Branch island with numbers #138781
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Branch island with numbers #138781
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forms: '.island2' and '.island.2'. Also add more padding so that we produce an island that takes several jumps.
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@llvm/pr-subscribers-lldb Author: None (jimingham) ChangesReapply the support for stepping through branch islands, add support for a branch that takes multiple hops to get to the target. Full diff: https://github.com/llvm/llvm-project/pull/138781.diff 9 Files Affected:
diff --git a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
index e25c4ff55e408..ad3b63cf59135 100644
--- a/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
+++ b/lldb/source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderDarwin.cpp
@@ -26,6 +26,7 @@
#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"
@@ -923,15 +924,15 @@ 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 (trampoline_name) {
+ if (current_name) {
const ModuleList &images = target_sp->GetImages();
SymbolContextList code_symbols;
- images.FindSymbolsWithNameAndType(trampoline_name, eSymbolTypeCode,
+ images.FindSymbolsWithNameAndType(current_name, eSymbolTypeCode,
code_symbols);
for (const SymbolContext &context : code_symbols) {
Address addr = context.GetFunctionOrSymbolAddress();
@@ -945,8 +946,8 @@ DynamicLoaderDarwin::GetStepThroughTrampolinePlan(Thread &thread,
}
SymbolContextList reexported_symbols;
- images.FindSymbolsWithNameAndType(
- trampoline_name, eSymbolTypeReExported, reexported_symbols);
+ images.FindSymbolsWithNameAndType(current_name, eSymbolTypeReExported,
+ reexported_symbols);
for (const SymbolContext &context : reexported_symbols) {
if (context.symbol) {
Symbol *actual_symbol =
@@ -968,7 +969,7 @@ DynamicLoaderDarwin::GetStepThroughTrampolinePlan(Thread &thread,
}
SymbolContextList indirect_symbols;
- images.FindSymbolsWithNameAndType(trampoline_name, eSymbolTypeResolver,
+ images.FindSymbolsWithNameAndType(current_name, eSymbolTypeResolver,
indirect_symbols);
for (const SymbolContext &context : indirect_symbols) {
@@ -1028,6 +1029,23 @@ 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 plus maybe a .digit suffix.
+ // 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.
+ static const char *g_branch_island_pattern = "\\.island\\.?[0-9]*$";
+ static RegularExpression g_branch_island_regex(g_branch_island_pattern);
+
+ bool is_branch_island = g_branch_island_regex.Execute(current_name);
+ if (!thread_plan_sp && is_branch_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
new file mode 100644
index 0000000000000..062e947f6d6ee
--- /dev/null
+++ b/lldb/test/API/macosx/branch-islands/Makefile
@@ -0,0 +1,16 @@
+C_SOURCES := main.c foo.c
+CFLAGS_EXTRAS := -std=c99
+
+include Makefile.rules
+
+a.out: main.o padding1.o padding2.o padding3.o padding4.o foo.o
+ ${CC} ${LDFLAGS} foo.o padding1.o padding2.o padding3.o padding4.o main.o -o a.out
+
+%.o: $(SRCDIR)/%.s
+ ${CC} -c $<
+
+#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
new file mode 100644
index 0000000000000..b397e0c229b08
--- /dev/null
+++ b/lldb/test/API/macosx/branch-islands/TestBranchIslands.py
@@ -0,0 +1,35 @@
+"""
+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
new file mode 100644
index 0000000000000..a5dd2e59e1d82
--- /dev/null
+++ b/lldb/test/API/macosx/branch-islands/foo.c
@@ -0,0 +1,6 @@
+#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
new file mode 100644
index 0000000000000..b5578bdd715df
--- /dev/null
+++ b/lldb/test/API/macosx/branch-islands/main.c
@@ -0,0 +1,6 @@
+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
new file mode 100644
index 0000000000000..4911e53b0240d
--- /dev/null
+++ b/lldb/test/API/macosx/branch-islands/padding1.s
@@ -0,0 +1,3 @@
+.text
+_padding1:
+.space 120*1024*1024
diff --git a/lldb/test/API/macosx/branch-islands/padding2.s b/lldb/test/API/macosx/branch-islands/padding2.s
new file mode 100644
index 0000000000000..5ad1bad11263b
--- /dev/null
+++ b/lldb/test/API/macosx/branch-islands/padding2.s
@@ -0,0 +1,3 @@
+.text
+_padding2:
+.space 120*1024*1024
diff --git a/lldb/test/API/macosx/branch-islands/padding3.s b/lldb/test/API/macosx/branch-islands/padding3.s
new file mode 100644
index 0000000000000..9f614eecf56d9
--- /dev/null
+++ b/lldb/test/API/macosx/branch-islands/padding3.s
@@ -0,0 +1,3 @@
+.text
+_padding3:
+.space 120*1024*1024
diff --git a/lldb/test/API/macosx/branch-islands/padding4.s b/lldb/test/API/macosx/branch-islands/padding4.s
new file mode 100644
index 0000000000000..12896cf5e5b8e
--- /dev/null
+++ b/lldb/test/API/macosx/branch-islands/padding4.s
@@ -0,0 +1,3 @@
+.text
+_padding4:
+.space 120*1024*1024
|
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
adrian-prantl
approved these changes
May 7, 2025
| // 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. | ||
| static const char *g_branch_island_pattern = "\\.island\\.?[0-9]*$"; |
There was a problem hiding this comment.
This is pedantic, but maybe "\\.island\\(.[0-9]+)?$" would be more precise, since foo.island. with no number should probably not get matched?
| if (!thread_plan_sp && is_branch_island) { | ||
| thread_plan_sp = std::make_shared<ThreadPlanStepInstruction>( | ||
| thread, | ||
| /* step_over= */ false, /* stop_others */ false, eVoteNoOpinion, |
There was a problem hiding this comment.
Suggested change
| /* step_over= */ false, /* stop_others */ false, eVoteNoOpinion, | |
| /*step_over=*/ false, /*stop_others=*/ false, eVoteNoOpinion, |
| %.o: $(SRCDIR)/%.s | ||
| ${CC} -c $< | ||
|
|
||
| #padding1.o: padding1.s |
| @@ -0,0 +1,3 @@ | |||
| .text | |||
There was a problem hiding this comment.
This is the first cross-architecture assembler source file I've seen :-)
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/162/builds/21769 Here is the relevant piece of the build log for the reference |
felipepiovezan
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May 7, 2025
This reverts commit 11f33ab. This is failing on CI.
GeorgeARM
pushed a commit
to GeorgeARM/llvm-project
that referenced
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May 7, 2025
Reapply the support for stepping through branch islands, add support for a branch that takes multiple hops to get to the target.
GeorgeARM
pushed a commit
to GeorgeARM/llvm-project
that referenced
this pull request
May 7, 2025
This reverts commit 11f33ab. This is failing on CI.
jimingham
added a commit
to jimingham/from-apple-llvm-project
that referenced
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May 8, 2025
This reverts commit a123891.
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Reapply the support for stepping through branch islands, add support for a branch that takes multiple hops to get to the target.