Remove unused code from nativeaot libunwind dependency

src/coreclr/nativeaot/Runtime/CMakeLists.txt

@@ -152,9 +152,6 @@ else()
     include_directories($ENV{EMSCRIPTEN/system/lib/libcxxabi/include})
   endif()
 
-  # Disable building _Unwind_XXX style APIs of libunwind, since we don't use them.
-  add_definitions(-D_LIBUNWIND_DISABLE_ZERO_COST_APIS=1)
-
   # Compile unwinding only for the current compilation target architecture
   add_definitions(-D_LIBUNWIND_IS_NATIVE_ONLY)
 

src/coreclr/nativeaot/Runtime/unix/UnixNativeCodeManager.cpp

@@ -56,7 +56,7 @@ UnixNativeCodeManager::UnixNativeCodeManager(TADDR moduleBase,
       m_pClasslibFunctions(pClasslibFunctions), m_nClasslibFunctions(nClasslibFunctions)
 {
     // Cache the location of unwind sections
-    libunwind::LocalAddressSpace::sThisAddressSpace.findUnwindSections(
+    UnwindHelpers::FindUnwindSections(
         (uintptr_t)pvManagedCodeStartRange, m_UnwindInfoSections);
 }
 

src/coreclr/nativeaot/Runtime/unix/UnwindHelpers.cpp

@@ -62,6 +62,49 @@ using libunwind::UnwindInfoSections;
 
 LocalAddressSpace _addressSpace;
 
+// Debug logging hooks referenced by libunwind's config.h when NDEBUG is not
+// defined. These were previously in libunwind.cpp which is no longer compiled.
+#ifndef NDEBUG
+#include <stdlib.h>
+
+extern "C" {
+
+_LIBUNWIND_HIDDEN
+bool logAPIs() {
+  static bool checked = false;
+  static bool log = false;
+  if (!checked) {
+    log = (getenv("LIBUNWIND_PRINT_APIS") != NULL);
+    checked = true;
+  }
+  return log;
+}
+
+_LIBUNWIND_HIDDEN
+bool logUnwinding() {
+  static bool checked = false;
+  static bool log = false;
+  if (!checked) {
+    log = (getenv("LIBUNWIND_PRINT_UNWINDING") != NULL);
+    checked = true;
+  }
+  return log;
+}
+
+_LIBUNWIND_HIDDEN
+bool logDWARF() {
+  static bool checked = false;
+  static bool log = false;
+  if (!checked) {
+    log = (getenv("LIBUNWIND_PRINT_DWARF") != NULL);
+    checked = true;
+  }
+  return log;
+}
+
+} // extern "C"
+#endif // NDEBUG
+
 #ifdef TARGET_AMD64
 
 // Shim that implements methods required by libunwind over REGDISPLAY
@@ -1396,6 +1439,11 @@ bool UnwindHelpers::GetUnwindProcInfo(PCODE pc, UnwindInfoSections &uwInfoSectio
     return true;
 }
 
+bool UnwindHelpers::FindUnwindSections(uintptr_t pc, UnwindInfoSections &sections)
+{
+    return _addressSpace.findUnwindSections(pc, sections);
+}
+
 #if defined(TARGET_APPLE)
 // Apple considers _dyld_find_unwind_sections to be private API that cannot be used
 // by apps submitted to App Store and TestFlight, both for iOS-like and macOS platforms.

src/coreclr/nativeaot/Runtime/unix/UnwindHelpers.h

@@ -15,4 +15,5 @@ class UnwindHelpers
 public:
     static bool StepFrame(REGDISPLAY *regs, unw_word_t start_ip, uint32_t format, unw_word_t unwind_info);
     static bool GetUnwindProcInfo(PCODE ip, libunwind::UnwindInfoSections &uwInfoSections, unw_proc_info_t *procInfo);
+    static bool FindUnwindSections(uintptr_t pc, libunwind::UnwindInfoSections &sections);
 };

src/native/external/llvm-libunwind.cmake

@@ -6,7 +6,6 @@ endif()
 
 set (LLVM_LIBUNWIND_SOURCES_BASE
     src/Unwind-EHABI.cpp
-    src/libunwind.cpp
 )
 
 set(LLVM_LIBUNWIND_ASM_SOURCES_BASE