Simplify _ELFUTILS_PREREQ checking

We were jumping through a few hoops to deal with elfutils < 0.138 that
did not have the _ELFUTILS_PREREQ macro.  I've added an always-false
dummy macro to take its place when it doesn't exit.  All of the other
"#ifdef _ELFUTILS_PREREQ" ugliness can now go away.

5 files changed, 26 insertions, 30 deletions

diff --git a/dwarf_wrappers.h b/dwarf_wrappers.h
index 959ece92..9233fc1d 100644
--- a/dwarf_wrappers.h
+++ b/dwarf_wrappers.h
@@ -8,10 +8,23 @@
 
 #ifndef DWARF_WRAPPERS_H
 #define DWARF_WRAPPERS_H 1
+
+#include "config.h"
+
+extern "C" {
 #include <elfutils/libdw.h>
+#ifdef HAVE_ELFUTILS_VERSION_H
+#include <elfutils/version.h>
+#endif
+}
 
 #include <string>
 
+#if !defined(_ELFUTILS_PREREQ)
+// make a dummy PREREQ check for elfutils < 0.138
+#define _ELFUTILS_PREREQ(major, minor) (0 >= 1)
+#endif
+
 // NB: "rc == 0" means OK in this case
 void dwfl_assert(const std::string& desc, int rc);
 
diff --git a/dwflpp.cxx b/dwflpp.cxx
index 9d0f3f4d..e436a9ca 100644
--- a/dwflpp.cxx
+++ b/dwflpp.cxx
@@ -41,9 +41,6 @@ extern "C" {
 #include <fcntl.h>
 #include <elfutils/libdwfl.h>
 #include <elfutils/libdw.h>
-#ifdef HAVE_ELFUTILS_VERSION_H
-#include <elfutils/version.h>
-#endif
 #include <dwarf.h>
 #include <elf.h>
 #include <obstack.h>
@@ -2593,9 +2590,8 @@ dwflpp::get_cfa_ops (Dwarf_Addr pc)
     clog << "get_cfa_ops @0x" << hex << pc << dec
 	 << ", module_start @0x" << hex << module_start << dec << endl;
 
-#ifdef _ELFUTILS_PREREQ
 #if _ELFUTILS_PREREQ(0,142)
-  // Try debug_frame first, then fall back on eh_frame.             
+  // Try debug_frame first, then fall back on eh_frame.
   size_t cfa_nops;
   Dwarf_Addr bias;
   Dwarf_CFI *cfi = dwfl_module_dwarf_cfi (module, &bias);
@@ -2630,7 +2626,6 @@ dwflpp::get_cfa_ops (Dwarf_Addr pc)
 
     }
 #endif
-#endif
 
   if (sess.verbose > 2)
     clog << (cfa_ops == NULL ? "not " : " ") << "found cfa" << endl;
diff --git a/dwflpp.h b/dwflpp.h
index f6305bcf..b376d004 100644
--- a/dwflpp.h
+++ b/dwflpp.h
@@ -25,19 +25,14 @@
 
 extern "C" {
 #include <elfutils/libdwfl.h>
-#ifdef HAVE_ELFUTILS_VERSION_H
-  #include <elfutils/version.h>
-  #if !_ELFUTILS_PREREQ(0,142)
-    // Always use newer name, old name is deprecated in 0.142.
-    #define elf_getshdrstrndx elf_getshstrndx
-  #endif
-#else
-  // Really old elfutils version, definitely redefine to use old name.
-  #define elf_getshdrstrndx elf_getshstrndx
-#endif
 #include <regex.h>
 }
 
+#if !_ELFUTILS_PREREQ(0,142)
+// Always use newer name, old name is deprecated in 0.142.
+#define elf_getshdrstrndx elf_getshstrndx
+#endif
+
 
 struct func_info;
 struct inline_instance_info;
diff --git a/loc2c-test.c b/loc2c-test.c
index 79cb3296..3c260385 100644
--- a/loc2c-test.c
+++ b/loc2c-test.c
@@ -21,6 +21,11 @@
 #include <stdarg.h>
 #include "loc2c.h"
 
+#if !defined(_ELFUTILS_PREREQ)
+// make a dummy PREREQ check for elfutils < 0.138
+#define _ELFUTILS_PREREQ(major, minor) (0 >= 1)
+#endif
+
 #define _(msg) msg
 
 static void __attribute__ ((noreturn))
@@ -519,7 +524,6 @@ main (int argc, char **argv)
 	{
 	  Dwarf_Op *cfa_ops = NULL;
 
-#ifdef _ELFUTILS_PREREQ
 #if _ELFUTILS_PREREQ(0,142)
 	  size_t cfa_nops;
 	  Dwarf_Addr bias;
@@ -546,7 +550,6 @@ main (int argc, char **argv)
 		}
 	    }
 #endif
-#endif	  
 
 	  handle_variable (scopes, n, out, cubias, &vardie, pc, cfa_ops,
 			   &argv[argi]);
diff --git a/translate.cxx b/translate.cxx
index 1ddc1778..b8e22e49 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -26,9 +26,6 @@
 
 extern "C" {
 #include <elfutils/libdwfl.h>
-#ifdef HAVE_ELFUTILS_VERSION_H
-#include <elfutils/version.h>
-#endif
 }
 
 using namespace std;
@@ -4545,22 +4542,15 @@ dump_unwindsyms (Dwfl_Module *m,
     // Enable workaround for elfutils dwfl bug.
     // see https://bugzilla.redhat.com/show_bug.cgi?id=465872
     // and http://sourceware.org/ml/systemtap/2008-q4/msg00579.html
-#ifdef _ELFUTILS_PREREQ
-  #if _ELFUTILS_PREREQ(0,138)
+#if _ELFUTILS_PREREQ(0,138)
     // Let's standardize to the buggy "end of build-id bits" behavior.
     build_id_vaddr += build_id_len;
-  #endif
-  #if !_ELFUTILS_PREREQ(0,141)
-    #define NEED_ELFUTILS_BUILDID_WORKAROUND
-  #endif
-#else
-  #define NEED_ELFUTILS_BUILDID_WORKAROUND
 #endif
 
     // And check for another workaround needed.
     // see https://bugzilla.redhat.com/show_bug.cgi?id=489439
     // and http://sourceware.org/ml/systemtap/2009-q1/msg00513.html
-#ifdef NEED_ELFUTILS_BUILDID_WORKAROUND
+#if !_ELFUTILS_PREREQ(0,141)
     if (build_id_vaddr < base && dwfl_module_relocations (m) == 1)
       {
         GElf_Addr main_bias;