Update .debug_line section version information to match DWARF version.

In the past the compiler always emitted .debug_line version 2, though some opcodes from DWARF 3 (e.g. DW_LNS_set_prologue_end, DW_LNS_set_epilogue_begin or DW_LNS_set_isa) and from DWARF 4 could be emitted by the compiler. 

This patch changes version information of .debug_line to exactly match the DWARF version. For .debug_line version 4, a new field maximum_operations_per_instruction is emitted. 

Differential Revision: https://reviews.llvm.org/D16697

llvm-svn: 285355

3 files changed, 43 insertions, 4 deletions

diff --git a/llvm/test/DebugInfo/X86/debug-line-version.s b/llvm/test/DebugInfo/X86/debug-line-version.s
new file mode 100644
index 00000000000..46041097047
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/debug-line-version.s
@@ -0,0 +1,39 @@
+// RUN: llvm-mc -g -dwarf-version 2 -triple  i686-pc-linux-gnu %s -filetype=obj -o - | llvm-dwarfdump - | FileCheck --check-prefix=DWARF2 %s
+// RUN: llvm-mc -g -dwarf-version 3 -triple  i686-pc-linux-gnu %s -filetype=obj -o -  |llvm-dwarfdump - | FileCheck --check-prefix=DWARF3 %s
+// RUN: llvm-mc -g -dwarf-version 4 -triple  i686-pc-linux-gnu %s -filetype=obj -o - | llvm-dwarfdump - | FileCheck  --check-prefix=DWARF4 %s
+
+
+// Check that we generate debug_line version that matches the dwarf version.
+// For DWARF-4, additionally check that maximum_operations_per_instruction
+// field is emitted.
+
+    .text
+    .globl foo
+    .type foo, @function
+    .align 4
+foo:
+    ret
+    .size foo, .-foo
+
+// DWARF2: Compile Unit: length = {{.*}} version = 0x0002
+// DWARF2: Line table prologue:
+// DWARF2-NEXT:    total_length: 0x00000077
+// DWARF2-NEXT:         version: 2
+// DWARF2-NEXT: prologue_length: 0x00000062
+// DWARF2-NOT: max_ops_per_inst: 1
+
+// DWARF3: Compile Unit: length = {{.*}} version = 0x0003
+// DWARF3: Line table prologue:
+// DWARF3-NEXT:    total_length: 0x00000077
+// DWARF3-NEXT:         version: 3
+// DWARF3-NEXT: prologue_length: 0x00000062
+// DWARF3-NOT: max_ops_per_inst: 1
+
+
+// DWARF4: Compile Unit: length = {{.*}} version = 0x0004
+// DWARF4: Line table prologue:
+// DWARF4-NEXT:    total_length: 0x00000078
+// DWARF4-NEXT:         version: 4
+// DWARF4-NEXT: prologue_length: 0x00000063
+// DWARF4: max_ops_per_inst: 1
+
diff --git a/llvm/test/DebugInfo/X86/empty.ll b/llvm/test/DebugInfo/X86/empty.ll
index e156e3bbe5e..6506f5567ad 100644
--- a/llvm/test/DebugInfo/X86/empty.ll
+++ b/llvm/test/DebugInfo/X86/empty.ll
@@ -4,7 +4,7 @@
 ; Expect no line table entry since there are no functions and file references in this compile unit
 ; CHECK: .debug_line contents:
 ; CHECK: Line table prologue:
-; CHECK: total_length: 0x00000019
+; CHECK: total_length: 0x0000001a
 ; CHECK-NOT: file_names[
 
 ; CHECK: .debug_pubnames contents:
diff --git a/llvm/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll b/llvm/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll
index 527f577134c..a60725fe685 100644
--- a/llvm/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll
+++ b/llvm/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll
@@ -15,7 +15,7 @@
 ; CHECK: DW_AT_high_pc [DW_FORM_data4]          (0x00000010)
 
 ; CHECK: DW_TAG_compile_unit
-; CHECK: DW_AT_stmt_list [DW_FORM_sec_offset]   (0x0000003c)
+; CHECK: DW_AT_stmt_list [DW_FORM_sec_offset]   (0x0000003d)
 ; CHECK: DW_AT_low_pc [DW_FORM_addr]            (0x0000000000000010)
 ; CHECK: DW_AT_high_pc [DW_FORM_data4]          (0x00000009)
 ; CHECK: DW_TAG_subprogram
@@ -25,10 +25,10 @@
 
 ; CHECK: .debug_line contents:
 ; CHECK-NEXT: Line table prologue:
-; CHECK-NEXT: total_length: 0x00000038
+; CHECK-NEXT: total_length: 0x00000039
 ; CHECK: file_names[  1]    0 0x00000000 0x00000000 simple.c
 ; CHECK: Line table prologue:
-; CHECK-NEXT: total_length: 0x00000039
+; CHECK-NEXT: total_length: 0x0000003a
 ; CHECK: file_names[  1]    0 0x00000000 0x00000000 simple2.c
 ; CHECK-NOT: file_names