[LLDB][DWARF] add tests code from original issue

Author: imkiva

lldb/test/API/lang/rust/enum-variant-same-name/RustEnumValue.py

@@ -0,0 +1,69 @@
+"""Helper library to traverse data emitted for Rust enums """
+from lldbsuite.test.lldbtest import *
+
+DISCRIMINANT_MEMBER_NAME = "$discr$"
+VALUE_MEMBER_NAME = "value"
+
+
+class RustEnumValue:
+    def __init__(self, value: lldb.SBValue):
+        self.value = value
+
+    def getAllVariantTypes(self):
+        result = []
+        for i in range(self._inner().GetNumChildren()):
+            result.append(self.getVariantByIndex(i).GetDisplayTypeName())
+        return result
+
+    def _inner(self) -> lldb.SBValue:
+        return self.value.GetChildAtIndex(0)
+
+    def getVariantByIndex(self, index):
+        return (
+            self._inner()
+            .GetChildAtIndex(index)
+            .GetChildMemberWithName(VALUE_MEMBER_NAME)
+        )
+
+    @staticmethod
+    def _getDiscriminantValueAsUnsigned(discr_sbvalue: lldb.SBValue):
+        byte_size = discr_sbvalue.GetType().GetByteSize()
+        error = lldb.SBError()
+
+        # when discriminant is u16 Clang emits 'unsigned char'
+        # and LLDB seems to treat it as character type disalowing to call GetValueAsUnsigned
+        if byte_size == 1:
+            return discr_sbvalue.GetData().GetUnsignedInt8(error, 0)
+        elif byte_size == 2:
+            return discr_sbvalue.GetData().GetUnsignedInt16(error, 0)
+        elif byte_size == 4:
+            return discr_sbvalue.GetData().GetUnsignedInt32(error, 0)
+        elif byte_size == 8:
+            return discr_sbvalue.GetData().GetUnsignedInt64(error, 0)
+        else:
+            return discr_sbvalue.GetValueAsUnsigned()
+
+    def getCurrentVariantIndex(self):
+        default_index = 0
+        for i in range(self._inner().GetNumChildren()):
+            variant: lldb.SBValue = self._inner().GetChildAtIndex(i)
+            discr = variant.GetChildMemberWithName(DISCRIMINANT_MEMBER_NAME)
+            if discr.IsValid():
+                discr_unsigned_value = RustEnumValue._getDiscriminantValueAsUnsigned(
+                    discr
+                )
+                if variant.GetName() == f"$variant${discr_unsigned_value}":
+                    return discr_unsigned_value
+            else:
+                default_index = i
+        return default_index
+
+    def getFields(self):
+        result = []
+        for i in range(self._inner().GetNumChildren()):
+            type: lldb.SBType = self._inner().GetType()
+            result.append(type.GetFieldAtIndex(i).GetName())
+        return result
+
+    def getCurrentValue(self) -> lldb.SBValue:
+        return self.getVariantByIndex(self.getCurrentVariantIndex())

lldb/test/API/lang/rust/enum-variant-same-name/TestRustEnumVariantSameName.py

@@ -0,0 +1,32 @@
+"""Test that lldb recognizes enum variant emitted by Rust compiler """
+import logging
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from RustEnumValue import RustEnumValue
+
+class TestRustEnumStructs(TestBase):
+    def setUp(self):
+        TestBase.setUp(self)
+        src_dir = self.getSourceDir()
+        yaml_path = os.path.join(src_dir, "main.yaml")
+        obj_path = self.getBuildArtifact("main.o")
+        self.yaml2obj(yaml_path, obj_path)
+        self.dbg.CreateTarget(obj_path)
+
+    def getFromGlobal(self, name):
+        values = self.target().FindGlobalVariables(name, 1)
+        self.assertEqual(values.GetSize(), 1)
+        return RustEnumValue(values[0])
+
+    def test_enum_instance(self):
+        # static ENUM_INSTANCE: A = A::A(B::B(10));
+        value = self.getFromGlobal("ENUM_INSTANCE").getCurrentValue()
+        self.assertEqual(value.GetType().GetDisplayTypeName(), "main::A::A")
+
+        value_b = RustEnumValue(value.GetChildAtIndex(0))
+        self.assertEqual(
+            value_b.getCurrentValue().GetChildAtIndex(0).GetData().GetUnsignedInt8(lldb.SBError(), 0),
+            10
+        )

lldb/test/API/lang/rust/enum-variant-same-name/main.rs

@@ -0,0 +1,15 @@
+/// Command:
+/// rustc -g --emit=obj --crate-type=bin -C panic=abort -C link-arg=-nostdlib main.rs && obj2yaml main.o -o main.yaml
+
+pub enum A {
+    A(B),
+}
+
+pub enum B {
+    B(u8),
+}
+
+static ENUM_INSTANCE: A = A::A(B::B(10));
+
+pub fn main() {
+}