[clang] [clang][utils] Remove ClangDataFormat.py for now (PR #96385)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Michael Buch (Michael137)

<details>
<summary>Changes</summary>

This formatter doesn't currently provide much value. It only formats `SourceLocation` and `QualType`. The only formatting it does for `QualType` is call `getAsString()` on it.

The main motivator for the removal however is that the formatter implementation can be very slow (since it uses the expression evaluator in non-trivial ways).

Not infrequently do we get reports about LLDB being slow when debugging Clang, and it turns out the user was loading `ClangDataFormat.py` in their `.lldbinit` by default.

We should eventually develop proper formatters for Clang data-types, but these are currently not ready. So this patch removes them in the meantime to avoid users shooting themselves in the foot, and giving the wrong impression of these being reference implementations.

---
Full diff: https://github.com/llvm/llvm-project/pull/96385.diff


1 Files Affected:

- (removed) clang/utils/ClangDataFormat.py (-170) 


``````````diff
diff --git a/clang/utils/ClangDataFormat.py b/clang/utils/ClangDataFormat.py
deleted file mode 100644
index 28c32a123bdf9..0000000000000
--- a/clang/utils/ClangDataFormat.py
+++ /dev/null
@@ -1,170 +0,0 @@
-"""lldb data formatters for clang classes.
-
-Usage
---
-import this file in your ~/.lldbinit by adding this line:
-
-command script import /path/to/ClangDataFormat.py
-
-After that, instead of getting this:
-
-(lldb) p Tok.Loc
-(clang::SourceLocation) $0 = {
-  (unsigned int) ID = 123582
-}
-
-you'll get:
-
-(lldb) p Tok.Loc
-(clang::SourceLocation) $4 = "/usr/include/i386/_types.h:37:1" (offset: 123582, file, local)
-"""
-
-import lldb
-
-
-def __lldb_init_module(debugger, internal_dict):
-    debugger.HandleCommand(
-        "type summary add -F ClangDataFormat.SourceLocation_summary clang::SourceLocation"
-    )
-    debugger.HandleCommand(
-        "type summary add -F ClangDataFormat.QualType_summary clang::QualType"
-    )
-
-
-def SourceLocation_summary(srcloc, internal_dict):
-    return SourceLocation(srcloc).summary()
-
-
-def QualType_summary(qualty, internal_dict):
-    return QualType(qualty).summary()
-
-
-class SourceLocation(object):
-    def __init__(self, srcloc):
-        self.srcloc = srcloc
-        self.ID = srcloc.GetChildAtIndex(0).GetValueAsUnsigned()
-        self.frame = srcloc.GetFrame()
-
-    def offset(self):
-        return getValueFromExpression(self.srcloc, ".getOffset()").GetValueAsUnsigned()
-
-    def isInvalid(self):
-        return self.ID == 0
-
-    def isMacro(self):
-        return getValueFromExpression(self.srcloc, ".isMacroID()").GetValueAsUnsigned()
-
-    def isLocal(self, srcmgr_path):
-        return self.frame.EvaluateExpression(
-            "(%s).isLocalSourceLocation(%s)"
-            % (srcmgr_path, getExpressionPath(self.srcloc))
-        ).GetValueAsUnsigned()
-
-    def getPrint(self, srcmgr_path):
-        print_str = getValueFromExpression(
-            self.srcloc, ".printToString(%s)" % srcmgr_path
-        )
-        return print_str.GetSummary()
-
-    def summary(self):
-        if self.isInvalid():
-            return "<invalid loc>"
-        srcmgr_path = findObjectExpressionPath("clang::SourceManager", self.frame)
-        if srcmgr_path:
-            return "%s (offset: %d, %s, %s)" % (
-                self.getPrint(srcmgr_path),
-                self.offset(),
-                "macro" if self.isMacro() else "file",
-                "local" if self.isLocal(srcmgr_path) else "loaded",
-            )
-        return "(offset: %d, %s)" % (
-            self.offset(),
-            "macro" if self.isMacro() else "file",
-        )
-
-
-class QualType(object):
-    def __init__(self, qualty):
-        self.qualty = qualty
-
-    def getAsString(self):
-        std_str = getValueFromExpression(self.qualty, ".getAsString()")
-        return std_str.GetSummary()
-
-    def summary(self):
-        desc = self.getAsString()
-        if desc == '"NULL TYPE"':
-            return "<NULL TYPE>"
-        return desc
-
-
-# Key is a (function address, type name) tuple, value is the expression path for
-# an object with such a type name from inside that function.
-FramePathMapCache = {}
-
-
-def findObjectExpressionPath(typename, frame):
-    func_addr = frame.GetFunction().GetStartAddress().GetFileAddress()
-    key = (func_addr, typename)
-    try:
-        return FramePathMapCache[key]
-    except KeyError:
-        # print "CACHE MISS"
-        path = None
-        obj = findObject(typename, frame)
-        if obj:
-            path = getExpressionPath(obj)
-        FramePathMapCache[key] = path
-        return path
-
-
-def findObject(typename, frame):
-    def getTypename(value):
-        # FIXME: lldb should provide something like getBaseType
-        ty = value.GetType()
-        if ty.IsPointerType() or ty.IsReferenceType():
-            return ty.GetPointeeType().GetName()
-        return ty.GetName()
-
-    def searchForType(value, searched):
-        tyname = getTypename(value)
-        # print "SEARCH:", getExpressionPath(value), value.GetType().GetName()
-        if tyname == typename:
-            return value
-        ty = value.GetType()
-        if not (
-            ty.IsPointerType()
-            or ty.IsReferenceType()
-            or
-            # FIXME: lldb should provide something like getCanonicalType
-            tyname.startswith("llvm::IntrusiveRefCntPtr<")
-            or tyname.startswith("llvm::OwningPtr<")
-        ):
-            return None
-        # FIXME: Hashing for SBTypes does not seem to work correctly, uses the typename instead,
-        # and not the canonical one unfortunately.
-        if tyname in searched:
-            return None
-        searched.add(tyname)
-        for i in range(value.GetNumChildren()):
-            child = value.GetChildAtIndex(i, 0, False)
-            found = searchForType(child, searched)
-            if found:
-                return found
-
-    searched = set()
-    value_list = frame.GetVariables(True, True, True, True)
-    for val in value_list:
-        found = searchForType(val, searched)
-        if found:
-            return found if not found.TypeIsPointerType() else found.Dereference()
-
-
-def getValueFromExpression(val, expr):
-    return val.GetFrame().EvaluateExpression(getExpressionPath(val) + expr)
-
-
-def getExpressionPath(val):
-    stream = lldb.SBStream()
-    val.GetExpressionPath(stream)
-    return stream.GetData()

``````````

</details>


https://github.com/llvm/llvm-project/pull/96385