diff options
| -rw-r--r-- | std/debug/index.zig | 71 | ||||
| -rw-r--r-- | std/pdb.zig | 12 |
2 files changed, 59 insertions, 24 deletions
diff --git a/std/debug/index.zig b/std/debug/index.zig index 3050d15c59..445f943594 100644 --- a/std/debug/index.zig +++ b/std/debug/index.zig @@ -247,8 +247,7 @@ pub fn writeCurrentStackTraceWindows( start_addr: ?usize, ) !void { var addr_buf: [1024]usize = undefined; - const casted_len = @intCast(u32, addr_buf.len); // TODO shouldn't need this cast - const n = windows.RtlCaptureStackBackTrace(0, casted_len, @ptrCast(**c_void, &addr_buf), null); + const n = windows.RtlCaptureStackBackTrace(0, addr_buf.len, @ptrCast(**c_void, &addr_buf), null); const addrs = addr_buf[0..n]; var start_i: usize = if (start_addr) |saddr| blk: { for (addrs) |addr, i| { @@ -338,50 +337,74 @@ fn printSourceAtAddressWindows(di: *DebugInfo, out_stream: var, relocated_addres switch (subsect_hdr.Kind) { pdb.DebugSubsectionKind.Lines => { - var line_index: usize = sect_offset; + var line_index = sect_offset; const line_hdr = @ptrCast(*pdb.LineFragmentHeader, &subsect_info[line_index]); if (line_hdr.RelocSegment == 0) return error.MissingDebugInfo; line_index += @sizeOf(pdb.LineFragmentHeader); - - const block_hdr = @ptrCast(*pdb.LineBlockFragmentHeader, &subsect_info[line_index]); - line_index += @sizeOf(pdb.LineBlockFragmentHeader); - - const has_column = line_hdr.Flags.LF_HaveColumns; - const frag_vaddr_start = coff_section.header.virtual_address + line_hdr.RelocOffset; const frag_vaddr_end = frag_vaddr_start + line_hdr.CodeSize; - if (relative_address >= frag_vaddr_start and relative_address < frag_vaddr_end) { - var line_i: usize = 0; + + // There is an unknown number of LineBlockFragmentHeaders (and their accompanying line and column records) + // from now on. We will iterate through them, and eventually find a LineInfo that we're interested in, + // breaking out to :subsections. If not, we will make sure to not read anything outside of this subsection. + const subsection_end_index = sect_offset + subsect_hdr.Length; + while (line_index < subsection_end_index) { + const block_hdr = @ptrCast(*pdb.LineBlockFragmentHeader, &subsect_info[line_index]); + line_index += @sizeOf(pdb.LineBlockFragmentHeader); const start_line_index = line_index; - while (line_i < block_hdr.NumLines) : (line_i += 1) { - const line_num_entry = @ptrCast(*pdb.LineNumberEntry, &subsect_info[line_index]); - line_index += @sizeOf(pdb.LineNumberEntry); - const flags = @ptrCast(*pdb.LineNumberEntry.Flags, &line_num_entry.Flags); - const vaddr_start = frag_vaddr_start + line_num_entry.Offset; - const vaddr_end = if (flags.End == 0) frag_vaddr_end else vaddr_start + flags.End; - if (relative_address >= vaddr_start and relative_address < vaddr_end) { + + const has_column = line_hdr.Flags.LF_HaveColumns; + + if (relative_address >= frag_vaddr_start and relative_address < frag_vaddr_end) { + // All line entries are stored inside their line block by ascending start address. + // Heuristic: we want to find the last line entry that has a vaddr_start <= relative_address. + // This is done with a simple linear search. + var line_i: u32 = 0; + while (line_i < block_hdr.NumLines) : (line_i += 1) { + const line_num_entry = @ptrCast(*pdb.LineNumberEntry, &subsect_info[line_index]); + line_index += @sizeOf(pdb.LineNumberEntry); + + const vaddr_start = frag_vaddr_start + line_num_entry.Offset; + if (relative_address <= vaddr_start) { + break; + } + } + + // line_i == 0 would mean that no matching LineNumberEntry was found. + if (line_i > 0) { const subsect_index = checksum_offset + block_hdr.NameIndex; const chksum_hdr = @ptrCast(*pdb.FileChecksumEntryHeader, &mod.subsect_info[subsect_index]); const strtab_offset = @sizeOf(pdb.PDBStringTableHeader) + chksum_hdr.FileNameOffset; try di.pdb.string_table.seekTo(strtab_offset); const source_file_name = try di.pdb.string_table.readNullTermString(allocator); - const line = flags.Start; + + const line_entry_idx = line_i - 1; + const column = if (has_column) blk: { - line_index = start_line_index + @sizeOf(pdb.LineNumberEntry) * block_hdr.NumLines; - line_index += @sizeOf(pdb.ColumnNumberEntry) * line_i; - const col_num_entry = @ptrCast(*pdb.ColumnNumberEntry, &subsect_info[line_index]); + const start_col_index = start_line_index + @sizeOf(pdb.LineNumberEntry) * block_hdr.NumLines; + const col_index = start_col_index + @sizeOf(pdb.ColumnNumberEntry) * line_entry_idx; + const col_num_entry = @ptrCast(*pdb.ColumnNumberEntry, &subsect_info[col_index]); break :blk col_num_entry.StartColumn; } else 0; + + const found_line_index = start_line_index + line_entry_idx * @sizeOf(pdb.LineNumberEntry); + const line_num_entry = @ptrCast(*pdb.LineNumberEntry, &subsect_info[found_line_index]); + const flags = @ptrCast(*pdb.LineNumberEntry.Flags, &line_num_entry.Flags); + break :subsections LineInfo{ .allocator = allocator, .file_name = source_file_name, - .line = line, + .line = flags.Start, .column = column, }; } } - break :subsections null; + } + + // Checking that we are not reading garbage after the (possibly) multiple block fragments. + if (line_index != subsection_end_index) { + return error.InvalidDebugInfo; } }, else => {}, diff --git a/std/pdb.zig b/std/pdb.zig index 0cfc6a6cda..b6e48ad2f7 100644 --- a/std/pdb.zig +++ b/std/pdb.zig @@ -9,6 +9,10 @@ const coff = std.coff; const ArrayList = std.ArrayList; +// Note: most of this is based on information gathered from LLVM source code, +// documentation and/or contributors. + + // https://llvm.org/docs/PDB/DbiStream.html#stream-header pub const DbiStreamHeader = packed struct { VersionSignature: i32, @@ -345,6 +349,10 @@ pub const RecordPrefix = packed struct { RecordKind: SymbolKind, }; +/// The following variable length array appears immediately after the header. +/// The structure definition follows. +/// LineBlockFragmentHeader Blocks[] +/// Each `LineBlockFragmentHeader` as specified below. pub const LineFragmentHeader = packed struct { /// Code offset of line contribution. RelocOffset: u32, @@ -386,7 +394,11 @@ pub const LineNumberEntry = packed struct { /// TODO runtime crash when I make the actual type of Flags this const Flags = packed struct { + /// Start line number Start: u24, + + /// Delta of lines to the end of the expression. Still unclear. + // TODO figure out the point of this field. End: u7, IsStatement: bool, }; |