Revert "Handle step-in over a Darwin "branch island". (#138330)"

[jimingham]

This reverts commit 1ba89ad.

This was failing on the Green Dragon bot, which has an older OS than have on hand, so I'll have to dig up one and see why it's failing there.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: None (jimingham)

Changes

This reverts commit 1ba89ad.

This was failing on the Green Dragon bot, which has an older OS than have on hand, so I'll have to dig up one and see why it's failing there.

---

Full diff: https://github.com/llvm/llvm-project/pull/138569.diff

7 Files Affected:

• (modified) lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp (+7-20)
• (removed) lldb/test/API/macosx/branch-islands/Makefile (-13)
• (removed) lldb/test/API/macosx/branch-islands/TestBranchIslands.py (-35)
• (removed) lldb/test/API/macosx/branch-islands/foo.c (-6)
• (removed) lldb/test/API/macosx/branch-islands/main.c (-6)
• (removed) lldb/test/API/macosx/branch-islands/padding1.s (-3)
• (removed) lldb/test/API/macosx/branch-islands/padding2.s (-3)

diff --git a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
index 52c50cd88902a..e25c4ff55e408 100644
--- a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
+++ b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
@@ -26,7 +26,6 @@
 #include "lldb/Target/Thread.h"
 #include "lldb/Target/ThreadPlanCallFunction.h"
 #include "lldb/Target/ThreadPlanRunToAddress.h"
-#include "lldb/Target/ThreadPlanStepInstruction.h"
 #include "lldb/Utility/DataBuffer.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/LLDBLog.h"
@@ -924,15 +923,15 @@ DynamicLoaderDarwin::GetStepThroughTrampolinePlan(Thread &thread,
   if (current_symbol != nullptr) {
     std::vector<Address> addresses;
 
-    ConstString current_name =
-        current_symbol->GetMangled().GetName(Mangled::ePreferMangled);
     if (current_symbol->IsTrampoline()) {
+      ConstString trampoline_name =
+          current_symbol->GetMangled().GetName(Mangled::ePreferMangled);
 
-      if (current_name) {
+      if (trampoline_name) {
         const ModuleList &images = target_sp->GetImages();
 
         SymbolContextList code_symbols;
-        images.FindSymbolsWithNameAndType(current_name, eSymbolTypeCode,
+        images.FindSymbolsWithNameAndType(trampoline_name, eSymbolTypeCode,
                                           code_symbols);
         for (const SymbolContext &context : code_symbols) {
           Address addr = context.GetFunctionOrSymbolAddress();
@@ -946,8 +945,8 @@ DynamicLoaderDarwin::GetStepThroughTrampolinePlan(Thread &thread,
         }
 
         SymbolContextList reexported_symbols;
-        images.FindSymbolsWithNameAndType(current_name, eSymbolTypeReExported,
-                                          reexported_symbols);
+        images.FindSymbolsWithNameAndType(
+            trampoline_name, eSymbolTypeReExported, reexported_symbols);
         for (const SymbolContext &context : reexported_symbols) {
           if (context.symbol) {
             Symbol *actual_symbol =
@@ -969,7 +968,7 @@ DynamicLoaderDarwin::GetStepThroughTrampolinePlan(Thread &thread,
         }
 
         SymbolContextList indirect_symbols;
-        images.FindSymbolsWithNameAndType(current_name, eSymbolTypeResolver,
+        images.FindSymbolsWithNameAndType(trampoline_name, eSymbolTypeResolver,
                                           indirect_symbols);
 
