Cleanup and document MachineLocation.

Clarify documentation and API to make the difference between register and
register-indirect addressed locations more explicit. Put in a comment
to point out that with the current implementation we cannot specify
a register-indirect location with offset 0 (a breg 0 in DWARF).
No functionality change intended.

rdar://problem/13658587

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180641 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Adrian Prantl 2013-04-26 21:57:17 +00:00
parent f1d9fe9d04
commit 13131e62fc
3 changed files with 15 additions and 4 deletions

View File

@ -9,7 +9,7 @@
// The MachineLocation class is used to represent a simple location in a machine
// frame. Locations will be one of two forms; a register or an address formed
// from a base address plus an offset. Register indirection can be specified by
// using an offset of zero.
// explicitly passing an offset to the constructor.
//
// The MachineMove class is used to represent abstract move operations in the
// prolog/epilog of a compiled function. A collection of these objects can be
@ -37,8 +37,10 @@ public:
};
MachineLocation()
: IsRegister(false), Register(0), Offset(0) {}
/// Create a direct register location.
explicit MachineLocation(unsigned R)
: IsRegister(true), Register(R), Offset(0) {}
/// Create a register-indirect location with an offset.
MachineLocation(unsigned R, int O)
: IsRegister(false), Register(R), Offset(O) {}
@ -48,17 +50,20 @@ public:
}
// Accessors
bool isIndirect() const { return !IsRegister; }
bool isReg() const { return IsRegister; }
unsigned getReg() const { return Register; }
int getOffset() const { return Offset; }
void setIsRegister(bool Is) { IsRegister = Is; }
void setRegister(unsigned R) { Register = R; }
void setOffset(int O) { Offset = O; }
/// Make this location a direct register location.
void set(unsigned R) {
IsRegister = true;
Register = R;
Offset = 0;
}
/// Make this location a register-indirect+offset location.
void set(unsigned R, int O) {
IsRegister = false;
Register = R;

View File

@ -813,7 +813,7 @@ void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc) const {
// caller might be in the middle of an dwarf expression. We should
// probably assert that Reg >= 0 once debug info generation is more mature.
if (int Offset = MLoc.getOffset()) {
if (MLoc.isIndirect()) {
if (Reg < 32) {
OutStreamer.AddComment(
dwarf::OperationEncodingString(dwarf::DW_OP_breg0 + Reg));
@ -824,7 +824,7 @@ void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc) const {
OutStreamer.AddComment(Twine(Reg));
EmitULEB128(Reg);
}
EmitSLEB128(Offset);
EmitSLEB128(MLoc.getOffset());
} else {
if (Reg < 32) {
OutStreamer.AddComment(

View File

@ -1131,6 +1131,12 @@ static DotDebugLocEntry getDebugLocEntry(AsmPrinter *Asm,
}
if (MI->getOperand(0).isReg() && MI->getOperand(1).isImm()) {
MachineLocation MLoc;
// TODO: Currently an offset of 0 in a DBG_VALUE means
// we need to generate a direct register value.
// There is no way to specify an indirect value with offset 0.
if (MI->getOperand(1).getImm() == 0)
MLoc.set(MI->getOperand(0).getReg());
else
MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm());
return DotDebugLocEntry(FLabel, SLabel, MLoc, Var);
}