[safestack] Fixup llvm.dbg.value when rewriting unsafe allocas.

When moving unsafe allocas to the unsafe stack, dbg.declare intrinsics are
updated to refer to the new location.

This change does the same to dbg.value intrinsics.

llvm-svn: 272968
diff --git a/llvm/test/Transforms/SafeStack/debug-loc-dynamic.ll b/llvm/test/Transforms/SafeStack/debug-loc-dynamic.ll
new file mode 100644
index 0000000..280d010
--- /dev/null
+++ b/llvm/test/Transforms/SafeStack/debug-loc-dynamic.ll
@@ -0,0 +1,57 @@
+; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
+
+; Test llvm.dbg.value for dynamic allocas moved onto the unsafe stack.
+; In the dynamic alloca case, the dbg.value does not change with the exception
+; of the alloca pointer in the first argument being replaced with the new stack
+; top address.
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @f(i32 %n) safestack !dbg !6 {
+entry:
+  tail call void @llvm.dbg.value(metadata i32 %n, i64 0, metadata !11, metadata !14), !dbg !15
+  %0 = zext i32 %n to i64, !dbg !16
+
+; CHECK:  store i8* %[[VLA:.*]], i8** @__safestack_unsafe_stack_ptr
+; CHECK:  tail call void @llvm.dbg.value(metadata i8* %[[VLA]], i64 0, metadata ![[TYPE:.*]], metadata ![[EXPR:.*]])
+; CHECK:  call void @capture({{.*}} %[[VLA]])
+
+  %vla = alloca i8, i64 %0, align 16, !dbg !16
+  tail call void @llvm.dbg.value(metadata i8* %vla, i64 0, metadata !12, metadata !17), !dbg !18
+  call void @capture(i8* nonnull %vla), !dbg !19
+  ret void, !dbg !20
+}
+
+declare void @capture(i8*)
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 272832) (llvm/trunk 272831)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "../llvm/1.cc", directory: "/code/build-llvm")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{!"clang version 3.9.0 (trunk 272832) (llvm/trunk 272831)"}
+!6 = distinct !DISubprogram(name: "f", linkageName: "_Z1fi", scope: !1, file: !1, line: 2, type: !7, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !10)
+!7 = !DISubroutineType(types: !8)
+!8 = !{null, !9}
+!9 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!10 = !{!11, !12}
+!11 = !DILocalVariable(name: "n", arg: 1, scope: !6, file: !1, line: 2, type: !9)
+
+; CHECK-DAG: ![[TYPE]] = !DILocalVariable(name: "x",
+!12 = !DILocalVariable(name: "x", scope: !6, file: !1, line: 3, type: !13)
+!13 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
+!14 = !DIExpression()
+!15 = !DILocation(line: 2, column: 12, scope: !6)
+!16 = !DILocation(line: 3, column: 3, scope: !6)
+
+; CHECK-DAG: ![[EXPR]] = !DIExpression(DW_OP_deref)
+!17 = !DIExpression(DW_OP_deref)
+!18 = !DILocation(line: 3, column: 8, scope: !6)
+!19 = !DILocation(line: 4, column: 3, scope: !6)
+!20 = !DILocation(line: 5, column: 1, scope: !6)
diff --git a/llvm/test/Transforms/SafeStack/debug-loc2.ll b/llvm/test/Transforms/SafeStack/debug-loc2.ll
new file mode 100644
index 0000000..35e9b77
--- /dev/null
+++ b/llvm/test/Transforms/SafeStack/debug-loc2.ll
@@ -0,0 +1,98 @@
+; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
+
+; Test llvm.dbg.value for the local variables moved onto the unsafe stack.
+; SafeStack rewrites them relative to the unsafe stack pointer (base address of
+; the unsafe stack frame).
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline safestack uwtable
+define void @f() #0 !dbg !6 {
+entry:
+; CHECK:   %[[USP:.*]] = load i8*, i8** @__safestack_unsafe_stack_ptr
+  %x1 = alloca i32, align 4
+  %x2 = alloca i32, align 4
+  %0 = bitcast i32* %x1 to i8*, !dbg !13
