[PATCH] D58224: [DebugInfo] Adjust fragment offset for big endian targets when splitting alloca in SROA

[Karl-Johan Karlsson via Phabricator via llvm-commits]

Ka-Ka created this revision.
Ka-Ka added reviewers: aprantl, bjope, dstenb.
Herald added subscribers: jdoerfert, jsji, nemanjai.
Herald added a project: LLVM.

When handling debug info fragments of types where padding have been
introduced, the offset have to be adjusted on big endian targets to
cover the correct parts of the value.


Repository:
  rL LLVM

https://reviews.llvm.org/D58224

Files:
  lib/Transforms/Scalar/SROA.cpp
  test/DebugInfo/PowerPC/sroasplit-5.ll


Index: test/DebugInfo/PowerPC/sroasplit-5.ll
===================================================================
--- /dev/null
+++ test/DebugInfo/PowerPC/sroasplit-5.ll
@@ -0,0 +1,73 @@
+; RUN: opt %s -sroa -verify -S -o - | FileCheck %s
+
+target datalayout = "E-m:e-i64:64-n32:64"
+target triple = "ppc64"
+
+; This is the big endian version of the testcase test/DebugInfo/X86/sroasplit-5.ll
+
+; When SROA is creating new smaller allocas, it may add padding.
+;
+; Verify that the fragment for this i24 start att the correct offset for big endian targets.
+; CHECK: DIExpression(DW_OP_LLVM_fragment, 0, 32)
+; CHECK: DIExpression(DW_OP_LLVM_fragment, 40, 24)
+
+%struct.prog_src_register = type { i32, i24 }
+
+define i64 @src_reg_for_float() #0 !dbg !4 {
+entry:
+  %retval = alloca %struct.prog_src_register, align 4
+  %a = alloca %struct.prog_src_register, align 4
+  %local = alloca i32, align 4
+  call void @llvm.dbg.declare(metadata %struct.prog_src_register* %a, metadata !16, metadata !17), !dbg !18
+  %0 = bitcast %struct.prog_src_register* %a to i8*, !dbg !19
+  call void @llvm.memset.p0i8.i64(i8* align 4 %0, i8 0, i64 8, i1 false), !dbg !19
+  call void @llvm.dbg.declare(metadata i32* %local, metadata !20, metadata !17), !dbg !21
+  %1 = bitcast %struct.prog_src_register* %a to i32*, !dbg !21
+  %bf.load = load i32, i32* %1, align 4, !dbg !21
+  %bf.shl = shl i32 %bf.load, 15, !dbg !21
+  %bf.ashr = ashr i32 %bf.shl, 19, !dbg !21
+  store i32 %bf.ashr, i32* %local, align 4, !dbg !21
+  %2 = bitcast %struct.prog_src_register* %retval to i8*, !dbg !22
+  %3 = bitcast %struct.prog_src_register* %a to i8*, !dbg !22
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 %2, i8* align 4 %3, i64 8, i1 false), !dbg !22
+  %4 = bitcast %struct.prog_src_register* %retval to i64*, !dbg !22
+  %5 = load i64, i64* %4, align 1, !dbg !22
+  ret i64 %5, !dbg !22
+}
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i1) #2
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i1) #2
+
+attributes #0 = { nounwind }
+attributes #1 = { nounwind readnone }
+attributes #2 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!13, !14}
+!llvm.ident = !{!15}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.7.0 ", isOptimized: false, emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
+!1 = !DIFile(filename: "<stdin>", directory: "")
+!2 = !{}
+!4 = distinct !DISubprogram(name: "src_reg_for_float", line: 7, isLocal: false, isDefinition: true, isOptimized: false, unit: !0, scopeLine: 7, file: !5, scope: !6, type: !7, retainedNodes: !2)
+!5 = !DIFile(filename: "foo.c", directory: "")
+!6 = !DIFile(filename: "foo.c", directory: "")
+!7 = !DISubroutineType(types: !8)
+!8 = !{!9}
+!9 = !DICompositeType(tag: DW_TAG_structure_type, name: "prog_src_register", line: 1, size: 64, align: 32, file: !5, elements: !10)
+!10 = !{!11}
+!11 = !DIDerivedType(tag: DW_TAG_member, name: "Index", line: 3, size: 13, align: 32, offset: 4, file: !5, scope: !9, baseType: !12)
+!12 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!13 = !{i32 2, !"Dwarf Version", i32 4}
+!14 = !{i32 2, !"Debug Info Version", i32 3}
+!15 = !{!"clang version 3.7.0 "}
+!16 = !DILocalVariable(name: "a", line: 8, scope: !4, file: !6, type: !9)
+!17 = !DIExpression()
+!18 = !DILocation(line: 8, scope: !4)
+!19 = !DILocation(line: 9, scope: !4)
+!20 = !DILocalVariable(name: "local", line: 10, scope: !4, file: !6, type: !12)
+!21 = !DILocation(line: 10, scope: !4)
+!22 = !DILocation(line: 11, scope: !4)
Index: lib/Transforms/Scalar/SROA.cpp
===================================================================
--- lib/Transforms/Scalar/SROA.cpp
+++ lib/Transforms/Scalar/SROA.cpp
@@ -4273,7 +4273,10 @@
         uint64_t AllocaSize = DL.getTypeSizeInBits(NewAI->getAllocatedType());
         // Don't include any padding.
         uint64_t Size = std::min(AllocaSize, P.size() * SizeOfByte);
-        Fragments.push_back(Fragment(NewAI, P.beginOffset() * SizeOfByte, Size));
+        uint64_t Offset = P.beginOffset() * SizeOfByte;
+        if (DL.isBigEndian())
+          Offset += std::max(AllocaSize, P.size() * SizeOfByte) - Size;
+        Fragments.push_back(Fragment(NewAI, Offset, Size));
       }
     }
     ++NumPartitions;


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