Add support for DWARF-4 line number tables.

Reads the maximum_operations_per_instruction field, added in DWARF-4 to the
line number program header.

gold/
	* PR gold/22776
	* dwarf_reader.cc (Sized_dwarf_line_info::read_header_prolog): Add
	support for DWARF-4 line number tables.
	* dwarf_reader.h (Sized_dwarf_line_info::max_ops_per_insn): New field.

diff --git a/gold/ChangeLog b/gold/ChangeLog
index 0ad0db236c1a6ee916955bdedbd179bb97c8cb4e..0df5a7e650192ba873bec5a6008bf52ebd1f03c1 100644 (file)
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,10 @@
+2018-02-02  Cary Coutant  <ccoutant@gmail.com>
+
+       * PR gold/22776
+       * dwarf_reader.cc (Sized_dwarf_line_info::read_header_prolog): Add
+       support for DWARF-4 line number tables.
+       * dwarf_reader.h (Sized_dwarf_line_info::max_ops_per_insn): New field.
+
 2018-01-27  Nick Clifton  <nickc@redhat.com>
 
        This is the 2.30 release:

diff --git a/gold/dwarf_reader.cc b/gold/dwarf_reader.cc
index 63502479ebeebf81fb5b94f361af962fbdcb42a7..5cdb0b2525b5479f19cf295cd18c88da3740cbd0 100644 (file)
--- a/gold/dwarf_reader.cc
+++ b/gold/dwarf_reader.cc
@@ -1667,6 +1667,17 @@ Sized_dwarf_line_info<size, big_endian>::read_header_prolog(
   header_.min_insn_length = *lineptr;
   lineptr += 1;
 
+  if (header_.version < 4)
+    header_.max_ops_per_insn = 1;
+  else
+    {
+      // DWARF 4 added the maximum_operations_per_instruction field.
+      header_.max_ops_per_insn = *lineptr;
+      lineptr += 1;
+      // TODO: Add support for values other than 1.
+      gold_assert(header_.max_ops_per_insn == 1);
+    }
+
   header_.default_is_stmt = *lineptr;
   lineptr += 1;
 

diff --git a/gold/dwarf_reader.h b/gold/dwarf_reader.h
index f994bf2b08e0668484c1a4dec56aea094c507abf..8c969236f1c3c60689adc3fef338bec124f7ea24 100644 (file)
--- a/gold/dwarf_reader.h
+++ b/gold/dwarf_reader.h
@@ -1070,7 +1070,8 @@ class Sized_dwarf_line_info : public Dwarf_line_info
     off_t total_length;
     int version;
     off_t prologue_length;
-    int min_insn_length; // insn stands for instructin
+    int min_insn_length; // insn stands for instruction
+    int max_ops_per_insn; // Added in DWARF-4.
     bool default_is_stmt; // stmt stands for statement
     signed char line_base;
     int line_range;