    */
+
+   _numAllocatableIntegerRegisters = TR::RealRegister::LastGPR - TR::RealRegister::FirstGPR + 1;
+   _numAllocatableFloatRegisters = TR::RealRegister::LastFPR - TR::RealRegister::FirstFPR + 1;
+
+   _firstIntegerArgumentRegister = 0;
+   _numIntegerArgumentRegisters = 0;
+   _firstIntegerReturnRegister = 0;
+   int numIntegerReturnRegisters = 0;
+
+   for (auto regNum = TR::RealRegister::FirstGPR; regNum <= TR::RealRegister::LastGPR; regNum++)
+      {
+      if (_registerFlags[regNum] & RV_Reserved)
+         {
+         _numAllocatableIntegerRegisters--;
+         }
+      if (_registerFlags[regNum] & IntegerArgument)
+         {
+         _argumentRegisters[_firstIntegerArgumentRegister + _numIntegerArgumentRegisters++] = regNum;
+         }
+      if (_registerFlags[regNum] & IntegerReturn)
+         {
+         _returnRegisters[_firstIntegerReturnRegister + numIntegerReturnRegisters++] = regNum;
+         }
+      }
+
+   _firstFloatArgumentRegister = _firstIntegerArgumentRegister + _numIntegerArgumentRegisters;
+   _numFloatArgumentRegisters = 0;
+   _firstFloatReturnRegister = _firstIntegerArgumentRegister + numIntegerReturnRegisters;
+   int numFloatReturnRegisters = 0;
+
+   for (auto regNum = TR::RealRegister::FirstFPR; regNum <= TR::RealRegister::LastFPR; regNum++)
+         {
+         if (_registerFlags[regNum] & RV_Reserved)
+            {
+            _numAllocatableFloatRegisters--;
+            }
+         if (_registerFlags[regNum] & FloatArgument)
+            {
+            _argumentRegisters[_firstFloatArgumentRegister + _numFloatArgumentRegisters++] = regNum;
+            }
+         if (_registerFlags[regNum] & FloatReturn)
+            {
+            _returnRegisters[_firstFloatReturnRegister + numFloatReturnRegisters++] = regNum;
+            }
+         }
+   }
+
 void OMR::RV::Linkage::mapStack(TR::ResolvedMethodSymbol *method)
    {
    /* do nothing */

compiler/riscv/codegen/OMRLinkage.hpp

@@ -292,9 +292,16 @@ struct RVLinkageProperties
    int32_t getOffsetToFirstLocal() const {return _offsetToFirstLocal;}
 
    uint32_t getNumberOfDependencyGPRegisters() const {return _numberOfDependencyGPRegisters;}
-   };
 
-}
+   /**
+    * @brief Initialize derived properties from register flags. This *must* be called
+    * after _registerFlags are populated.
+    */
+   void initialize();
+
+   }; // struct RVLinkageProperties
+
+}; // namespace TR
 
 namespace OMR
 {

compiler/riscv/codegen/RVSystemLinkage.cpp

@@ -134,42 +134,6 @@ TR::RVSystemLinkage::RVSystemLinkage(TR::CodeGenerator *cg)
    _properties._registerFlags[TR::RealRegister::ft10] = 0;
    _properties._registerFlags[TR::RealRegister::ft11] = 0;
 
-
-   _properties._numIntegerArgumentRegisters  = 8;
-   _properties._firstIntegerArgumentRegister = 0;
-
-   _properties._argumentRegisters[0]  = TR::RealRegister::a0;
-   _properties._argumentRegisters[1]  = TR::RealRegister::a1;
-   _properties._argumentRegisters[2]  = TR::RealRegister::a2;
-   _properties._argumentRegisters[3]  = TR::RealRegister::a3;
-   _properties._argumentRegisters[4]  = TR::RealRegister::a4;
-   _properties._argumentRegisters[5]  = TR::RealRegister::a5;
-   _properties._argumentRegisters[6]  = TR::RealRegister::a6;
-   _properties._argumentRegisters[7]  = TR::RealRegister::a7;
-
-   _properties._firstIntegerReturnRegister = 0;
-   _properties._returnRegisters[0]  = TR::RealRegister::a0;
-   _properties._returnRegisters[1]  = TR::RealRegister::a1;
-
-   _properties._numFloatArgumentRegisters    = 8;
-   _properties._firstFloatArgumentRegister   = 8;
-
-   _properties._argumentRegisters[8+0]  = TR::RealRegister::fa0;
-   _properties._argumentRegisters[8+1]  = TR::RealRegister::fa1;
-   _properties._argumentRegisters[8+2]  = TR::RealRegister::fa2;
-   _properties._argumentRegisters[8+3]  = TR::RealRegister::fa3;
-   _properties._argumentRegisters[8+4]  = TR::RealRegister::fa4;
-   _properties._argumentRegisters[8+5]  = TR::RealRegister::fa5;
-   _properties._argumentRegisters[8+6]  = TR::RealRegister::fa6;
-   _properties._argumentRegisters[8+7]  = TR::RealRegister::fa7;
-
-   _properties._firstFloatReturnRegister   = 2;
-   _properties._returnRegisters[2+0]  = TR::RealRegister::fa0;
-   _properties._returnRegisters[2+1]  = TR::RealRegister::fa1;
-
-   _properties._numAllocatableIntegerRegisters = 7 + 11 + 6; // t0-t6 + s1-s11 + a2-a7
-   _properties._numAllocatableFloatRegisters   = 32;
-
    _properties._methodMetaDataRegister      = TR::RealRegister::NoReg;
    _properties._stackPointerRegister        = TR::RealRegister::sp;
    _properties._framePointerRegister        = TR::RealRegister::s0;
@@ -178,6 +142,8 @@ TR::RVSystemLinkage::RVSystemLinkage(TR::CodeGenerator *cg)
    _properties._vtableIndexArgumentRegister = TR::RealRegister::NoReg;
    _properties._j9methodArgumentRegister    = TR::RealRegister::NoReg;
 
+   _properties.initialize();
+
    _properties._numberOfDependencyGPRegisters = 32; // To be determined
    setOffsetToFirstParm(0); // To be determined
    _properties._offsetToFirstLocal            = 0; // To be determined