Add symbol, line, and location to DAP disassemble result

The DAP spec allows a number of attributes on the resulting
instructions that gdb currently does not emit.  A user requested some
of these, so this patch adds the 'symbol', 'line', and 'location'
attributes.  While the spec lets the implementation omit 'location' in
some cases, it was simpler in the code to just always emit it, as then
no extra tracking was needed.

1 files changed, 52 insertions, 7 deletions

diff --git a/gdb/python/lib/gdb/dap/disassemble.py b/gdb/python/lib/gdb/dap/disassemble.py
index 65bf3d4..d65790a 100644
--- a/gdb/python/lib/gdb/dap/disassemble.py
+++ b/gdb/python/lib/gdb/dap/disassemble.py
@@ -16,6 +16,50 @@
 import gdb
 
 from .server import capability, request
+from .sources import make_source
+
+
+# This tracks labels associated with a disassembly request and helps
+# with updating individual instructions.
+class _BlockTracker:
+    def __init__(self):
+        # Map from PC to symbol names.  A given PC is assumed to have
+        # just one label -- DAP wouldn't let us return multiple labels
+        # anyway.
+        self.labels = {}
+        # List of blocks that have already been handled.  Note that
+        # blocks aren't hashable so a set is not used.
+        self.blocks = []
+
+    # Add a gdb.Block and its superblocks, ignoring the static and
+    # global block.  BLOCK can also be None, which is ignored.
+    def add_block(self, block):
+        while block is not None:
+            if block.is_static or block.is_global or block in self.blocks:
+                return
+            self.blocks.append(block)
+            if block.function is not None:
+                self.labels[block.start] = block.function.name
+            for sym in block:
+                if sym.addr_class == gdb.SYMBOL_LOC_LABEL:
+                    self.labels[int(sym.value())] = sym.name
+            block = block.superblock
+
+    # Add PC to this tracker.  Update RESULT as appropriate with
+    # information about the source and any label.
+    def add_pc(self, pc, result):
+        self.add_block(gdb.block_for_pc(pc))
+        if pc in self.labels:
+            result["symbol"] = self.labels[pc]
+        sal = gdb.find_pc_line(pc)
+        if sal.symtab is not None:
+            if sal.line != 0:
+                result["line"] = sal.line
+            if sal.symtab.filename is not None:
+                # The spec says this can be omitted in some
+                # situations, but it's a little simpler to just always
+                # supply it.
+                result["location"] = make_source(sal.symtab.filename)
 
 
 @request("disassemble")
@@ -35,17 +79,18 @@ def disassemble(
     except gdb.error:
         # Maybe there was no frame.
         arch = inf.architecture()
+    tracker = _BlockTracker()
     result = []
     total_count = instructionOffset + instructionCount
     for elt in arch.disassemble(pc, count=total_count)[instructionOffset:]:
         mem = inf.read_memory(elt["addr"], elt["length"])
-        result.append(
-            {
-                "address": hex(elt["addr"]),
-                "instruction": elt["asm"],
-                "instructionBytes": mem.hex(),
-            }
-        )
+        insn = {
+            "address": hex(elt["addr"]),
+            "instruction": elt["asm"],
+            "instructionBytes": mem.hex(),
+        }
+        tracker.add_pc(elt["addr"], insn)
+        result.append(insn)
     return {
         "instructions": result,
     }