[lldb] Fix source display for artificial locations (#115876)

When retrieving the location of the function declaration, we were
dropping the file component on the floor, which resulted in an amusingly
confusing situation were we displayed the file containing the
implementation of the function, but used the line number of the
declaration. This patch fixes that.

It required a small refactor Function::GetStartLineSourceLineInfo to
return a SupportFile (instead of just the file spec), which in turn
necessitated changes in a couple of other places as well.

lldb/include/lldb/Symbol/Function.h

@@ -457,7 +457,8 @@ public:
   ///
   /// \param[out] line_no
   ///     The line number.
-  void GetStartLineSourceInfo(FileSpec &source_file, uint32_t &line_no);
+  void GetStartLineSourceInfo(lldb::SupportFileSP &source_file_sp,
+                              uint32_t &line_no);
 
   /// Find the file and line number of the source location of the end of the
   /// function.

lldb/source/Breakpoint/BreakpointResolverFileLine.cpp

@@ -139,21 +139,23 @@ void BreakpointResolverFileLine::FilterContexts(SymbolContextList &sc_list) {
     if (!sc.block)
       continue;
 
-    FileSpec file;
+    SupportFileSP file_sp;
     uint32_t line;
     const Block *inline_block = sc.block->GetContainingInlinedBlock();
     if (inline_block) {
       const Declaration &inline_declaration = inline_block->GetInlinedFunctionInfo()->GetDeclaration();
       if (!inline_declaration.IsValid())
         continue;
-      file = inline_declaration.GetFile();
+      file_sp = std::make_shared<SupportFile>(inline_declaration.GetFile());
       line = inline_declaration.GetLine();
     } else if (sc.function)
-      sc.function->GetStartLineSourceInfo(file, line);
+      sc.function->GetStartLineSourceInfo(file_sp, line);
     else
       continue;
 
-    if (file != sc.line_entry.GetFile()) {
+    if (!file_sp ||
+        !file_sp->Equal(*sc.line_entry.file_sp,
+                        SupportFile::eEqualFileSpecAndChecksumIfSet)) {
       LLDB_LOG(log, "unexpected symbol context file {0}",
                sc.line_entry.GetFile());
       continue;
@@ -190,7 +192,8 @@ void BreakpointResolverFileLine::FilterContexts(SymbolContextList &sc_list) {
     const int decl_line_is_too_late_fudge = 1;
     if (line &&
         m_location_spec.GetLine() < line - decl_line_is_too_late_fudge) {
-      LLDB_LOG(log, "removing symbol context at {0}:{1}", file, line);
+      LLDB_LOG(log, "removing symbol context at {0}:{1}",
+               file_sp->GetSpecOnly(), line);
       sc_list.RemoveContextAtIndex(i);
       --i;
     }

lldb/source/Commands/CommandObjectSource.cpp

@@ -784,9 +784,7 @@ protected:
 
       if (sc.block == nullptr) {
         // Not an inlined function
-        FileSpec function_file_spec;
-        sc.function->GetStartLineSourceInfo(function_file_spec, start_line);
-        start_file = std::make_shared<SupportFile>(function_file_spec);
+        sc.function->GetStartLineSourceInfo(start_file, start_line);
         if (start_line == 0) {
           result.AppendErrorWithFormat("Could not find line information for "
                                        "start of function: \"%s\".\n",

lldb/source/Core/Disassembler.cpp

@@ -205,16 +205,20 @@ Disassembler::GetFunctionDeclLineEntry(const SymbolContext &sc) {
     return {};
 
   LineEntry prologue_end_line = sc.line_entry;
-  FileSpec func_decl_file;
+  SupportFileSP func_decl_file_sp;
   uint32_t func_decl_line;
-  sc.function->GetStartLineSourceInfo(func_decl_file, func_decl_line);
+  sc.function->GetStartLineSourceInfo(func_decl_file_sp, func_decl_line);
 
-  if (func_decl_file != prologue_end_line.GetFile() &&
-      func_decl_file != prologue_end_line.original_file_sp->GetSpecOnly())
+  if (!func_decl_file_sp)
+    return {};
+  if (!func_decl_file_sp->Equal(*prologue_end_line.file_sp,
+                                SupportFile::eEqualFileSpecAndChecksumIfSet) &&
+      !func_decl_file_sp->Equal(*prologue_end_line.original_file_sp,
+                                SupportFile::eEqualFileSpecAndChecksumIfSet))
     return {};
 
   SourceLine decl_line;
-  decl_line.file = func_decl_file;
+  decl_line.file = func_decl_file_sp->GetSpecOnly();
   decl_line.line = func_decl_line;
   // TODO: Do we care about column on these entries?  If so, we need to plumb
   // that through GetStartLineSourceInfo.
@@ -410,20 +414,24 @@ void Disassembler::PrintInstructions(Debugger &debugger, const ArchSpec &arch,
                 LineEntry prologue_end_line = sc.line_entry;
                 if (!ElideMixedSourceAndDisassemblyLine(exe_ctx, sc,
                                                         prologue_end_line)) {
-                  FileSpec func_decl_file;
+                  SupportFileSP func_decl_file_sp;
                   uint32_t func_decl_line;
-                  sc.function->GetStartLineSourceInfo(func_decl_file,
+                  sc.function->GetStartLineSourceInfo(func_decl_file_sp,
                                                       func_decl_line);
-                  if (func_decl_file == prologue_end_line.GetFile() ||
-                      func_decl_file ==
-                          prologue_end_line.original_file_sp->GetSpecOnly()) {
+                  if (func_decl_file_sp &&
+                      (func_decl_file_sp->Equal(
+                           *prologue_end_line.file_sp,
+                           SupportFile::eEqualFileSpecAndChecksumIfSet) ||
+                       func_decl_file_sp->Equal(
+                           *prologue_end_line.original_file_sp,
+                           SupportFile::eEqualFileSpecAndChecksumIfSet))) {
                     // Add all the lines between the function declaration and
                     // the first non-prologue source line to the list of lines
                     // to print.
                     for (uint32_t lineno = func_decl_line;
                          lineno <= prologue_end_line.line; lineno++) {
                       SourceLine this_line;
-                      this_line.file = func_decl_file;
+                      this_line.file = func_decl_file_sp->GetSpecOnly();
                       this_line.line = lineno;
                       source_lines_to_display.lines.push_back(this_line);
                     }

