[lldb] Fix GetExpressionPath for vector registers (#169210)

Vector registers have synthetic values for display purposes. This causes
SBValue::GetExpressionPath to dispatch
to ValueObjectSynthetic instead of ValueObjectRegister, producing
incorrect results.

Fixes #147144

3 files changed, 77 insertions, 0 deletions

diff --git a/lldb/test/API/python_api/exprpath_register/Makefile b/lldb/test/API/python_api/exprpath_register/Makefile
new file mode 100644
index 000000000000..10495940055b
--- /dev/null
+++ b/lldb/test/API/python_api/exprpath_register/Makefile
@@ -0,0 +1,3 @@
+C_SOURCES := main.c
+
+include Makefile.rules
diff --git a/lldb/test/API/python_api/exprpath_register/TestExprPathRegisters.py b/lldb/test/API/python_api/exprpath_register/TestExprPathRegisters.py
new file mode 100644
index 000000000000..4ffbc5e49fb0
--- /dev/null
+++ b/lldb/test/API/python_api/exprpath_register/TestExprPathRegisters.py
@@ -0,0 +1,64 @@
+"""
+Test Getting the expression path for registers works correctly
+"""
+
+import lldb
+from lldbsuite.test import lldbutil
+from lldbsuite.test.lldbtest import TestBase, VALID_BREAKPOINT, VALID_TARGET
+
+
+class TestExprPathRegisters(TestBase):
+    NO_DEBUG_INFO_TESTCASE = True
+
+    def verify_register_path(self, reg_value: lldb.SBValue):
+        stream = lldb.SBStream()
+        reg_name = reg_value.name
+        self.assertTrue(
+            reg_value.GetExpressionPath(stream),
+            f"Expected an expression path for register {reg_name}.",
+        )
+        reg_expr_path = stream.GetData()
+        self.assertEqual(reg_expr_path, f"${reg_name}")
+
+    def test_float_registers(self):
+        """Verify the expression path of the registers is valid."""
+        self.build()
+        _, _, thread, _ = lldbutil.run_to_name_breakpoint(self, "my_foo")
+        frame = thread.GetSelectedFrame()
+        self.assertTrue(frame, "Expected a valid Frame.")
+
+        # possible floating point register on some cpus.
+        register_names = [
+            "xmm0",
+            "ymm0",
+            "v0",
+            "v1",
+            "f0",
+            "f1",
+            "d0",
+            "d1",
+            "vr0",
+            "vr1",
+            "st0",
+            "st1",
+        ]
+        for name in register_names:
+            reg_value = frame.FindRegister(name)
+            # some the register will not be available for the cpu
+            # only verify if it is valid.
+            if reg_value:
+                self.verify_register_path(reg_value)
+
+    def test_all_registers(self):
+        """Test all the registers that is avaiable on the machine"""
+        self.build()
+        _, _, thread, _ = lldbutil.run_to_name_breakpoint(self, "my_foo")
+        frame = thread.GetSelectedFrame()
+        self.assertTrue(frame, "Expected a valid Frame.")
+
+        register_sets = frame.GetRegisters()
+        self.assertTrue(register_sets.IsValid(), "Expected Frame Registers")
+
+        for register_set in register_sets:
+            for register in register_set.children:
+                self.verify_register_path(register)
diff --git a/lldb/test/API/python_api/exprpath_register/main.c b/lldb/test/API/python_api/exprpath_register/main.c
new file mode 100644
index 000000000000..4809a87cdf21
--- /dev/null
+++ b/lldb/test/API/python_api/exprpath_register/main.c
@@ -0,0 +1,10 @@
+
+float my_foo() {
+  float result = 10.0 + 20.0;
+  return result;
+}
+
+int main(void) {
+  float result = my_foo();
+  return (int)result;
+}