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Add support for Disassembly Source for GDB #1237

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Add support for Disassembly Source for GDB #1237

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01da087
Add support for Disassembly Source for GDB
WardenGnaw Nov 9, 2021
3d0ae2f
Addressing some PR issues
WardenGnaw Nov 10, 2021
8bebf7e
Addressing PR issues
WardenGnaw Nov 16, 2021
143435d
Show single line source
WardenGnaw Nov 23, 2021
f10e4b6
Handle showing multi-source line code
WardenGnaw Nov 23, 2021
b7870f5
Handle out of order file lines
WardenGnaw Dec 14, 2021
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194 changes: 162 additions & 32 deletions src/MIDebugEngine/AD7.Impl/AD7Disassembly.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,13 +14,20 @@ internal class AD7DisassemblyStream : IDebugDisassemblyStream2
private AD7Engine _engine;
private ulong _addr;
private enum_DISASSEMBLY_STREAM_SCOPE _scope;
private string _pLastDocument;
private uint _dwLastSourceLine;
private bool _lastSourceInfoStale;
private bool _skipNextInstruction;

internal AD7DisassemblyStream(AD7Engine engine, enum_DISASSEMBLY_STREAM_SCOPE scope, IDebugCodeContext2 pCodeContext)
{
_engine = engine;
_scope = scope;
AD7MemoryAddress addr = pCodeContext as AD7MemoryAddress;
_addr = addr.Address;
_pLastDocument = null;
_dwLastSourceLine = 0;
_lastSourceInfoStale = true;
}

#region IDebugDisassemblyStream2 Members
Expand Down Expand Up @@ -89,11 +96,22 @@ private DisassemblyData FetchBadInstruction(enum_DISASSEMBLY_STREAM_FIELDS dwFie
dis.dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_OPCODE;
dis.bstrOpcode = "??";
}

return dis;
}

public int Read(uint dwInstructions, enum_DISASSEMBLY_STREAM_FIELDS dwFields, out uint pdwInstructionsRead, DisassemblyData[] prgDisassembly)
{
if (_lastSourceInfoStale && !_skipNextInstruction)
{
SeekBack(1);
}

if (_skipNextInstruction)
{
dwInstructions += 1;
}

uint iOp = 0;

IEnumerable<DisasmInstruction> instructions = null;
Expand All @@ -106,8 +124,17 @@ public int Read(uint dwInstructions, enum_DISASSEMBLY_STREAM_FIELDS dwFields, ou
// bad address range, return '??'
for (iOp = 0; iOp < dwInstructions; _addr++, ++iOp)
{
if (_skipNextInstruction)
{
_addr++;
dwInstructions--;
_skipNextInstruction = false;
}
prgDisassembly[iOp] = FetchBadInstruction(dwFields);
}
_lastSourceInfoStale = false;
_dwLastSourceLine = 0;
_pLastDocument = null;
pdwInstructionsRead = iOp;
return Constants.S_OK;
}
Expand All @@ -118,52 +145,146 @@ public int Read(uint dwInstructions, enum_DISASSEMBLY_STREAM_FIELDS dwFields, ou
prgDisassembly[iOp] = FetchBadInstruction(dwFields);
}
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@gregg-miskelly gregg-miskelly Nov 17, 2021

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You need a similar change here

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@gregg-miskelly gregg-miskelly Nov 17, 2021

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It seems like we could probably combine the two code paths together.


foreach (DisasmInstruction instruction in instructions)
using (IEnumerator<DisasmInstruction> instructionEnumerator = instructions.GetEnumerator())
{
if (iOp >= dwInstructions)
int idx = 0;
if (_skipNextInstruction)
{
break;
}
_addr = instruction.Addr;
_skipNextInstruction = false;

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_ADDRESS) != 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_ADDRESS;
prgDisassembly[iOp].bstrAddress = instruction.AddressString;
}
instructionEnumerator.MoveNext();
DisasmInstruction instruction = instructionEnumerator.Current;

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_CODELOCATIONID) != 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_CODELOCATIONID;
prgDisassembly[iOp].uCodeLocationId = instruction.Addr;
_dwLastSourceLine = instruction.Line != 0 ? instruction.Line - 1 : 0;
_pLastDocument = instruction.File;

dwInstructions--;
idx++;
}

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_SYMBOL) != 0)
for (; idx < dwInstructions + 1 && iOp < dwInstructions; idx++)
{
if (instruction.Offset == 0)
instructionEnumerator.MoveNext();
DisasmInstruction instruction = instructionEnumerator.Current;

_addr = instruction.Addr;

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_ADDRESS) != 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_SYMBOL;
prgDisassembly[iOp].bstrSymbol = instruction.Symbol ?? string.Empty;
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_ADDRESS;
prgDisassembly[iOp].bstrAddress = instruction.AddressString;
}
}

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_OPCODE) != 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_OPCODE;
prgDisassembly[iOp].bstrOpcode = instruction.Opcode;
}
if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_CODELOCATIONID) != 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_CODELOCATIONID;
prgDisassembly[iOp].uCodeLocationId = instruction.Addr;
}

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_CODEBYTES) != 0)
{
if (!string.IsNullOrWhiteSpace(instruction.CodeBytes))
if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_SYMBOL) != 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_CODEBYTES;
prgDisassembly[iOp].bstrCodeBytes = instruction.CodeBytes;
if (instruction.Offset == 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_SYMBOL;
prgDisassembly[iOp].bstrSymbol = instruction.Symbol ?? string.Empty;
}
}
}

iOp++;
};
if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_OPCODE) != 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_OPCODE;
prgDisassembly[iOp].bstrOpcode = instruction.Opcode;
}

