Make the default triple optional by allowing an empty string

When building LLVM as a (potentially dynamic) library that can be linked against
by multiple compilers, the default triple is not really meaningful.
We allow to explicitely set it to an empty string when configuring LLVM.
In this case, said "target independent" tests in the test suite that are using
the default triple are disabled by matching the newly available feature
"default_triple".

Reviewers: probinson, echristo
Differential Revision: http://reviews.llvm.org/D12660

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 247775

1 files changed, 81 insertions, 0 deletions

diff --git a/llvm/test/DebugInfo/Generic/dead-argument-order.ll b/llvm/test/DebugInfo/Generic/dead-argument-order.ll
new file mode 100644
index 00000000000..b3ae5fe5e31
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/dead-argument-order.ll
@@ -0,0 +1,81 @@
+; REQUIRES: object-emission
+
+; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+
+; Built from the following source with clang -O1
+; struct S { int i; };
+; int function(struct S s, int i) { return s.i + i; }
+
+; Due to the X86_64 ABI, 's' is passed in registers and once optimized, the
+; entirety of 's' is never reconstituted, since only the int is required, and
+; thus the variable's location is unknown/dead to debug info.
+
+; Future/current work should enable us to describe partial variables, which, in
+; this case, happens to be the entire variable.
+
+; CHECK: DW_TAG_subprogram
+; CHECK-NOT: DW_TAG
+; CHECK:   DW_AT_name {{.*}} "function"
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:   DW_TAG_formal_parameter
+; CHECK-NOT: DW_TAG
+; CHECK:     DW_AT_name {{.*}} "s"
+; CHECK-NOT: DW_TAG
+; FIXME: Even though 's' is never reconstituted into a struct, the one member
+; variable is still live and used, and so we should be able to describe 's's
+; location as the location of that int.
+; CHECK-NOT: DW_AT_location
+; CHECK-NOT: {{DW_TAG|NULL}}
+; CHECK:   DW_TAG_formal_parameter
+; CHECK-NOT: DW_TAG
+; CHECK:     DW_AT_location
+; CHECK-NOT: DW_TAG
+; CHECK:     DW_AT_name {{.*}} "i"
+
+
+%struct.S = type { i32 }
+
+; Function Attrs: nounwind readnone uwtable
+define i32 @_Z8function1Si(i32 %s.coerce, i32 %i) #0 {
+entry:
+  tail call void @llvm.dbg.declare(metadata %struct.S* undef, metadata !14, metadata !DIExpression()), !dbg !20
+  tail call void @llvm.dbg.value(metadata i32 %i, i64 0, metadata !15, metadata !DIExpression()), !dbg !20
+  %add = add nsw i32 %i, %s.coerce, !dbg !20
+  ret i32 %add, !dbg !20
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
+
+attributes #0 = { nounwind readnone uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!16, !17}
+!llvm.ident = !{!18}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.5.0 ", isOptimized: true, emissionKind: 1, file: !1, enums: !2, retainedTypes: !3, subprograms: !8, globals: !2, imports: !2)
+!1 = !DIFile(filename: "dead-argument-order.cpp", directory: "/tmp/dbginfo")
+!2 = !{}
+!3 = !{!4}
+!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "S", line: 1, size: 32, align: 32, file: !1, elements: !5, identifier: "_ZTS1S")
+!5 = !{!6}
+!6 = !DIDerivedType(tag: DW_TAG_member, name: "i", line: 1, size: 32, align: 32, file: !1, scope: !"_ZTS1S", baseType: !7)
+!7 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!8 = !{!9}
+!9 = distinct !DISubprogram(name: "function", linkageName: "_Z8function1Si", line: 2, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 2, file: !1, scope: !10, type: !11, function: i32 (i32, i32)* @_Z8function1Si, variables: !13)
+!10 = !DIFile(filename: "dead-argument-order.cpp", directory: "/tmp/dbginfo")
+!11 = !DISubroutineType(types: !12)
+!12 = !{!7, !4, !7}
+!13 = !{!14, !15}
+!14 = !DILocalVariable(name: "s", line: 2, arg: 1, scope: !9, file: !10, type: !"_ZTS1S")
+!15 = !DILocalVariable(name: "i", line: 2, arg: 2, scope: !9, file: !10, type: !7)
+!16 = !{i32 2, !"Dwarf Version", i32 4}
+!17 = !{i32 2, !"Debug Info Version", i32 3}
+!18 = !{!"clang version 3.5.0 "}
+!19 = !{%struct.S* undef}
+!20 = !DILocation(line: 2, scope: !9)
+