         for (const SymbolContext &context : indirect_symbols) {
@@ -1029,18 +1028,6 @@ DynamicLoaderDarwin::GetStepThroughTrampolinePlan(Thread &thread,
       thread_plan_sp = std::make_shared<ThreadPlanRunToAddress>(
           thread, load_addrs, stop_others);
     }
-    // One more case we have to consider is "branch islands".  These are regular
-    // TEXT symbols but their names end in .island.  They are to allow arm64
-    // code to branch further than the size of the address slot allows.  We
-    // just need to single-instruction step in that case.
-    if (!thread_plan_sp && current_name.GetStringRef().ends_with(".island")) {
-      thread_plan_sp = std::make_shared<ThreadPlanStepInstruction>(
-          thread,
-          /* step_over= */ false, /* stop_others */ false, eVoteNoOpinion,
-          eVoteNoOpinion);
-      LLDB_LOG(log, "Stepping one instruction over branch island: '{0}'.",
-               current_name);
-    }
   } else {
     LLDB_LOGF(log, "Could not find symbol for step through.");
   }
diff --git a/lldb/test/API/macosx/branch-islands/Makefile b/lldb/test/API/macosx/branch-islands/Makefile
deleted file mode 100644
index 8675bbf6f85de..0000000000000
--- a/lldb/test/API/macosx/branch-islands/Makefile
+++ /dev/null
@@ -1,13 +0,0 @@
-C_SOURCES := main.c foo.c
-CFLAGS_EXTRAS := -std=c99
-
-include Makefile.rules
-
-a.out: main.o padding1.o padding2.o foo.o
-	${CC} ${LDFLAGS} foo.o padding1.o padding2.o main.o -o a.out
-
-padding1.o: padding1.s
-	${CC} -c $(SRCDIR)/padding1.s
-
-padding2.o: padding2.s
-	${CC} -c $(SRCDIR)/padding2.s
diff --git a/lldb/test/API/macosx/branch-islands/TestBranchIslands.py b/lldb/test/API/macosx/branch-islands/TestBranchIslands.py
deleted file mode 100644
index b397e0c229b08..0000000000000
--- a/lldb/test/API/macosx/branch-islands/TestBranchIslands.py
+++ /dev/null
@@ -1,35 +0,0 @@
-"""
-Make sure that we can step in across an arm64 branch island
-"""
-
-
-import lldb
-import lldbsuite.test.lldbutil as lldbutil
-from lldbsuite.test.lldbtest import *
-from lldbsuite.test.decorators import *
-
-
-class TestBranchIslandStepping(TestBase):
-    NO_DEBUG_INFO_TESTCASE = True
-
-    @skipUnlessDarwin
-    def test_step_in_branch_island(self):
-        """Make sure we can step in across a branch island"""
-        self.build()
-        self.main_source_file = lldb.SBFileSpec("main.c")
-        self.do_test()
-
-    def do_test(self):
-        (target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(
-            self, "Set a breakpoint here", self.main_source_file
-        )
-
-        # Make sure that we did manage to generate a branch island for foo:
-        syms = target.FindSymbols("foo.island", lldb.eSymbolTypeCode)
-        self.assertEqual(len(syms), 1, "We did generate an island for foo")
-
-        thread.StepInto()
-        stop_frame = thread.frames[0]
-        self.assertIn("foo", stop_frame.name, "Stepped into foo")
-        var = stop_frame.FindVariable("a_variable_in_foo")
-        self.assertTrue(var.IsValid(), "Found the variable in foo")
diff --git a/lldb/test/API/macosx/branch-islands/foo.c b/lldb/test/API/macosx/branch-islands/foo.c
deleted file mode 100644
index a5dd2e59e1d82..0000000000000
--- a/lldb/test/API/macosx/branch-islands/foo.c
+++ /dev/null
@@ -1,6 +0,0 @@
-#include <stdio.h>
-
-void foo() {
-  int a_variable_in_foo = 10;
-  printf("I am foo: %d.\n", a_variable_in_foo);
-}
diff --git a/lldb/test/API/macosx/branch-islands/main.c b/lldb/test/API/macosx/branch-islands/main.c
deleted file mode 100644
index b5578bdd715df..0000000000000
--- a/lldb/test/API/macosx/branch-islands/main.c
+++ /dev/null
@@ -1,6 +0,0 @@
-extern void foo();
-
-int main() {
-  foo(); // Set a breakpoint here
-  return 0;
-}
diff --git a/lldb/test/API/macosx/branch-islands/padding1.s b/lldb/test/API/macosx/branch-islands/padding1.s
deleted file mode 100644
index e3bdf7007d757..0000000000000
--- a/lldb/test/API/macosx/branch-islands/padding1.s
+++ /dev/null
@@ -1,3 +0,0 @@
-.text
-_junk1:
-.space 120*1024*1024
diff --git a/lldb/test/API/macosx/branch-islands/padding2.s b/lldb/test/API/macosx/branch-islands/padding2.s
deleted file mode 100644
index 187a2c3ebd117..0000000000000
--- a/lldb/test/API/macosx/branch-islands/padding2.s
+++ /dev/null
@@ -1,3 +0,0 @@
-.text
-_junk2:
-.space 120*1024*1024