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#pragma once
#include "Gc/DwarfRecords.h"
#include "../Reg.h"
#include "../Operand.h"
#include "Core/Array.h"
namespace code {
namespace dwarf {
STORM_PKG(core.asm.dwarf);
/**
* Generation of DWARF unwinding information to properly support exceptions in the generated
* code. Assumes that DWARF(2) unwinding data is used in the compiler. The eh_frame section
* (which is used during stack unwinding) contains a set of records. Each record is either a
* CIE record or a FDE record. CIE records describe general parameters that can be used from
* multiple FDE records. FDE records describe what happens in a single function.
*
* Note: Examine the file unwind-dw2-fde.h/unwind-dw2-fde.c in the libstdc++ library for
* details on how the exception handling is implemented on GCC. We will abuse some
* structures from there.
*/
class FDEStream;
typedef Nat (*RegToDwarf)(Reg);
typedef Reg (*DwarfToReg)(Nat);
/**
* Generate information about functions, later used by the exception system on some
* platforms.
*/
class FunctionInfo {
STORM_VALUE;
public:
// Create.
FunctionInfo();
// Set the FDE we shall write to, and specify the data alignment of the CIE record.
void set(FDE *fde, Nat codeAlignment, Int dataAlignment, Bool is64, RegToDwarf toDwarf);
// Define CFA offset.
void setCFAOffset(Nat pos, Offset offset);
// Define CFA register.
void setCFARegister(Nat pos, Reg reg);
// Define CFA offset *and* register.
void setCFA(Nat pos, Reg reg, Offset offset);
// Note that a register has been stored to the stack (for preservation).
void preserve(Nat pos, Reg reg, Offset offset);
// Mark the return pointer as being authenticated. This is currently specific to ARM64.
void markReturnAuth(Nat pos);
private:
// The data emitted.
FDE *target;
// Convert register numbers.
UNKNOWN(PTR_NOGC) RegToDwarf regToDwarf;
// Code alignment factor.
Nat codeAlignment;
// Data alignment factor.
Int dataAlignment;
// Use 64-bit offsets?
Bool is64;
// Offset inside 'to'.
Nat offset;
// Last position which we encoded something at.
Nat lastPos;
// Go to 'pos'.
void advance(FDEStream &to, Nat pos);
// Get correct offset.
Int getOffset(Offset offset);
};
// Initialize CIE records for Storm.
// Initialize the CIE records that correspond to what Storm uses. Data alignment is specific
// for backends, so it is provided as a parameter. Returns the current position in the CIE
// record if some backend wishes to continue writing.
// 'returnColumn' is the column where the return address is stored.
Nat initStormCIE(CIE *cie, Nat codeAlignment, Int dataAlignment, Nat returnColumn);
// Parse a FDE record to figure out which registers were preserved.
void findPreservedRegs(Array<Operand> *preservedRegs, Array<Operand> *preservedLocs,
FDE *from, DwarfToReg regs, Int dataAlignment);
}
}
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