+  %1 = bitcast i32* %x2 to i8*, !dbg !14
+
+; Unhandled dbg.value: expression does not start with OP_DW_deref
+; CHECK: call void @llvm.dbg.value(metadata ![[EMPTY:.*]], i64 0, metadata !{{.*}}, metadata !{{.*}})
+  tail call void @llvm.dbg.value(metadata i32* %x1, i64 0, metadata !10, metadata !23), !dbg !16
+
+; Unhandled dbg.value: expression does not start with OP_DW_deref
+; CHECK: call void @llvm.dbg.value(metadata ![[EMPTY]], i64 0, metadata !{{.*}}, metadata !{{.*}})
+  tail call void @llvm.dbg.value(metadata i32* %x1, i64 0, metadata !10, metadata !24), !dbg !16
+
+; Supported dbg.value: rewritted based on the [[USP]] value.
+; CHECK: call void @llvm.dbg.value(metadata i8* %[[USP]], i64 0, metadata ![[X1:.*]], metadata ![[X1_EXPR:.*]])
+  tail call void @llvm.dbg.value(metadata i32* %x1, i64 0, metadata !10, metadata !15), !dbg !16
+  call void @capture(i32* nonnull %x1), !dbg !17
+
+; An extra non-dbg.value metadata use of %x2. Replaced with an empty metadata.
+; CHECK: call void @llvm.random.metadata.use(metadata ![[EMPTY]])
+  call void @llvm.random.metadata.use(metadata i32* %x2)
+
+; CHECK: call void @llvm.dbg.value(metadata i8* %[[USP]], i64 0, metadata ![[X2:.*]], metadata ![[X2_EXPR:.*]])
+  call void @llvm.dbg.value(metadata i32* %x2, i64 0, metadata !12, metadata !15), !dbg !18
+  call void @capture(i32* nonnull %x2), !dbg !19
+  ret void, !dbg !20
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start(i64, i8* nocapture) #1
+
+declare void @capture(i32*) #2
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end(i64, i8* nocapture) #1
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #3
+
+declare void @llvm.random.metadata.use(metadata)
+
+attributes #0 = { noinline safestack uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind }
+attributes #2 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind readnone }
+attributes #4 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 271022) (llvm/trunk 271027)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "../llvm/2.cc", directory: "/code/build-llvm")
+
+; CHECK-DAG: ![[EMPTY]] = !{}
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{!"clang version 3.9.0 (trunk 271022) (llvm/trunk 271027)"}
+!6 = distinct !DISubprogram(name: "f", linkageName: "_Z1fv", scope: !1, file: !1, line: 4, type: !7, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !9)
+!7 = !DISubroutineType(types: !8)
+!8 = !{null}
+!9 = !{!10, !12}
+
+; CHECK-DAG: ![[X1]] = !DILocalVariable(name: "x1",
+!10 = !DILocalVariable(name: "x1", scope: !6, file: !1, line: 5, type: !11)
+!11 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+
+; CHECK-DAG: ![[X2]] = !DILocalVariable(name: "x2",
+!12 = !DILocalVariable(name: "x2", scope: !6, file: !1, line: 6, type: !11)
+!13 = !DILocation(line: 5, column: 3, scope: !6)
+!14 = !DILocation(line: 6, column: 3, scope: !6)
+
+; CHECK-DAG: ![[X1_EXPR]] = !DIExpression(DW_OP_deref, DW_OP_minus, 4)
+; CHECK-DAG: ![[X2_EXPR]] = !DIExpression(DW_OP_deref, DW_OP_minus, 8)
+!15 = !DIExpression(DW_OP_deref)
+!16 = !DILocation(line: 5, column: 7, scope: !6)
+!17 = !DILocation(line: 8, column: 3, scope: !6)
+!18 = !DILocation(line: 6, column: 7, scope: !6)
+!19 = !DILocation(line: 9, column: 3, scope: !6)
+!20 = !DILocation(line: 10, column: 1, scope: !6)
+!21 = !DILocation(line: 10, column: 1, scope: !22)
+!22 = !DILexicalBlockFile(scope: !6, file: !1, discriminator: 1)
+!23 = !DIExpression()
+!24 = !DIExpression(DW_OP_minus, 42)