8260022: [ppc] os::print_function_and_library_name shall resolve function descriptors transparently

Reviewed-by: mdoerr, lucy

src/hotspot/cpu/ppc/assembler_ppc.hpp

@@ -26,6 +26,7 @@
 #ifndef CPU_PPC_ASSEMBLER_PPC_HPP
 #define CPU_PPC_ASSEMBLER_PPC_HPP
 
+#include "asm/assembler.hpp"
 #include "asm/register.hpp"
 
 // Address is an abstraction used to represent a memory location

src/hotspot/os_cpu/aix_ppc/os_aix_ppc.cpp

@@ -25,6 +25,7 @@
 
 // no precompiled headers
 #include "jvm.h"
+#include "assembler_ppc.hpp"
 #include "asm/assembler.inline.hpp"
 #include "classfile/classLoader.hpp"
 #include "classfile/systemDictionary.hpp"
@@ -493,3 +494,8 @@ bool os::platform_print_native_stack(outputStream* st, void* context, char *buf,
   AixNativeCallstack::print_callstack_for_context(st, (const ucontext_t*)context, true, buf, (size_t) buf_size);
   return true;
 }
+
+// HAVE_FUNCTION_DESCRIPTORS
+void* os::resolve_function_descriptor(void* p) {
+  return ((const FunctionDescriptor*)p)->entry();
+}

src/hotspot/os_cpu/aix_ppc/os_aix_ppc.hpp

@@ -32,8 +32,11 @@
   // Note: Currently only used in 64 bit Windows implementations
   static bool register_code_area(char *low, char *high) { return true; }
 
-#define PLATFORM_PRINT_NATIVE_STACK 1
-static bool platform_print_native_stack(outputStream* st, void* context,
-                                        char *buf, int buf_size);
+  #define PLATFORM_PRINT_NATIVE_STACK 1
+  static bool platform_print_native_stack(outputStream* st, void* context,
+                                          char *buf, int buf_size);
+
+  #define HAVE_FUNCTION_DESCRIPTORS 1
+  static void* resolve_function_descriptor(void* p);
 
 #endif // OS_CPU_AIX_PPC_OS_AIX_PPC_HPP

src/hotspot/os_cpu/linux_ppc/os_linux_ppc.cpp

@@ -25,6 +25,7 @@
 
 // no precompiled headers
 #include "jvm.h"
+#include "assembler_ppc.hpp"
 #include "asm/assembler.inline.hpp"
 #include "classfile/classLoader.hpp"
 #include "classfile/systemDictionary.hpp"
@@ -498,3 +499,9 @@ int os::extra_bang_size_in_bytes() {
   // PPC does not require the additional stack bang.
   return 0;
 }
+
+#ifdef HAVE_FUNCTION_DESCRIPTORS
+void* os::resolve_function_descriptor(void* p) {
+  return ((const FunctionDescriptor*)p)->entry();
+}
+#endif

src/hotspot/os_cpu/linux_ppc/os_linux_ppc.hpp

@@ -32,4 +32,10 @@
   // Note: Currently only used in 64 bit Windows implementations
   static bool register_code_area(char *low, char *high) { return true; }
 
+#if !defined(ABI_ELFv2)
+  // ppc (not ppcle) has function descriptors
+  #define HAVE_FUNCTION_DESCRIPTORS 1
+  static void* resolve_function_descriptor(void* p);
+#endif
+
 #endif // OS_CPU_LINUX_PPC_OS_LINUX_PPC_HPP

src/hotspot/share/runtime/os.cpp

@@ -898,8 +898,24 @@ bool os::print_function_and_library_name(outputStream* st,
     buflen = O_BUFLEN;
   }
   int offset = 0;
-  const bool have_function_name = dll_address_to_function_name(addr, p, buflen,
-                                                               &offset, demangle);
+  bool have_function_name = dll_address_to_function_name(addr, p, buflen,
+                                                         &offset, demangle);
+  bool is_function_descriptor = false;
+#ifdef HAVE_FUNCTION_DESCRIPTORS
+  // When we deal with a function descriptor instead of a real code pointer, try to
+  // resolve it. There is a small chance that a random pointer given to this function
+  // may just happen to look like a valid descriptor, but this is rare and worth the
+  // risk to see resolved function names. But we will print a little suffix to mark
+  // this as a function descriptor for the reader (see below).
+  if (!have_function_name && os::is_readable_pointer(addr)) {
+    address addr2 = (address)os::resolve_function_descriptor(addr);
+    if (have_function_name = is_function_descriptor =
+        dll_address_to_function_name(addr2, p, buflen, &offset, demangle)) {
+      addr = addr2;
+    }
+  }
+#endif // HANDLE_FUNCTION_DESCRIPTORS
+
   if (have_function_name) {
     // Print function name, optionally demangled
     if (demangle && strip_arguments) {
@@ -934,6 +950,12 @@ bool os::print_function_and_library_name(outputStream* st,
       st->print("+%d", offset);
     }
   }
+
+  // Write a trailing marker if this was a function descriptor
+  if (have_function_name && is_function_descriptor) {
+    st->print_raw(" (FD)");
+  }
+
   return have_function_name || have_library_name;
 }