[DWARF v5] Reposting r337981, which was reverted in r337997 due to a test failure in debuginfo_tests.

The test failure was caused by the compiler not emitting a __debug_ranges section with DWARF 4 and
earlier when no ranges are needed. The test checks for the existence regardless.

llvm-svn: 338081

3 files changed, 150 insertions, 0 deletions

diff --git a/llvm/test/DebugInfo/X86/cu-ranges.ll b/llvm/test/DebugInfo/X86/cu-ranges.ll
index 271eb1019fa..90911d8ef71 100644
--- a/llvm/test/DebugInfo/X86/cu-ranges.ll
+++ b/llvm/test/DebugInfo/X86/cu-ranges.ll
@@ -5,6 +5,9 @@
 ; RUN: llc -split-dwarf-file=foo.dwo -O0 %s -mtriple=x86_64-unknown-linux-gnu -filetype=obj -o %t
 ; RUN: llvm-dwarfdump -debug-abbrev %t | FileCheck --check-prefix=NO-FUNCTION-SECTIONS %s
 
+; RUN: llc -dwarf-version=5 -O0 %s -mtriple=x86_64-unknown-linux-gnu -filetype=obj -o %t
+; RUN: llvm-dwarfdump -v %t | FileCheck --check-prefix=DWARF5 %s
+
 ; From:
 ; int foo (int a) {
 ;   return a+1;
@@ -24,6 +27,14 @@
 ; NO-FUNCTION-SECTIONS: DW_AT_low_pc DW_FORM_addr
 ; NO-FUNCTION-SECTIONS-NOT: DW_AT_ranges
 
