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#include "stdafx.h"
#include "FunctionInfo.h"
#include "Utils/Bitwise.h"
#include "Registers.h"
#include "Stream.h"
#include "Code/PosixEh/Personality.h"
namespace code {
namespace dwarf {
/**
* Initialize CIE records to match the output from FnInfo.
*/
Nat initStormCIE(CIE *cie, Nat codeAlign, Int dataAlign, Nat returnColumn) {
cie->id = 0;
cie->version = 1;
DStream out(cie->data, CIE_DATA);
out.putByte('z'); // There is a size of all augmentation data.
out.putByte('R'); // FDE encoding of addresses.
out.putByte('P'); // Personality function.
out.putByte(0); // End of the string.
out.putUNum(codeAlign); // code alignment
out.putSNum(dataAlign); // data alignment factor
out.putUNum(returnColumn); // location of the return address
out.putUNum(2 + sizeof(void *)); // size of augmentation data
out.putByte(DW_EH_PE_absptr); // absolute addresses
out.putByte(DW_EH_PE_absptr); // encoding of the personality function
out.putPtr(address(&code::eh::stormPersonality));
assert(!out.overflow(), L"Increase CIE_DATA!");
return out.pos;
}
/**
* Emit function information.
*/
FunctionInfo::FunctionInfo() : target(null), codeAlignment(0), dataAlignment(0), offset(0), lastPos(0) {}
void FunctionInfo::set(FDE *fde, Nat code, Int data, Bool is64, RegToDwarf toDwarf) {
this->target = fde;
this->codeAlignment = code;
this->dataAlignment = data;
this->is64 = is64;
this->offset = fde->firstFree();
this->lastPos = 0;
this->regToDwarf = toDwarf;
}
void FunctionInfo::setCFAOffset(Nat pos, Offset offset) {
FDEStream to(target, this->offset);
advance(to, pos);
to.putUOp(DW_CFA_def_cfa_offset, getOffset(offset));
}
void FunctionInfo::setCFARegister(Nat pos, Reg reg) {
FDEStream to(target, this->offset);
advance(to, pos);
to.putUOp(DW_CFA_def_cfa_register, (*regToDwarf)(reg));
}
void FunctionInfo::setCFA(Nat pos, Reg reg, Offset offset) {
FDEStream to(target, this->offset);
advance(to, pos);
to.putUOp(DW_CFA_def_cfa, (*regToDwarf)(reg), getOffset(offset));
}
void FunctionInfo::preserve(Nat pos, Reg reg, Offset offset) {
FDEStream to(target, this->offset);
advance(to, pos);
// Note that we stored the variable.
// Note: These are factored according to the data alignment factor, which we set to -8 above.
Int off = getOffset(offset) / dataAlignment;
assert(off >= 0, L"Offset should be positive, the backend is broken.");
to.putUOp(DW_CFA_offset + (*regToDwarf)(reg), off);
}
void FunctionInfo::markReturnAuth(Nat pos) {
#if defined(ARM_USE_PAC)
FDEStream to(target, this->offset);
advance(to, pos);
to.putOp(DW_CFA_AARCH64_negate_ra_state);
#endif
}
void FunctionInfo::advance(FDEStream &to, Nat pos) {
assert(pos >= lastPos);
if (pos > lastPos) {
assert((pos - lastPos) % codeAlignment == 0);
to.putAdvance((pos - lastPos) / codeAlignment);
lastPos = pos;
}
}
Int FunctionInfo::getOffset(Offset offset) {
if (is64)
return offset.v64();
else
return offset.v32();
}
void findPreservedRegs(Array<Operand> *preservedRegs, Array<Operand> *preservedLocs,
FDE *from, DwarfToReg toReg, Int dataAlignment) {
FDEIStream input(from);
Reg baseRegister = ptrStack;
Int regOffset = abs(dataAlignment);
while (!input.atEnd()) {
Byte op = input.getByte();
if (op >= DW_CFA_restore) {
// We don't handle this one, exit.
break;
} else if (op >= DW_CFA_offset) {
Reg reg = (*toReg)(op & 0x3F);
Int offset = input.getUNum() * dataAlignment;
// Don't bother informing about the frame pointer.
if (!same(reg, ptrFrame)) {
preservedRegs->push(reg);
preservedLocs->push(ptrRel(baseRegister, Offset(offset + regOffset)));
}
} else if (op >= DW_CFA_advance_loc) {
// We can just ignore this byte, the parameter is in the low 6 bits.
} else if (op == DW_CFA_advance_loc1) {
input.getByte();
} else if (op == DW_CFA_advance_loc2) {
input.getByte();
input.getByte();
} else if (op == DW_CFA_advance_loc4) {
input.getByte();
input.getByte();
input.getByte();
input.getByte();
} else if (op == DW_CFA_def_cfa_offset) {
regOffset = input.getUNum(); // The offset.
} else if (op == DW_CFA_def_cfa_register) {
baseRegister = (*toReg)(input.getUNum()); // Register number.
} else if (op == DW_CFA_def_cfa) {
baseRegister = (*toReg)(input.getUNum()); // register
regOffset = input.getUNum(); // offset
} else if (op == DW_CFA_nop) {
// Nothing more to read, just skip to the next one.
} else if (op == DW_CFA_AARCH64_negate_ra_state) {
// Nothhing more to read, just skip to the next one.
} else {
// Unsupported op-code, we just stop.
break;
}
}
}
}
}
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