lldb/source/Symbol/Function.cpp

@@ -287,10 +287,10 @@ Function::Function(CompileUnit *comp_unit, lldb::user_id_t func_uid,
 
 Function::~Function() = default;
 
-void Function::GetStartLineSourceInfo(FileSpec &source_file,
+void Function::GetStartLineSourceInfo(SupportFileSP &source_file_sp,
                                       uint32_t &line_no) {
   line_no = 0;
-  source_file.Clear();
+  source_file_sp.reset();
 
   if (m_comp_unit == nullptr)
     return;
@@ -299,7 +299,8 @@ void Function::GetStartLineSourceInfo(FileSpec &source_file,
   GetType();
 
   if (m_type != nullptr && m_type->GetDeclaration().GetLine() != 0) {
-    source_file = m_type->GetDeclaration().GetFile();
+    source_file_sp =
+        std::make_shared<SupportFile>(m_type->GetDeclaration().GetFile());
     line_no = m_type->GetDeclaration().GetLine();
   } else {
     LineTable *line_table = m_comp_unit->GetLineTable();
@@ -310,7 +311,7 @@ void Function::GetStartLineSourceInfo(FileSpec &source_file,
     if (line_table->FindLineEntryByAddress(GetAddressRange().GetBaseAddress(),
                                            line_entry, nullptr)) {
       line_no = line_entry.line;
-      source_file = line_entry.GetFile();
+      source_file_sp = line_entry.file_sp;
     }
   }
 }

lldb/source/Target/StackFrame.cpp

@@ -1918,15 +1918,15 @@ bool StackFrame::GetStatus(Stream &strm, bool show_frame_info, bool show_source,
       if (m_sc.comp_unit && m_sc.line_entry.IsValid()) {
         have_debuginfo = true;
         if (source_lines_before > 0 || source_lines_after > 0) {
+          SupportFileSP source_file_sp = m_sc.line_entry.file_sp;
           uint32_t start_line = m_sc.line_entry.line;
           if (!start_line && m_sc.function) {
-            FileSpec source_file;
-            m_sc.function->GetStartLineSourceInfo(source_file, start_line);
+            m_sc.function->GetStartLineSourceInfo(source_file_sp, start_line);
           }
 
           size_t num_lines =
               target->GetSourceManager().DisplaySourceLinesWithLineNumbers(
-                  m_sc.line_entry.file_sp, start_line, m_sc.line_entry.column,
+                  source_file_sp, start_line, m_sc.line_entry.column,
                   source_lines_before, source_lines_after, "->", &strm);
           if (num_lines != 0)
             have_source = true;

lldb/test/API/source-manager/TestSourceManager.py

@@ -314,19 +314,28 @@ class SourceManagerTestCase(TestBase):
         )
 
     def test_artificial_source_location(self):
-        src_file = "artificial_location.c"
-        d = {"C_SOURCES": src_file}
+        src_file = "artificial_location.cpp"
+        d = {"C_SOURCES": "", "CXX_SOURCES": src_file}
         self.build(dictionary=d)
 
-        lldbutil.run_to_source_breakpoint(
-            self, "main", lldb.SBFileSpec(src_file, False)
-        )
+        target = lldbutil.run_to_breakpoint_make_target(self)
+
+        # Find the instruction with line=0 and put a breakpoint there.
+        sc_list = target.FindFunctions("A::foo")
+        self.assertEqual(len(sc_list), 1)
+        insns = sc_list[0].function.GetInstructions(target)
+        insn0 = next(filter(lambda insn: insn.addr.line_entry.line == 0, insns))
+        bkpt = target.BreakpointCreateBySBAddress(insn0.addr)
+        self.assertGreater(bkpt.GetNumLocations(), 0)
+
+        lldbutil.run_to_breakpoint_do_run(self, target, bkpt)
 
         self.expect(
             "process status",
             substrs=[
                 "stop reason = breakpoint",
                 f"{src_file}:0",
+                "static int foo();",
                 "Note: this address is compiler-generated code in function",
                 "that has no source code associated with it.",
             ],

lldb/test/API/source-manager/artificial_location.c

@@ -1,6 +0,0 @@
-int foo() { return 42; }
-
-int main() {
-#line 0
-  return foo();
-}

lldb/test/API/source-manager/artificial_location.cpp

@@ -0,0 +1,8 @@
+#include "artificial_location.h"
+
+int A::foo() {
+#line 0
+  return 42;
+}
+
+int main() { return A::foo(); }

lldb/test/API/source-manager/artificial_location.h

@@ -0,0 +1,3 @@
+struct A {
+  static int foo();
+};