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BitFields - corrected DWARF bitfield parse and incorporated use of

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DW_AT_byte_size
This commit is contained in:
ghidra1 2019-07-11 14:03:13 -04:00
parent 5c19a5c124
commit 27e8356316
1 changed files with 31 additions and 24 deletions
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55
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf4/next/DWARFDataTypeImporter.java
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@ -780,8 +780,11 @@ public class DWARFDataTypeImporter {
childDT = new DWARFDataType(copiedType, null, childDT.offsets);
}
boolean hasMemberOffset =
childDIEA.hasAttribute(DWARFAttribute.DW_AT_data_member_location);
int memberOffset = 0;
if (childDIEA.hasAttribute(DWARFAttribute.DW_AT_data_member_location)) {
if (hasMemberOffset) {
try {
memberOffset = childDIEA.parseDataMemberOffset(
DWARFAttribute.DW_AT_data_member_location, 0);
@ -825,47 +828,51 @@ public class DWARFDataTypeImporter {
DWARFUtil.appendDescription(structure,
memberDesc("Missing member",
"Bad data type for bitfield: " + childDT.dataType.getName(), memberName,
childDT, -1, -1, bitSize),
childDT, -1, bitSize, -1),
"\n");
continue;
}
int dtBitLen = dtLen * 8;
int containerLen;
if (hasMemberOffset) {
int byteSize = childDIEA.parseInt(DWARFAttribute.DW_AT_byte_size, -1);
containerLen = byteSize <= 0 ? dtLen : byteSize;
}
else {
containerLen = structure.getLength();
}
int containerBitLen = containerLen * 8;
int bitOffset = childDIEA.parseInt(DWARFAttribute.DW_AT_data_bit_offset, -1);
int ghidraBitOffset;
if (bitOffset == -1) {
// try to fall back to previous dwarf version's bit_offset attribute that has slightly different info
bitOffset = childDIEA.parseInt(DWARFAttribute.DW_AT_bit_offset, -1);
if (bitOffset != -1) {
// convert DWARF bit offset value to Ghidra bit offset
bitOffset = dtBitLen - bitOffset - bitSize;
}
if (bitOffset < 0 || bitOffset > dtBitLen) {
DWARFUtil.appendDescription(structure, memberDesc("Missing member",
"bad bitOffset", memberName, childDT, memberOffset, bitOffset, bitSize),
"\n");
continue;
}
// convert DWARF bit offset value to Ghidra bit offset
ghidraBitOffset = containerBitLen - bitOffset - bitSize;
}
else {
// convert DWARF bit offset to Ghidra bit offset
bitOffset = bitOffset - (memberOffset * 8);
ghidraBitOffset = bitOffset - (memberOffset * 8);
boolean isBE = prog.getGhidraProgram().getMemory().isBigEndian();
if (isBE) {
bitOffset = dtBitLen - bitOffset - bitSize;
}
if (bitOffset < 0 || bitOffset > dtBitLen) {
DWARFUtil.appendDescription(structure, memberDesc("Missing member",
"bad bitOffset", memberName, childDT, memberOffset, bitOffset, bitSize),
"\n");
continue;
ghidraBitOffset = containerBitLen - ghidraBitOffset - bitSize;
}
}
if (bitOffset < 0 || ghidraBitOffset < 0 || ghidraBitOffset >= containerBitLen) {
DWARFUtil.appendDescription(structure, memberDesc("Missing member",
"bad bitOffset", memberName, childDT, memberOffset, bitSize, bitOffset),
"\n");
continue;
}
try {
// TODO: need safety checks here to make sure that using insertAt() doesn't
// modify the struct
structure.insertBitFieldAt(memberOffset, dtLen, bitOffset, childDT.dataType,
bitSize, memberName, null);
structure.insertBitFieldAt(memberOffset, containerLen, ghidraBitOffset,
childDT.dataType, bitSize, memberName, null);
}
catch (InvalidDataTypeException e) {
Msg.error(this,
@ -874,7 +881,7 @@ public class DWARFDataTypeImporter {
"], skipping: " + e.getMessage());
DWARFUtil.appendDescription(structure,
memberDesc("Missing member ", "Failed to add bitfield", memberName, childDT,
memberOffset, bitOffset, bitSize),
memberOffset, bitSize, bitOffset),
"\n");
}
}