[llvm] r298750 - [codeview] Don't assert when the user violates the ODR

Reid Kleckner via llvm-commits llvm-commits at lists.llvm.org
Fri Mar 24 16:28:42 PDT 2017


Author: rnk
Date: Fri Mar 24 18:28:42 2017
New Revision: 298750

URL: http://llvm.org/viewvc/llvm-project?rev=298750&view=rev
Log:
[codeview] Don't assert when the user violates the ODR

If we have an array of a user-defined aggregates for which there was an
ODR violation, then the array size will not necessarily match the number
of elements times the size of the element.

Fixes PR32383

Added:
    llvm/trunk/test/DebugInfo/COFF/array-odr-violation.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp?rev=298750&r1=298749&r2=298750&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp Fri Mar 24 18:28:42 2017
@@ -1142,27 +1142,6 @@ TypeIndex CodeViewDebug::lowerTypeArray(
 
   uint64_t ElementSize = getBaseTypeSize(ElementTypeRef) / 8;
 
-
-  // We want to assert that the element type multiplied by the array lengths
-  // match the size of the overall array. However, if we don't have complete
-  // type information for the base type, we can't make this assertion. This
-  // happens if limited debug info is enabled in this case:
-  //   struct VTableOptzn { VTableOptzn(); virtual ~VTableOptzn(); };
-  //   VTableOptzn array[3];
-  // The DICompositeType of VTableOptzn will have size zero, and the array will
-  // have size 3 * sizeof(void*), and we should avoid asserting.
-  //
-  // There is a related bug in the front-end where an array of a structure,
-  // which was declared as incomplete structure first, ends up not getting a
-  // size assigned to it. (PR28303)
-  // Example:
-  //   struct A(*p)[3];
-  //   struct A { int f; } a[3];
-  bool PartiallyIncomplete = false;
-  if (Ty->getSizeInBits() == 0 || ElementSize == 0) {
-    PartiallyIncomplete = true;
-  }
-
   // Add subranges to array type.
   DINodeArray Elements = Ty->getElements();
   for (int i = Elements.size() - 1; i >= 0; --i) {
@@ -1177,16 +1156,14 @@ TypeIndex CodeViewDebug::lowerTypeArray(
     // Variable Length Array (VLA) has Count equal to '-1'.
     // Replace with Count '1', assume it is the minimum VLA length.
     // FIXME: Make front-end support VLA subrange and emit LF_DIMVARLU.
-    if (Count == -1) {
+    if (Count == -1)
       Count = 1;
-      PartiallyIncomplete = true;
-    }
 
     // Update the element size and element type index for subsequent subranges.
     ElementSize *= Count;
 
     // If this is the outermost array, use the size from the array. It will be
-    // more accurate if PartiallyIncomplete is true.
+    // more accurate if we had a VLA or an incomplete element type size.
     uint64_t ArraySize =
         (i == 0 && ElementSize == 0) ? Ty->getSizeInBits() / 8 : ElementSize;
 
@@ -1195,9 +1172,6 @@ TypeIndex CodeViewDebug::lowerTypeArray(
     ElementTypeIndex = TypeTable.writeKnownType(AR);
   }
 
-  (void)PartiallyIncomplete;
-  assert(PartiallyIncomplete || ElementSize == (Ty->getSizeInBits() / 8));
-
   return ElementTypeIndex;
 }
 

