+ SmallVector<CCValAssign, 4> PendingLocs;
+
+ // ByValInfo and SmallVector<ByValInfo, 4> ByValRegs:
+ //
+ // Vector of ByValInfo instances (ByValRegs) is introduced for byval registers
+ // tracking.
+ // Or, in another words it tracks byval parameters that are stored in
+ // general purpose registers.
+ //
+ // For 4 byte stack alignment,
+ // instance index means byval parameter number in formal
+ // arguments set. Assume, we have some "struct_type" with size = 4 bytes,
+ // then, for function "foo":
+ //
+ // i32 foo(i32 %p, %struct_type* %r, i32 %s, %struct_type* %t)
+ //
+ // ByValRegs[0] describes how "%r" is stored (Begin == r1, End == r2)
+ // ByValRegs[1] describes how "%t" is stored (Begin == r3, End == r4).
+ //
+ // In case of 8 bytes stack alignment,
+ // ByValRegs may also contain information about wasted registers.
+ // In function shown above, r3 would be wasted according to AAPCS rules.
+ // And in that case ByValRegs[1].Waste would be "true".
+ // ByValRegs vector size still would be 2,
+ // while "%t" goes to the stack: it wouldn't be described in ByValRegs.
+ //
+ // Supposed use-case for this collection:
+ // 1. Initially ByValRegs is empty, InRegsParamsProcessed is 0.
+ // 2. HandleByVal fillups ByValRegs.
+ // 3. Argument analysis (LowerFormatArguments, for example). After
+ // some byval argument was analyzed, InRegsParamsProcessed is increased.
+ struct ByValInfo {
+ ByValInfo(unsigned B, unsigned E, bool IsWaste = false) :
+ Begin(B), End(E), Waste(IsWaste) {}
+ // First register allocated for current parameter.
+ unsigned Begin;
+
+ // First after last register allocated for current parameter.
+ unsigned End;
+
+ // Means that current range of registers doesn't belong to any
+ // parameters. It was wasted due to stack alignment rules.
+ // For more information see:
+ // AAPCS, 5.5 Parameter Passing, Stage C, C.3.
+ bool Waste;
+ };
+ SmallVector<ByValInfo, 4 > ByValRegs;
+
+ // InRegsParamsProcessed - shows how many instances of ByValRegs was proceed
+ // during argument analysis.
+ unsigned InRegsParamsProcessed;
+
+protected:
+ ParmContext CallOrPrologue;
+