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[RISCV] Remove the offset numbers from the FixedCSRFIMap. NFC #129297

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Merged
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Mar 1, 2025
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[RISCV] Remove the offset numbers from the FixedCSRFIMap. NFC #129297

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38 changes: 20 additions & 18 deletions llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -110,16 +110,16 @@ static constexpr MCPhysReg SPReg = RISCV::X2;
// The register used to hold the return address.
static constexpr MCPhysReg RAReg = RISCV::X1;

// Offsets which need to be scale by XLen representing locations of CSRs which
// are given a fixed location by save/restore libcalls or Zcmp Push/Pop.
static const std::pair<MCPhysReg, int8_t> FixedCSRFIMap[] = {
{/*ra*/ RAReg, -1}, {/*s0*/ FPReg, -2},
{/*s1*/ RISCV::X9, -3}, {/*s2*/ RISCV::X18, -4},
{/*s3*/ RISCV::X19, -5}, {/*s4*/ RISCV::X20, -6},
{/*s5*/ RISCV::X21, -7}, {/*s6*/ RISCV::X22, -8},
{/*s7*/ RISCV::X23, -9}, {/*s8*/ RISCV::X24, -10},
{/*s9*/ RISCV::X25, -11}, {/*s10*/ RISCV::X26, -12},
{/*s11*/ RISCV::X27, -13}};
// LIst of CSRs that are given a fixed location by save/restore libcalls or
// Zcmp/Xqccmp Push/Pop. The order in this table indicates the order the
// registers are saved on the stack. Zcmp uses the reverse order of save/restore
// and Xqccmp on the stack, but this is handled when offsets are calculated.
static const MCPhysReg FixedCSRFIMap[] = {
/*ra*/ RAReg, /*s0*/ FPReg, /*s1*/ RISCV::X9,
/*s2*/ RISCV::X18, /*s3*/ RISCV::X19, /*s4*/ RISCV::X20,
/*s5*/ RISCV::X21, /*s6*/ RISCV::X22, /*s7*/ RISCV::X23,
/*s8*/ RISCV::X24, /*s9*/ RISCV::X25, /*s10*/ RISCV::X26,
/*s11*/ RISCV::X27};

// For now we use x3, a.k.a gp, as pointer to shadow call stack.
// User should not use x3 in their asm.
Expand Down Expand Up @@ -371,8 +371,8 @@ static Register getMaxPushPopReg(const MachineFunction &MF,
const std::vector<CalleeSavedInfo> &CSI) {
MCRegister MaxPushPopReg;
for (auto &CS : CSI) {
if (llvm::find_if(FixedCSRFIMap, [&](auto P) {
return P.first == CS.getReg();
if (llvm::find_if(FixedCSRFIMap, [&](MCPhysReg P) {
return P == CS.getReg();
}) != std::end(FixedCSRFIMap))
MaxPushPopReg = std::max(MaxPushPopReg.id(), CS.getReg().id());
}
Expand Down Expand Up @@ -488,7 +488,7 @@ getPushOrLibCallsSavedInfo(const MachineFunction &MF,

for (const auto &CS : CSI) {
const auto *FII = llvm::find_if(
FixedCSRFIMap, [&](auto P) { return P.first == CS.getReg(); });
FixedCSRFIMap, [&](MCPhysReg P) { return P == CS.getReg(); });
if (FII != std::end(FixedCSRFIMap))
PushOrLibCallsCSI.push_back(CS);
}
Expand Down Expand Up @@ -1813,13 +1813,15 @@ bool RISCVFrameLowering::assignCalleeSavedSpillSlots(
// This might need a fixed stack slot.
if (RVFI->useSaveRestoreLibCalls(MF) || RVFI->isPushable(MF)) {
const auto *FII = llvm::find_if(
FixedCSRFIMap, [&](auto P) { return P.first == CS.getReg(); });
FixedCSRFIMap, [&](MCPhysReg P) { return P == CS.getReg(); });
unsigned RegNum = std::distance(std::begin(FixedCSRFIMap), FII);

if (FII != std::end(FixedCSRFIMap)) {
int64_t Offset;
if (RVFI->isPushable(MF))
Offset = -((FII->second + RVFI->getRVPushRegs() + 1) * (int64_t)Size);
Offset = -int64_t(RVFI->getRVPushRegs() - RegNum) * Size;
else
Offset = FII->second * (int64_t)Size;
Offset = -int64_t(RegNum + 1) * Size;

int FrameIdx = MFI.CreateFixedSpillStackObject(Size, Offset);
assert(FrameIdx < 0);
Expand Down Expand Up @@ -1888,7 +1890,7 @@ bool RISCVFrameLowering::spillCalleeSavedRegisters(
PushBuilder.addImm(0);

for (unsigned i = 0; i < PushedRegNum; i++)
PushBuilder.addUse(FixedCSRFIMap[i].first, RegState::Implicit);
PushBuilder.addUse(FixedCSRFIMap[i], RegState::Implicit);
}
} else if (const char *SpillLibCall = getSpillLibCallName(*MF, CSI)) {
// Add spill libcall via non-callee-saved register t0.
Expand Down Expand Up @@ -2043,7 +2045,7 @@ bool RISCVFrameLowering::restoreCalleeSavedRegisters(
PopBuilder.addImm(0);

for (unsigned i = 0; i < RVFI->getRVPushRegs(); i++)
PopBuilder.addDef(FixedCSRFIMap[i].first, RegState::ImplicitDefine);
PopBuilder.addDef(FixedCSRFIMap[i], RegState::ImplicitDefine);
}
} else {
const char *RestoreLibCall = getRestoreLibCallName(*MF, CSI);
Expand Down