+; For Dwarf 5 check that we neither generate DW_AT_rnglists_base for the CU DIE nor 
+; a .debug_rnglists section. There is only 1 CU range with no scope ranges.
+;
+; DWARF5:     .debug_info contents:
+; DWARF5:     DW_TAG_compile_unit
+; DWARF5-NOT: DW_AT_rnglists_base [DW_FORM_sec_offset]   
+; DWARF5-NOT: .debug_rnglists contents:
+
 ; Function Attrs: nounwind uwtable
 define i32 @foo(i32 %a) #0 !dbg !4 {
 entry:
diff --git a/llvm/test/DebugInfo/X86/rnglists_base_attr.ll b/llvm/test/DebugInfo/X86/rnglists_base_attr.ll
new file mode 100644
index 00000000000..c55626cfd6a
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/rnglists_base_attr.ll
@@ -0,0 +1,89 @@
+; RUN: llc -dwarf-version=5 -O0 %s -mtriple=x86_64-unknown-linux-gnu -filetype=obj -o %t
+; RUN: llvm-dwarfdump -v %t | FileCheck %s
+
+; Make sure we don't generate a duplicate DW_AT_rnglists_base attribute in the CU DIE
+; when more than one range list is emitted.
+; From the source:
+;
+; void f1();
+; void f2() {
+;   f1();
+;   {
+;     bool b;
+;     f1();
+;     f1();
+;   }
+; }
+; __attribute__((section(".text.foo"))) void f3() { }
+ 
+; Compile with clang -gwarf5 -S -emit-llvm
+; and change the resulting IR to move the first call to f1() to between
+; the second and the third call. This, along with the dbg.declare instruction
+; for the variable b, creates a gap in the code range for the nested lexical
+; scope that is b's immediate parent scope. A range list is emitted for that scope.
+;
+; In addition, the placement of f3() in a different section forces a 
+; rangelist to be emitted for the CU instead of simply using low/high pc 
+; attributes.
+
+; CHECK:      .debug_info contents:
+; CHECK:      DW_TAG_compile_unit
+; Make sure we have 2 CU ranges.
+; CHECK:      DW_AT_ranges
+; CHECK-NEXT: [0x{{[0-9a-f]+, 0x[0-9a-f]+}}) ".text"
+; CHECK-NEXT: [0x{{[0-9a-f]+, 0x[0-9a-f]+}}) ".text.foo"
+; We should not see any duplicate DW_AT_rnglists_base attributes.
+; CHECK:      DW_AT_rnglists_base [DW_FORM_sec_offset]                   (0x0000000c)
+; CHECK-NOT:  DW_AT_rnglists_base
+;
+; Make sure we see 2 ranges in the lexical block DIE.
+; CHECK:      DW_TAG_lexical_block
+; CHECK-NOT:  DW_TAG
+; CHECK:      DW_AT_ranges
+; CHECK-NEXT: [0x{{[0-9a-f]+, 0x[0-9a-f]+}}) ".text"
+; CHECK-NEXT: [0x{{[0-9a-f]+, 0x[0-9a-f]+}}) ".text"
+
+define dso_local void @_Z2f2v() !dbg !7 {
+entry:
+  %b = alloca i8, align 1
+  call void @llvm.dbg.declare(metadata i8* %b, metadata !11, metadata !DIExpression()), !dbg !14
+  call void @_Z2f1v(), !dbg !15
+  ; The following call has been moved here from right after the alloca
+  call void @_Z2f1v(), !dbg !10  
+  call void @_Z2f1v(), !dbg !16
+  ret void, !dbg !17
+}
+
+declare dso_local void @_Z2f1v()
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+define dso_local void @_Z2f3v() section ".text.foo" !dbg !18 {
+entry:
+  ret void, !dbg !19
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 7.0.0 (trunk 337837)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "t3.cpp", directory: "/home/test/rangelists", checksumkind: CSK_MD5, checksum: "1ba81b564a832caa8114cd008c199048")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 5}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 7.0.0 (trunk 337837)"}
+!7 = distinct !DISubprogram(name: "f2", linkageName: "_Z2f2v", scope: !1, file: !1, line: 2, type: !8, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{null}
+!10 = !DILocation(line: 3, column: 3, scope: !7)
+!11 = !DILocalVariable(name: "b", scope: !12, file: !1, line: 5, type: !13)
+!12 = distinct !DILexicalBlock(scope: !7, file: !1, line: 4, column: 3)
+!13 = !DIBasicType(name: "bool", size: 8, encoding: DW_ATE_boolean)
+!14 = !DILocation(line: 5, column: 10, scope: !12)
+!15 = !DILocation(line: 6, column: 5, scope: !12)
+!16 = !DILocation(line: 7, column: 5, scope: !12)
+!17 = !DILocation(line: 9, column: 1, scope: !7)
+!18 = distinct !DISubprogram(name: "f3", linkageName: "_Z2f3v", scope: !1, file: !1, line: 10, type: !8, isLocal: false, isDefinition: true, scopeLine: 10, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!19 = !DILocation(line: 10, column: 51, scope: !18)
diff --git a/llvm/test/DebugInfo/X86/rnglists_curanges.ll b/llvm/test/DebugInfo/X86/rnglists_curanges.ll
new file mode 100644
index 00000000000..aac0ef59eee
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/rnglists_curanges.ll
@@ -0,0 +1,50 @@
+; RUN: llc -dwarf-version=5 -O0 %s -mtriple=x86_64-unknown-linux-gnu -filetype=obj -o %t
+; RUN: llvm-dwarfdump -v %t | FileCheck %s
+;
+; Check that we generate DW_AT_rnglists_base in the CU die, as well as a range 
+; list table when we have more than 1 CU range and no scope range.
+;
+; Generated from:
+; 
+; __attribute__((section("text.foo"))) void f1() {}
+; __attribute__((section("text.bar"))) void f2() {}
+;
+; Compile with clangc -gdwarf-5 -O0 -S -emit-llvm
+;
+; CHECK:      .debug_info contents:
+; CHECK:      DW_TAG_compile_unit
+; CHECK-NOT:  DW_TAG
+; CHECK:      DW_AT_rnglists_base [DW_FORM_sec_offset]                   (0x0000000c)
+; CHECK:      .debug_rnglists contents:
+; CHECK:      0x00000000: range list header: length = 0x0000001d, version = 0x0005,
+; CHECK-SAME: addr_size = 0x08, seg_size = 0x00, offset_entry_count = 0x00000000
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local void @f1() section "text.foo" !dbg !7 {
+entry:
+  ret void, !dbg !10
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local void @f2() section "text.bar" !dbg !11 {
+entry:
+  ret void, !dbg !12
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 7.0.0 (trunk 337470)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "test3.c", directory: "/home/test/rangelists", checksumkind: CSK_MD5, checksum: "f3b46bc2e5bc55bdd511ae4ec29577b6")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 5}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 7.0.0 (trunk 337470)"}
+!7 = distinct !DISubprogram(name: "f1", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{null}
+!10 = !DILocation(line: 1, column: 49, scope: !7)
+!11 = distinct !DISubprogram(name: "f2", scope: !1, file: !1, line: 2, type: !8, isLocal: false, isDefinition: true, scopeLine: 2, isOptimized: false, unit: !0, retainedNodes: !2)
+!12 = !DILocation(line: 2, column: 49, scope: !11)