backends: Check type DIE exists before calling dwarf_tag ().

dwarf_attr () or dwarf_form () functions leave typedie NULL when they fail
because of missing attribute or unexpected form. In such cases first check
the DIE exists and return error instead of calling dwarf_tag () and crashing.

This also happens in the testsuite with native tests when elfutils is build
without DWZ support on a distro that uses DWZ DWARF compression on system
libraries. Only the backends used dwarf_tag () directly without checking,
all other uses in elfutils already checked whether the given DIE was NULL.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

13 files changed, 59 insertions, 36 deletions

diff --git a/backends/ChangeLog b/backends/ChangeLog
index ab9cde9c..5fd3b6db 100644
--- a/backends/ChangeLog
+++ b/backends/ChangeLog
@@ -1,3 +1,20 @@
+2013-02-06  Mark Wielaard  <mjw@redhat.com>
+
+	* libebl_CPU.h (DWARF_TAG_OR_RETURN): New macro.
+	* backends/alpha_retval.c (alpha_return_value_location): Use new
+	DWARF_TAG_OR_RETURN macro instead of dwarf_tag ().
+	* backends/arm_retval.c (arm_return_value_location): Likewise.
+	* backends/i386_retval.c (i386_return_value_location): Likewise.
+	* backends/ia64_retval.c (hfa_type): Likewise.
+	(ia64_return_value_location): Likewise.
+	* backends/ppc64_retval.c (ppc64_return_value_location): Likewise.
+	* backends/ppc_retval.c (ppc_return_value_location): Likewise.
+	* backends/s390_retval.c (s390_return_value_location): Likewise.
+	* backends/sh_retval.c (sh_return_value_location): Likewise.
+	* backends/sparc_retval.c (sparc_return_value_location): Likewise.
+	* backends/tilegx_retval.c (tilegx_return_value_location): Likewise.
+	* backends/x86_64_retval.c (x86_64_return_value_location): Likewise.
+
 2013-01-29  Jan Kratochvil  <jan.kratochvil@redhat.com>
 	    Roland McGrath <roland@hack.frob.com>
 
diff --git a/backends/alpha_retval.c b/backends/alpha_retval.c
index 62cbfc7c..6dfa6944 100644
--- a/backends/alpha_retval.c
+++ b/backends/alpha_retval.c
@@ -77,7 +77,7 @@ alpha_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -86,7 +86,7 @@ alpha_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   switch (tag)
@@ -99,7 +99,7 @@ alpha_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
diff --git a/backends/arm_retval.c b/backends/arm_retval.c
index 0c33c5b1..222f7555 100644
--- a/backends/arm_retval.c
+++ b/backends/arm_retval.c
@@ -73,7 +73,7 @@ arm_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -82,7 +82,7 @@ arm_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -96,7 +96,7 @@ arm_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
diff --git a/backends/i386_retval.c b/backends/i386_retval.c
index 95f5b926..90678c32 100644
--- a/backends/i386_retval.c
+++ b/backends/i386_retval.c
@@ -77,7 +77,7 @@ i386_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -86,7 +86,7 @@ i386_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   switch (tag)
@@ -99,7 +99,7 @@ i386_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
diff --git a/backends/ia64_retval.c b/backends/ia64_retval.c
index 644359b4..ac0d8c3d 100644
--- a/backends/ia64_retval.c
+++ b/backends/ia64_retval.c
@@ -109,7 +109,7 @@ hfa_type (Dwarf_Die *typedie, Dwarf_Word size,
       return fpregs_used + nregs;
     }
 
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
   switch (tag)
     {
       Dwarf_Attribute attr_mem;
@@ -248,7 +248,7 @@ ia64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -257,7 +257,7 @@ ia64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -271,7 +271,7 @@ ia64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
diff --git a/backends/libebl_CPU.h b/backends/libebl_CPU.h
index 36b3a4a1..09c8cd10 100644
--- a/backends/libebl_CPU.h
+++ b/backends/libebl_CPU.h
@@ -45,5 +45,11 @@ extern const char *EBLHOOK(init) (Elf *elf, GElf_Half machine,
 
 extern bool (*generic_debugscn_p) (const char *) attribute_hidden;
 
