--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/os/aix/vm/porting_aix.cpp	Fri Sep 06 20:16:09 2013 +0200
@@ -0,0 +1,367 @@
+/*
+ * Copyright 2012, 2013 SAP AG. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "asm/assembler.hpp"
+#include "loadlib_aix.hpp"
+#include "porting_aix.hpp"
+#include "utilities/debug.hpp"
+
+#include <demangle.h>
+#include <sys/debug.h>
+
+//////////////////////////////////
+// Provide implementation for dladdr based on LoadedLibraries pool and
+// traceback table scan (see getFuncName).
+
+// Search traceback table in stack,
+// return procedure name from trace back table.
+#define MAX_FUNC_SEARCH_LEN 0x10000
+// Any PC below this value is considered toast.
+#define MINIMUM_VALUE_FOR_PC ((unsigned int*)0x1024)
+
+#define PTRDIFF_BYTES(p1,p2) (((ptrdiff_t)p1) - ((ptrdiff_t)p2))
+
+// Align a pointer without having to cast.
+inline char* align_ptr_up(char* ptr, intptr_t alignment) {
+  return (char*) align_size_up((intptr_t)ptr, alignment);
+}
+
+// Trace if verbose to tty.
+// I use these now instead of the Xtrace system because the latter is
+// not available at init time, hence worthless. Until we fix this, all
+// tracing here is done with -XX:+Verbose.
+#define trcVerbose(fmt, ...) { \
+  if (Verbose) { \
+    fprintf(stderr, fmt, ##__VA_ARGS__); \
+    fputc('\n', stderr); fflush(stderr); \
+  } \
+}
+#define ERRBYE(s) { trcVerbose(s); return -1; }
+
+// Unfortunately, the interface of dladdr makes the implementator
+// responsible for maintaining memory for function name/library
+// name. I guess this is because most OS's keep those values as part
+// of the mapped executable image ready to use. On AIX, this doesn't
+// work, so I have to keep the returned strings. For now, I do this in
+// a primitive string map. Should this turn out to be a performance
+// problem, a better hashmap has to be used.
+class fixed_strings {
+  struct node {
+    char* v;
+    node* next;
+  };
+
+  node* first;
+
+  public:
+
+  fixed_strings() : first(0) {}
+  ~fixed_strings() {
+    node* n = first;
+    while (n) {
+      node* p = n;
+      n = n->next;
+      free(p->v);
+      delete p;
+    }
+  }
+
+  char* intern(const char* s) {
+    for (node* n = first; n; n = n->next) {
+      if (strcmp(n->v, s) == 0) {
+        return n->v;
+      }
+    }
+    node* p = new node;
+    p->v = strdup(s);
+    p->next = first;
+    first = p;
+    return p->v;
+  }
+};
+
+static fixed_strings dladdr_fixed_strings;
+
+// Given a code pointer, returns the function name and the displacement.
+// Function looks for the traceback table at the end of the function.
+extern "C" int getFuncName(
+    codeptr_t pc,                    // [in] program counter
+    char* p_name, size_t namelen,    // [out] optional: function name ("" if not available)
+    int* p_displacement,             // [out] optional: displacement (-1 if not available)
+    const struct tbtable** p_tb,     // [out] optional: ptr to traceback table to get further
+                                     //                 information (NULL if not available)
+    char* p_errmsg, size_t errmsglen // [out] optional: user provided buffer for error messages
+  ) {
+  struct tbtable* tb = 0;
+  unsigned int searchcount = 0;
+
+  // initialize output parameters
+  if (p_name && namelen > 0) {
+    *p_name = '\0';
+  }
+  if (p_errmsg && errmsglen > 0) {
+    *p_errmsg = '\0';
+  }
+  if (p_displacement) {
+    *p_displacement = -1;
+  }
+  if (p_tb) {
+    *p_tb = NULL;
+  }
+
+  // weed out obvious bogus states
+  if (pc < MINIMUM_VALUE_FOR_PC) {
+    ERRBYE("invalid program counter");
+  }
+
+  codeptr_t pc2 = pc;
+
+  // make sure the pointer is word aligned.
+  pc2 = (codeptr_t) align_ptr_up((char*)pc2, 4);
+
+  // Find start of traceback table.
+  // (starts after code, is marked by word-aligned (32bit) zeros)
+  while ((*pc2 != NULL) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) {
+    pc2++;
+  }
+  if (*pc2 != 0) {
+    ERRBYE("could not find traceback table within 5000 bytes of program counter");
+  }
+  //
+  // Set up addressability to the traceback table
+  //
+  tb = (struct tbtable*) (pc2 + 1);
+
+  // Is this really a traceback table? No way to be sure but
+  // some indicators we can check.
+  if (tb->tb.lang >= 0xf && tb->tb.lang <= 0xfb) {
+    // Language specifiers, go from 0 (C) to 14 (Objective C).
+    // According to spec, 0xf-0xfa reserved, 0xfb-0xff reserved for ibm.
+    ERRBYE("not a traceback table");
+  }
+
+  // Existence of fields in the tbtable extension are contingent upon
+  // specific fields in the base table.  Check for their existence so
+  // that we can address the function name if it exists.
+  pc2 = (codeptr_t) tb +
+    sizeof(struct tbtable_short)/sizeof(int);
+  if (tb->tb.fixedparms != 0 || tb->tb.floatparms != 0)
+    pc2++;
+
+  if (tb->tb.has_tboff == TRUE) {
+
+    // I want to know the displacement
+    const unsigned int tb_offset = *pc2;
+    codeptr_t start_of_procedure =
+    (codeptr_t)(((char*)tb) - 4 - tb_offset);  // (-4 to omit leading 0000)
+
+    // Weed out the cases where we did find the wrong traceback table.
