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GP-902 Modified treatment of ELF Symbols which refer to SHN_UNDEF (0) or

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SHN_ABS (0xfff1) section index values.
This commit is contained in:
ghidra1 2021-04-28 15:46:48 -04:00
parent 74a580191e
commit 0a85fb1984
2 changed files with 59 additions and 29 deletions
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60
Ghidra/Features/Base/src/main/java/ghidra/app/util/opinion/ElfProgramBuilder.java
View File

@ -21,6 +21,8 @@ import java.math.BigInteger;
import java.text.NumberFormat;
import java.util.*;
import org.apache.commons.lang3.StringUtils;
import ghidra.app.cmd.label.SetLabelPrimaryCmd;
import ghidra.app.util.MemoryBlockUtils;
import ghidra.app.util.Option;
@ -40,6 +42,7 @@ import ghidra.program.model.address.*;
import ghidra.program.model.data.*;
import ghidra.program.model.data.Array;
import ghidra.program.model.data.DataUtilities.ClearDataMode;
import ghidra.program.model.lang.Register;
import ghidra.program.model.listing.*;
import ghidra.program.model.mem.*;
import ghidra.program.model.reloc.RelocationTable;
@ -1091,6 +1094,10 @@ class ElfProgramBuilder extends MemorySectionResolver implements ElfLoadHelper {
return program.getLanguage().getDefaultDataSpace();
}
private AddressSpace getConstantSpace() {
return program.getAddressFactory().getConstantSpace();
}
private void allocateUndefinedSymbolData(HashMap<Address, Integer> dataAllocationMap) {
for (Address addr : dataAllocationMap.keySet()) {
// Create undefined data for each data/object symbol
@ -1442,6 +1449,12 @@ class ElfProgramBuilder extends MemorySectionResolver implements ElfLoadHelper {
}
}
else if (sectionIndex == ElfSectionHeaderConstants.SHN_UNDEF) { // Not section relative 0x0000 (e.g., no sections defined)
Address regAddr = findMemoryRegister(elfSymbol);
if (regAddr != null) {
return regAddr;
}
// FIXME: No sections defined or refers to external symbol
// Uncertain what if any offset adjustments should apply, although the
// EXTERNAL block is affected by the program image base
@ -1457,7 +1470,12 @@ class ElfProgramBuilder extends MemorySectionResolver implements ElfLoadHelper {
// TODO: it may be inappropriate to adjust since value may not actually be a memory address - what to do?
// symOffset = loadAdapter.adjustMemoryOffset(symOffset, space);
symbolSpace = getDefaultDataSpace();
Address regAddr = findMemoryRegister(elfSymbol);
if (regAddr != null) {
return regAddr;
}
symbolSpace = getConstantSpace();
}
else if (sectionIndex == ElfSectionHeaderConstants.SHN_COMMON) { // Common symbols - 0xfff2 (
// TODO: Which space ? Can't distinguish data vs. code/default space
@ -1524,6 +1542,33 @@ class ElfProgramBuilder extends MemorySectionResolver implements ElfLoadHelper {
return address;
}
/**
* Find memory register with matching name (ignoring leading and trailing underscore chars).
* @param elfSymbol ELF symbol
* @return register address if found or null
*/
private Address findMemoryRegister(ElfSymbol elfSymbol) {
String name = elfSymbol.getNameAsString();
Address regAddr = getMemoryRegister(name, elfSymbol.getValue());
if (regAddr == null) {
name = StringUtils.stripStart(name, "_");
name = StringUtils.stripEnd(name, "_");
regAddr = getMemoryRegister(name, elfSymbol.getValue());
}
return regAddr;
}
private Address getMemoryRegister(String name, long value) {
Register reg = program.getRegister(name);
if (reg != null && reg.getAddress().isMemoryAddress()) {
Address a = reg.getAddress();
if (value == 0 || value == a.getAddressableWordOffset()) {
return a;
}
}
return null;
}
/**
* Allocate external symbol storage within what will become the EXTERNAL memory block.
@ -1675,6 +1720,19 @@ class ElfProgramBuilder extends MemorySectionResolver implements ElfLoadHelper {
// Remember where in memory Elf symbols have been mapped
setElfSymbolAddress(elfSymbol, address);
if (address.isConstantAddress()) {
// Do not add constant symbols to program symbol table
// define as equate instead
try {
program.getEquateTable()
.createEquate(elfSymbol.getNameAsString(), address.getOffset());
}
catch (DuplicateNameException | InvalidInputException e) {
// ignore
}
return;
}
if (elfSymbol.isSection()) {
// Do not add section symbols to program symbol table
return;

28
Ghidra/Processors/PIC/src/main/java/ghidra/app/util/bin/format/elf/extend/PIC30_ElfExtension.java
View File

@ -22,9 +22,7 @@ import ghidra.app.util.bin.format.elf.*;
import ghidra.program.model.address.Address;
import ghidra.program.model.address.AddressSpace;
import ghidra.program.model.lang.Language;
import ghidra.program.model.lang.Register;
import ghidra.util.exception.CancelledException;
import ghidra.util.exception.NoValueException;
import ghidra.util.task.TaskMonitor;
public class PIC30_ElfExtension extends ElfExtension {
@ -220,32 +218,6 @@ public class PIC30_ElfExtension extends ElfExtension {
Language language = elfLoadHelper.getProgram().getLanguage();
return language.getDefaultDataSpace().equals(start.getAddressSpace().getPhysicalSpace());
}
@Override
public Address calculateSymbolAddress(ElfLoadHelper elfLoadHelper, ElfSymbol elfSymbol)
throws NoValueException {
if (elfSymbol.getValue() != 0 || !elfSymbol.isGlobal() ||
elfSymbol.getSectionHeaderIndex() != 0) {
return null;
}
String name = elfSymbol.getNameAsString();
if (name == null) {
return null;
}
if (name.startsWith("_")) {
name = name.substring(1);
}
Register reg = elfLoadHelper.getProgram().getRegister(name);
if (reg != null && !reg.getAddress().isRegisterAddress()) {
return reg.getAddress(); // only consider memory-based registers
}
return null;
}
@Override
public int getDefaultAlignment(ElfLoadHelper elfLoadHelper) {