[lldb][test] Add test for chained PCH debugging

lldb/test/API/lang/cpp/gmodules/pch-chain/Makefile

@@ -0,0 +1,10 @@
+include Makefile.rules
+
+OBJECTS += main.o
+
+$(EXE): $(BUILDDIR)/main.o
+
+$(BUILDDIR)/main.o: main.cpp
+	$(CC) -cc1 -emit-pch -x c++-header -fmodule-format=obj -fmodules -O0 -dwarf-ext-refs -debug-info-kind=standalone $(SRCDIR)/base-pch.h -o base-pch.h.gch
+	$(CC) -cc1 -emit-pch -x c++-header -fmodule-format=obj -fmodules -O0 -dwarf-ext-refs -debug-info-kind=standalone -include-pch base-pch.h.gch $(SRCDIR)/pch.h -o pch.h.gch
+	$(CC) -cc1 -emit-obj -x c++ -fmodules -O0 -dwarf-ext-refs -debug-info-kind=standalone -include-pch pch.h.gch $(SRCDIR)/main.cpp -o $(BUILDDIR)/main.o

lldb/test/API/lang/cpp/gmodules/pch-chain/TestPchChain.py

@@ -0,0 +1,73 @@
+"""
+Tests that we correctly track AST layout info
+(specifically alignment) when moving AST nodes
+between several ClangASTImporter instances
+(in this case, from a pch chain to executable
+to expression AST).
+"""
+
+import lldb
+import os
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestPchChain(TestBase):
+    @add_test_categories(["gmodules"])
+    @expectedFailureAll("Chained pch debugging currently not fully supported")
+    def test_expr(self):
+        self.build()
+        exe = self.getBuildArtifact("a.out")
+        self.target = self.dbg.CreateTarget(exe)
+        self.assertTrue(self.target, VALID_TARGET)
+        lldbutil.run_break_set_by_file_and_line(
+            self, "main.cpp", 9, num_expected_locations=1
+        )
+
+        self.runCmd("run", RUN_SUCCEEDED)
+
+        self.expect(
+            "frame variable data",
+            substrs=["row = 1", "col = 2", "row = 3", "col = 4", "stride = 5"],
+        )
+
+    @add_test_categories(["gmodules"])
+    @expectedFailureAll("Chained pch debugging currently not fully supported")
+    def test_frame_var(self):
+        self.build()
+        exe = self.getBuildArtifact("a.out")
+        self.target = self.dbg.CreateTarget(exe)
+        self.assertTrue(self.target, VALID_TARGET)
+        lldbutil.run_break_set_by_file_and_line(
+            self, "main.cpp", 9, num_expected_locations=1
+        )
+
+        self.runCmd("run", RUN_SUCCEEDED)
+
+        self.expect_expr(
+            "data",
+            result_type="MatrixData",
+            result_children=[
+                ValueCheck(
+                    name="section",
+                    children=[
+                        ValueCheck(
+                            name="origin",
+                            children=[
+                                ValueCheck(name="row", value="1"),
+                                ValueCheck(name="col", value="2"),
+                            ],
+                        ),
+                        ValueCheck(
+                            name="size",
+                            children=[
+                                ValueCheck(name="row", value="3"),
+                                ValueCheck(name="col", value="4"),
+                            ],
+                        ),
+                    ],
+                ),
+                ValueCheck(name="stride", value="5"),
+            ],
+        )

lldb/test/API/lang/cpp/gmodules/pch-chain/base-pch.h

@@ -0,0 +1,9 @@
+#ifndef BASE_PCH_H_IN
+#define BASE_PCH_H_IN
+
+struct [[gnu::aligned(128)]] RowCol {
+  unsigned row;
+  unsigned col;
+};
+
+#endif // _H_IN

lldb/test/API/lang/cpp/gmodules/pch-chain/main.cpp

@@ -0,0 +1,10 @@
+int main(int argc, const char *argv[]) {
+  struct MatrixData data = {0};
+  data.section.origin.row = 1;
+  data.section.origin.col = 2;
+  data.section.size.row = 3;
+  data.section.size.col = 4;
+  data.stride = 5;
+
+  return data.section.size.row;
+}

lldb/test/API/lang/cpp/gmodules/pch-chain/pch.h

@@ -0,0 +1,16 @@
+#ifndef PCH_H_IN
+#define PCH_H_IN
+
+static const int kAlignment = 64;
+
+struct [[gnu::aligned(kAlignment)]] Submatrix {
+  struct RowCol origin;
+  struct RowCol size;
+};
+
+struct [[gnu::aligned(kAlignment)]] MatrixData {
+  struct Submatrix section;
+  unsigned stride;
+};
+
+#endif // _H_IN