+    if (pc < start_of_procedure) {
+      ERRBYE("could not find (the real) traceback table within 5000 bytes of program counter");
+    }
+
+    // return the displacement
+    if (p_displacement) {
+      (*p_displacement) = (int) PTRDIFF_BYTES(pc, start_of_procedure);
+    }
+
+    pc2++;
+  } else {
+    // return -1 for displacement
+    if (p_displacement) {
+      (*p_displacement) = -1;
+    }
+  }
+
+  if (tb->tb.int_hndl == TRUE)
+    pc2++;
+
+  if (tb->tb.has_ctl == TRUE)
+    pc2 += (*pc2) + 1; // don't care
+
+  //
+  // return function name if it exists.
+  //
+  if (p_name && namelen > 0) {
+    if (tb->tb.name_present) {
+      char buf[256];
+      const short l = MIN2<short>(*((short*)pc2), sizeof(buf) - 1);
+      memcpy(buf, (char*)pc2 + sizeof(short), l);
+      buf[l] = '\0';
+
+      p_name[0] = '\0';
+
+      // If it is a C++ name, try and demangle it using the Demangle interface (see demangle.h).
+      char* rest;
+      Name* const name = Demangle(buf, rest);
+      if (name) {
+        const char* const demangled_name = name->Text();
+        if (demangled_name) {
+          strncpy(p_name, demangled_name, namelen-1);
+          p_name[namelen-1] = '\0';
+        }
+        delete name;
+      }
+
+      // Fallback: if demangling did not work, just provide the unmangled name.
+      if (p_name[0] == '\0') {
+        strncpy(p_name, buf, namelen-1);
+        p_name[namelen-1] = '\0';
+      }
+
+    } else {
+      strncpy(p_name, "<nameless function>", namelen-1);
+      p_name[namelen-1] = '\0';
+    }
+  }
+  // Return traceback table, if user wants it.
+  if (p_tb) {
+    (*p_tb) = tb;
+  }
+
+  return 0;
+}
+
+// Special implementation of dladdr for Aix based on LoadedLibraries
+// Note: dladdr returns non-zero for ok, 0 for error!
+// Note: dladdr is not posix, but a non-standard GNU extension. So this tries to
+//   fulfill the contract of dladdr on Linux (see http://linux.die.net/man/3/dladdr)
+// Note: addr may be both an AIX function descriptor or a real code pointer
+//   to the entry of a function.
+extern "C"
+int dladdr(void* addr, Dl_info* info) {
+
+  if (!addr) {
+    return 0;
+  }
+
+  assert(info, "");
+
+  int rc = 0;
+
+  const char* const ZEROSTRING = "";
+
+  // Always return a string, even if a "" one. Linux dladdr manpage
+  // does not say anything about returning NULL
+  info->dli_fname = ZEROSTRING;
+  info->dli_sname = ZEROSTRING;
+  info->dli_saddr = NULL;
+
+  address p = (address) addr;
+  const LoadedLibraryModule* lib = NULL;
+
+  enum { noclue, code, data } type = noclue;
+
+  trcVerbose("dladdr(%p)...", p);
+
+  // Note: input address may be a function. I accept both a pointer to
+  // the entry of a function and a pointer to the function decriptor.
+  // (see ppc64 ABI)
+  lib = LoadedLibraries::find_for_text_address(p);
+  if (lib) {
+    type = code;
+  }
+
+  if (!lib) {
+    // Not a pointer into any text segment. Is it a function descriptor?
+    const FunctionDescriptor* const pfd = (const FunctionDescriptor*) p;
+    p = pfd->entry();
+    if (p) {
+      lib = LoadedLibraries::find_for_text_address(p);
+      if (lib) {
+        type = code;
+      }
+    }
+  }
+
+  if (!lib) {
+    // Neither direct code pointer nor function descriptor. A data ptr?
+    p = (address)addr;
+    lib = LoadedLibraries::find_for_data_address(p);
+    if (lib) {
+      type = data;
+    }
+  }
+
+  // If we did find the shared library this address belongs to (either
+  // code or data segment) resolve library path and, if possible, the
+  // symbol name.
+  if (lib) {
+    const char* const interned_libpath =
+      dladdr_fixed_strings.intern(lib->get_fullpath());
+    if (interned_libpath) {
+      info->dli_fname = interned_libpath;
+    }
+
+    if (type == code) {
+
+      // For code symbols resolve function name and displacement. Use
+      // displacement to calc start of function.
+      char funcname[256] = "";
+      int displacement = 0;
+
+      if (getFuncName((codeptr_t) p, funcname, sizeof(funcname), &displacement,
+                      NULL, NULL, 0) == 0) {
+        if (funcname[0] != '\0') {
+          const char* const interned = dladdr_fixed_strings.intern(funcname);
+          info->dli_sname = interned;
+          trcVerbose("... function name: %s ...", interned);
+        }
+
+        // From the displacement calculate the start of the function.
+        if (displacement != -1) {
+          info->dli_saddr = p - displacement;
+        } else {
+          info->dli_saddr = p;
+        }
+      } else {
+
+        // No traceback table found. Just assume the pointer is it.
+        info->dli_saddr = p;
+
+      }
+
+    } else if (type == data) {
+
+      // For data symbols.
+      info->dli_saddr = p;
+
+    } else {
+      ShouldNotReachHere();
+    }
+
+    rc = 1; // success: return 1 [sic]
+
+  }
+
+  // sanity checks.
+  if (rc) {
+    assert(info->dli_fname, "");
+    assert(info->dli_sname, "");
+    assert(info->dli_saddr, "");
+  }
+
+  return rc; // error: return 0 [sic]
+
+}