+/* Helper for retval.  Return dwarf_tag (die), but calls return -1
+   if there where previous errors that leave die NULL.  */
+#define DWARF_TAG_OR_RETURN(die)  \
+  ({ Dwarf_Die *_die = (die);	  \
+     if (_die == NULL) return -1; \
+     dwarf_tag (_die); })
 
 #endif	/* libebl_CPU.h */
diff --git a/backends/ppc64_retval.c b/backends/ppc64_retval.c
index b26bb1ee..c5c3b6fe 100644
--- a/backends/ppc64_retval.c
+++ b/backends/ppc64_retval.c
@@ -87,7 +87,7 @@ ppc64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -96,7 +96,7 @@ ppc64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -110,7 +110,7 @@ ppc64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
@@ -181,7 +181,7 @@ ppc64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	      /* Check if it's a character array.  */
 	      attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	      typedie = dwarf_formref_die (attr, &die_mem);
-	      tag = dwarf_tag (typedie);
+	      tag = DWARF_TAG_OR_RETURN (typedie);
 	      if (tag != DW_TAG_base_type)
 		goto aggregate;
 	      if (dwarf_formudata (dwarf_attr_integrate (typedie,
diff --git a/backends/ppc_retval.c b/backends/ppc_retval.c
index 29f5a23d..7ca0c185 100644
--- a/backends/ppc_retval.c
+++ b/backends/ppc_retval.c
@@ -99,7 +99,7 @@ ppc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -108,7 +108,7 @@ ppc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -122,7 +122,7 @@ ppc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
diff --git a/backends/s390_retval.c b/backends/s390_retval.c
index 4cebe456..b671ee86 100644
--- a/backends/s390_retval.c
+++ b/backends/s390_retval.c
@@ -78,7 +78,7 @@ s390_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -87,7 +87,7 @@ s390_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -101,7 +101,7 @@ s390_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
diff --git a/backends/sh_retval.c b/backends/sh_retval.c
index 4692d35c..11662318 100644
--- a/backends/sh_retval.c
+++ b/backends/sh_retval.c
@@ -75,7 +75,7 @@ sh_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -84,7 +84,7 @@ sh_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -98,7 +98,7 @@ sh_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
diff --git a/backends/sparc_retval.c b/backends/sparc_retval.c
index 2c2728c6..dcd37859 100644
--- a/backends/sparc_retval.c
+++ b/backends/sparc_retval.c
@@ -82,7 +82,7 @@ sparc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -91,7 +91,7 @@ sparc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -105,7 +105,7 @@ sparc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
diff --git a/backends/tilegx_retval.c b/backends/tilegx_retval.c
index fd4feef3..e14cc512 100644
--- a/backends/tilegx_retval.c
+++ b/backends/tilegx_retval.c
@@ -69,7 +69,7 @@ tilegx_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -78,7 +78,7 @@ tilegx_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -92,7 +92,7 @@ tilegx_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */
 
@@ -142,7 +142,7 @@ tilegx_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	      /* Check if it's a character array.  */
 	      attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	      typedie = dwarf_formref_die (attr, &die_mem);
-	      tag = dwarf_tag (typedie);
+	      tag = DWARF_TAG_OR_RETURN (typedie);
 	      if (tag != DW_TAG_base_type)
 		goto aggregate;
 	      if (dwarf_formudata (dwarf_attr_integrate (typedie,
diff --git a/backends/x86_64_retval.c b/backends/x86_64_retval.c
index d67b05f9..f3e9f2be 100644
--- a/backends/x86_64_retval.c
+++ b/backends/x86_64_retval.c
@@ -91,7 +91,7 @@ x86_64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 
   Dwarf_Die die_mem;
   Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
-  int tag = dwarf_tag (typedie);
+  int tag = DWARF_TAG_OR_RETURN (typedie);
 
   /* Follow typedefs and qualifiers to get to the actual type.  */
   while (tag == DW_TAG_typedef
@@ -100,7 +100,7 @@ x86_64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
     {
       attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
       typedie = dwarf_formref_die (attr, &die_mem);
-      tag = dwarf_tag (typedie);
+      tag = DWARF_TAG_OR_RETURN (typedie);
     }
 
   Dwarf_Word size;
@@ -114,7 +114,7 @@ x86_64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
 	{
 	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
 	  typedie = dwarf_formref_die (attr, &die_mem);
-	  tag = dwarf_tag (typedie);
+	  tag = DWARF_TAG_OR_RETURN (typedie);
 	}
       /* Fall through.  */