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_CODEBYTES) != 0)
{
if (!string.IsNullOrWhiteSpace(instruction.CodeBytes))
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_CODEBYTES;
prgDisassembly[iOp].bstrCodeBytes = instruction.CodeBytes;
}
}


string currentFile = instruction.File;
uint currentLine = instruction.Line - 1;
bool isNewDocument = string.IsNullOrEmpty(_pLastDocument) || !_pLastDocument.Equals(currentFile, StringComparison.Ordinal);
bool isNewLine = currentLine != _dwLastSourceLine;

/* GDB will return a lines of sources not in sequential order.
* We ignore lines with lower line numbers and have it captured in a different group of source.
*
* Example MI Response:
* src_and_asm_line={line="22",file="main.cpp",fullname="/home/waan/cpp/main.cpp",line_asm_insn=[
* {address="0x00007fc4b52b54c5",func-name="main(int, char**)",offset="124",opcodes="48 8d 95 40 ff ff ff",inst="lea -0xc0(%rbp),%rdx" }
* ]
* },src_and_asm_line={line="21",file="main.cpp",fullname="/home/waan/cpp/main.cpp",line_asm_insn=[
* {address="0x00007fc4b52b54df",func-name="main(int, char**)",offset="150",opcodes="c7 85 48 ff ff ff 02 00 00 00",inst="movl $0x2,-0xb8(%rbp)"}
* ]
* },src_and_asm_line={line="22",file="main.cpp",fullname="/home/waan/cpp/main.cpp",line_asm_insn=[
* {address="0x00007fc4b52b54e9",func-name="main(int, char**)",offset="160",opcodes="48 8d 85 48 ff ff ff",inst="lea -0xb8(%rbp),%rax"}
* }
*/

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_POSITION) != 0 && currentLine != 0 && currentLine >= _dwLastSourceLine)
{
// If we have a new line and the current line is greater than the previously seen source line.
// Try to grab the last seen source line + 1 and show a group of source code.
// Else, just show the single line.
uint startLine = isNewLine && currentLine > _dwLastSourceLine ? _dwLastSourceLine + 1 : currentLine;
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@gregg-miskelly gregg-miskelly Nov 23, 2021

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Suggested change
uint startLine = isNewLine && currentLine > _dwLastSourceLine ? _dwLastSourceLine + 1 : currentLine;
uint startLine = isNewLine && !isNewDocument && currentLine > _dwLastSourceLine ? _dwLastSourceLine + 1 : currentLine;


prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_POSITION;
prgDisassembly[iOp].posBeg = new TEXT_POSITION()
{
dwLine = startLine,
dwColumn = 0
};
prgDisassembly[iOp].posEnd = new TEXT_POSITION()
{
dwLine = currentLine,
dwColumn = 0
};

// Update last seen source line.
_dwLastSourceLine = currentLine;
}

// Show source if we have line and file information and if there is a new line.
if (currentLine != 0 && currentFile != null && isNewLine)
{
prgDisassembly[iOp].dwFlags |= enum_DISASSEMBLY_FLAGS.DF_HASSOURCE;
}

if (!string.IsNullOrWhiteSpace(currentFile))
{
if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_DOCUMENTURL) != 0)
{
// idx 0 is the previous instruction. The first requested instruction
// is at idx 1.
if (isNewDocument || idx == 1)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_DOCUMENTURL;
prgDisassembly[iOp].bstrDocumentUrl = string.Concat("file://", currentFile);
}
}
}

if ((dwFields & enum_DISASSEMBLY_STREAM_FIELDS.DSF_BYTEOFFSET) != 0)
{
prgDisassembly[iOp].dwFields |= enum_DISASSEMBLY_STREAM_FIELDS.DSF_BYTEOFFSET;
// For the disassembly window, offset should be set to 0 to show source and non-zero to hide it.
prgDisassembly[iOp].dwByteOffset = isNewLine ? 0 : uint.MaxValue;
}

if (isNewDocument)
{
prgDisassembly[iOp].dwFlags |= enum_DISASSEMBLY_FLAGS.DF_DOCUMENTCHANGE;
_pLastDocument = instruction.File;
}

iOp++;
}
}

if (iOp < dwInstructions)
{
Expand Down Expand Up @@ -208,6 +329,11 @@ private int SeekForward(long iInstructions)

private int SeekBack(long iInstructions)
{
if (_lastSourceInfoStale)
{
iInstructions += 1;
_skipNextInstruction = true;
}
_engine.DebuggedProcess.WorkerThread.RunOperation(async () =>
{
_addr = await _engine.DebuggedProcess.Disassembly.SeekBack(_addr, (int)iInstructions);
Expand All @@ -217,6 +343,10 @@ private int SeekBack(long iInstructions)

public int Seek(enum_SEEK_START dwSeekStart, IDebugCodeContext2 pCodeContext, ulong uCodeLocationId, long iInstructions)
{
_pLastDocument = null;
_lastSourceInfoStale = true;
_dwLastSourceLine = 0;

if (dwSeekStart == enum_SEEK_START.SEEK_START_CODECONTEXT)
{
AD7MemoryAddress addr = pCodeContext as AD7MemoryAddress;
Expand Down
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