dwarflint: Fix reporting of CU x arange mismatch

- report the direction of mismatch correctly
- clarify that we only care about CU DIEs, not any old DIE.  Clarify that
  in a comment in check_debug_info

3 files changed, 7 insertions, 5 deletions

diff --git a/dwarflint/check_debug_aranges.cc b/dwarflint/check_debug_aranges.cc
index 915dcae4..f044b43e 100644
--- a/dwarflint/check_debug_aranges.cc
+++ b/dwarflint/check_debug_aranges.cc
@@ -122,7 +122,7 @@ hole (uint64_t start, uint64_t length, void *user)
       char buf[128];
       where where = WHERE (info.id, NULL);
       char const *what = info.what;
-      char const *cu = "CUs";
+      char const *cu = "CU DIEs";
       if (info.reverse)
 	{
 	  char const *tmp = what;
@@ -158,7 +158,7 @@ compare_coverage (struct elf_file *file,
 		  enum section_id id, char const *what)
 {
   compare_coverage_1 (file, coverage, other, id, what, false);
-  compare_coverage_1 (file, other, coverage, id, what, false);
+  compare_coverage_1 (file, other, coverage, id, what, true);
 }
 
 inline static void
diff --git a/dwarflint/check_debug_info.cc b/dwarflint/check_debug_info.cc
index b64a82eb..32bfd572 100644
--- a/dwarflint/check_debug_info.cc
+++ b/dwarflint/check_debug_info.cc
@@ -943,7 +943,9 @@ namespace
 	    high_pc += low_pc;
 	  }
 
-	/* Check PC coverage.  */
+	/* Check PC coverage.  We do that only for CU DIEs.  Any DIEs
+	   lower in the tree (should) take subset of addresses taken
+	   by the CU DIE.  */
 	if (is_cudie && low_pc != (uint64_t)-1)
 	  {
 	    cu->low_pc = low_pc;
diff --git a/dwarflint/tests/run-aranges_terminate_early.sh b/dwarflint/tests/run-aranges_terminate_early.sh
index 9519f12e..7f695148 100755
--- a/dwarflint/tests/run-aranges_terminate_early.sh
+++ b/dwarflint/tests/run-aranges_terminate_early.sh
@@ -33,10 +33,10 @@ testfiles aranges_terminate_early
 
 testrun_compare ./dwarflint --strict aranges_terminate_early <<EOF
 warning: .debug_aranges: [0x20, 0x30): unnecessary padding with zero bytes.
-warning: .debug_aranges: addresses [0x400474, 0x400481) are covered with CUs, but not with aranges.
+warning: .debug_aranges: addresses [0x400474, 0x400481) are covered with CU DIEs, but not with aranges.
 EOF
 
 testrun_compare ./dwarflint --check=check_debug_aranges --strict aranges_terminate_early <<EOF
 warning: .debug_aranges: [0x20, 0x30): unnecessary padding with zero bytes.
-warning: .debug_aranges: addresses [0x400474, 0x400481) are covered with CUs, but not with aranges.
+warning: .debug_aranges: addresses [0x400474, 0x400481) are covered with CU DIEs, but not with aranges.
 EOF