From ca93687eb28f2c7f2d5d9a568e7c3e31ad6ff811 Mon Sep 17 00:00:00 2001
From: Chen Zheng <czhengsz@cn.ibm.com>
Date: Sun, 11 Apr 2021 23:13:17 -0400
Subject: [PATCH] [Debug-Info] make fortran CHARACTER(1) type as valid unsigned
 type

This resolves https://bugs.llvm.org/show_bug.cgi?id=49872

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D100015
---
 lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp |  6 +++
 test/CodeGen/Generic/pr49872.ll             | 48 +++++++++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 test/CodeGen/Generic/pr49872.ll

diff --git a/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp b/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
index b9a9e1cfaee..70a4d5fe7ee 100644
--- a/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
+++ b/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
@@ -174,6 +174,12 @@ uint64_t DebugHandlerBase::getBaseTypeSize(const DIType *Ty) {
 }
 
 bool DebugHandlerBase::isUnsignedDIType(const DIType *Ty) {
+  // SROA may generate dbg value intrinsics to assign an unsigned value to a
+  // Fortran CHARACTER(1) type variables. Make them as unsigned.
+  if (isa<DIStringType>(Ty)) {
+    assert((Ty->getSizeInBits()) == 8 && "Not a valid unsigned type!");
+    return true;
+  }
   if (auto *CTy = dyn_cast<DICompositeType>(Ty)) {
     // FIXME: Enums without a fixed underlying type have unknown signedness
     // here, leading to incorrectly emitted constants.
diff --git a/test/CodeGen/Generic/pr49872.ll b/test/CodeGen/Generic/pr49872.ll
new file mode 100644
index 00000000000..132cd5da25b
--- /dev/null
+++ b/test/CodeGen/Generic/pr49872.ll
@@ -0,0 +1,48 @@
+; REQUIRES: powerpc-registered-target
+; RUN: llc -mtriple powerpc64le-unknown-linux-gnu -filetype=obj < %s | \
+; RUN:   llvm-dwarfdump -debug-info - | FileCheck %s
+
+; PR49872
+; Check an integer constant for Fortran CHARACTER(1) will not cause a crash in
+; DebugHandlerBase::isUnsignedDIType when calling DwarfUnit::addConstantValue
+
+; CHECK:             DW_TAG_formal_parameter
+; CHECK:                 DW_AT_const_value     (122)
+; CHECK:                 DW_AT_name    ("arg")
+; CHECK:                 DW_AT_type    ([[TYPE:[a-z0-9]+]] "char string")
+; CHECK: [[TYPE]]:   DW_TAG_string_type
+; CHECK:                 DW_AT_name      ("char string")
+; CHECK:                 DW_AT_byte_size (0x01)
+
+source_filename = "1.ll"
+
+define dso_local void @s1_after_sroa([1 x i8] %arg) local_unnamed_addr #0 !dbg !5 {
+s1_entry:
+  call void @llvm.dbg.value(metadata i8 122, metadata !10, metadata !DIExpression()), !dbg !11
+  ret void, !dbg !12
+}
+
+declare void @llvm.dbg.value(metadata, metadata, metadata) #5
+
+!llvm.module.flags = !{!0, !1}
+!llvm.dbg.cu = !{!2}
+
+!0 = !{i32 2, !"Dwarf Version", i32 3}
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+!2 = distinct !DICompileUnit(language: DW_LANG_Fortran95, file: !3, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, splitDebugInlining: false)
+!3 = !DIFile(filename: "1.f", directory: ".")
+!4 = !{}
+!5 = distinct !DISubprogram(name: "s1", linkageName: "s1", scope: !3, file: !3, line: 1, type: !6, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !4)
+!6 = !DISubroutineType(types: !7)
+!7 = !{!8, !9}
+!8 = !DIBasicType(tag: DW_TAG_unspecified_type, name: "void")
+!9 = !DIStringType(name: "char string", size: 8)
+!10 = !DILocalVariable(name: "arg", arg: 1, scope: !5, file: !3, type: !9)
+!11 = !DILocation(line: 0, scope: !5)
+!12 = !DILocation(line: 4, scope: !5)
+!13 = !DILocation(line: 5, scope: !5)
+!14 = distinct !DISubprogram(name: "p", linkageName: "main", scope: !3, file: !3, line: 7, type: !15, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !4)
+!15 = !DISubroutineType(types: !16)
+!16 = !{!17}
+!17 = !DIBasicType(name: "INTEGER", size: 32, encoding: DW_ATE_signed)
+!18 = !DILocation(line: 8, scope: !14)