Added: llvm/trunk/test/DebugInfo/COFF/array-odr-violation.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/COFF/array-odr-violation.ll?rev=298750&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/COFF/array-odr-violation.ll (added)
+++ llvm/trunk/test/DebugInfo/COFF/array-odr-violation.ll Fri Mar 24 18:28:42 2017
@@ -0,0 +1,100 @@
+; This tests that emitting CodeView arrays doesn't assert when an ODR violation
+; makes our array dimension size calculations inaccurate. (PR32383)
+
+; Here was the scenario:
+; $ cat a.cpp
+; typedef union YYSTYPE { int x; } YYSTYPE;
+; YYSTYPE a;
+; $ cat b.cpp
+; typedef union YYSTYPE { char x; } YYSTYPE;
+; void fn1() { YYSTYPE a[1]; }
+; $ clang-cl -c -Zi -flto a.cpp b.cpp
+; $ llvm-link a.obj b.obj -S -o t.ll  # This is the test case IR.
+; $ llc t.ll  # Used to assert
+
+; RUN: llc < %s | FileCheck %s
+
+; FIXME: sizeof(a) in the user program is 1, but we claim it is 4 because
+; sometimes the frontend lies to us. See array-types-advanced.ll for an example.
+;
+; CHECK: Array ({{.*}}) {
+; CHECK:   TypeLeafKind: LF_ARRAY (0x1503)
+; CHECK:   ElementType: YYSTYPE ({{.*}})
+; CHECK:   IndexType: unsigned __int64 (0x23)
+; CHECK:   SizeOf: 4
+; CHECK:   Name:
+; CHECK: }
+
+; sizeof(YYSTYPE) == 4
+; CHECK: Union ({{.*}}) {
+; CHECK:   TypeLeafKind: LF_UNION (0x1506)
+; CHECK:   MemberCount: 1
+; CHECK:   Properties [ (0x600)
+; CHECK:     HasUniqueName (0x200)
+; CHECK:     Sealed (0x400)
+; CHECK:   ]
+; CHECK:   FieldList: <field list>
+; CHECK:   SizeOf: 4
+; CHECK:   Name: YYSTYPE
+; CHECK:   LinkageName: .?ATYYSTYPE@@
+; CHECK: }
+
+; ModuleID = 'llvm-link'
+source_filename = "llvm-link"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.10.24728"
+
+%union.YYSTYPE = type { i32 }
+%union.YYSTYPE.0 = type { i8 }
+
+@"\01?a@@3TYYSTYPE@@A" = global %union.YYSTYPE zeroinitializer, align 4, !dbg !0
+
+; Function Attrs: noinline nounwind sspstrong uwtable
+define void @"\01?fn1@@YAXXZ"() #0 !dbg !21 {
+entry:
+  %a = alloca [1 x %union.YYSTYPE.0], align 1
+  call void @llvm.dbg.declare(metadata [1 x %union.YYSTYPE.0]* %a, metadata !24, metadata !29), !dbg !30
+  ret void, !dbg !30
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+attributes #0 = { noinline nounwind sspstrong uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "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" "no-signed-zeros-fp-math"="false" "no-trapping-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 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!2, !11}
+!llvm.ident = !{!13, !13}
+!llvm.module.flags = !{!14, !18, !19, !20}
+
+!0 = !DIGlobalVariableExpression(var: !1)
+!1 = distinct !DIGlobalVariable(name: "a", linkageName: "\01?a@@3TYYSTYPE@@A", scope: !2, file: !3, line: 2, type: !6, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 5.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
+!3 = !DIFile(filename: "a.cpp", directory: "C:\5Csrc\5Cllvm-project\5Cbuild", checksumkind: CSK_MD5, checksum: "c0005139aa3df153c30d8c6953390a4b")
+!4 = !{}
+!5 = !{!0}
+!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "YYSTYPE", file: !3, line: 1, baseType: !7)
+!7 = distinct !DICompositeType(tag: DW_TAG_union_type, name: "YYSTYPE", file: !3, line: 1, size: 32, elements: !8, identifier: ".?ATYYSTYPE@@")
+!8 = !{!9}
+!9 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !7, file: !3, line: 1, baseType: !10, size: 32)
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !12, producer: "clang version 5.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4)
+!12 = !DIFile(filename: "b.cpp", directory: "C:\5Csrc\5Cllvm-project\5Cbuild", checksumkind: CSK_MD5, checksum: "9cfd390d8827beab36769147bb037abc")
+!13 = !{!"clang version 5.0.0 "}
+!14 = !{i32 6, !"Linker Options", !15}
+!15 = !{!16, !17}
+!16 = !{!"/DEFAULTLIB:libcmt.lib"}
+!17 = !{!"/DEFAULTLIB:oldnames.lib"}
+!18 = !{i32 2, !"CodeView", i32 1}
+!19 = !{i32 2, !"Debug Info Version", i32 3}
+!20 = !{i32 1, !"PIC Level", i32 2}
+!21 = distinct !DISubprogram(name: "fn1", linkageName: "\01?fn1@@YAXXZ", scope: !12, file: !12, line: 2, type: !22, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !11, variables: !4)
+!22 = !DISubroutineType(types: !23)
+!23 = !{null}
+!24 = !DILocalVariable(name: "a", scope: !21, file: !12, line: 2, type: !25)
+!25 = !DICompositeType(tag: DW_TAG_array_type, baseType: !26, size: 8, elements: !27)
+!26 = !DIDerivedType(tag: DW_TAG_typedef, name: "YYSTYPE", file: !12, line: 1, baseType: !7)
+!27 = !{!28}
+!28 = !DISubrange(count: 1)
+!29 = !DIExpression()
+!30 = !DILocation(line: 2, scope: !21)




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