[Verifier] Check that debug values have proper size

Summary:
Teach the Verifier to make sure that the storage size given to llvm.dbg.declare
or the value size given to llvm.dbg.value agree with what is declared in
DebugInfo. This is implicitly assumed in a number of passes (e.g. in SROA).
Additionally this catches a number of common mistakes, such as passing a
pointer when a value was intended or vice versa.

One complication comes from stack coloring which modifies the original IR when
it merges allocas in order to make sure that if AA falls back to the IR it gets
the correct result. However, given this new invariant, indiscriminately
replacing one alloca by a different (differently sized one) is no longer valid.
Fix this by just undefing out any use of the alloca in a dbg.declare in this
case.

Additionally, I had to fix a number of test cases. Of particular note:
- I regenerated dbg-changes-codegen-branch-folding.ll from the given source as
  it was affected by the bug fixed in r256077
- two-cus-from-same-file.ll was changed to avoid having a variable-typed debug
  variable as that would depend on the target, even though this test is
  supposed to be generic
- I had to manually declared size/align for reference type. See also the
  discussion for D14275/r253186.
- fpstack-debuginstr-kill.ll required changing `double` to `long double`
- most others were just a question of adding OP_deref

Reviewers: aprantl
Differential Revision: http://reviews.llvm.org/D14276

llvm-svn: 257105

llvm/lib/CodeGen/StackColoring.cpp

@@ -21,7 +21,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/CodeGen/Passes.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/PostOrderIterator.h"
@@ -40,13 +39,15 @@
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/PseudoSourceValue.h"
 #include "llvm/CodeGen/SlotIndexes.h"
 #include "llvm/CodeGen/StackProtector.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -494,10 +495,21 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
     // upcoming replacement.
     SP->adjustForColoring(From, To);
 
+    // The new alloca might not be valid in a llvm.dbg.declare for this
+    // variable, so undef out the use to make the verifier happy.
+    AllocaInst *FromAI = const_cast<AllocaInst *>(From);
+    if (FromAI->isUsedByMetadata())
+      ValueAsMetadata::handleRAUW(FromAI, UndefValue::get(FromAI->getType()));
+    for (auto &Use : FromAI->uses()) {
+      if (BitCastInst *BCI = dyn_cast<BitCastInst>(Use.get()))
+        if (BCI->isUsedByMetadata())
+          ValueAsMetadata::handleRAUW(BCI, UndefValue::get(BCI->getType()));
+    }
+
     // Note that this will not replace uses in MMOs (which we'll update below),
     // or anywhere else (which is why we won't delete the original
     // instruction).
-    const_cast<AllocaInst *>(From)->replaceAllUsesWith(Inst);
+    FromAI->replaceAllUsesWith(Inst);
   }
 
   // Remap all instructions to the new stack slots.

llvm/lib/IR/Verifier.cpp

@@ -432,8 +432,7 @@ class Verifier : public InstVisitor<Verifier>, VerifierSupport {
   // Module-level debug info verification...
   void verifyTypeRefs();
   template <class MapTy>
-  void verifyBitPieceExpression(const DbgInfoIntrinsic &I,
-                                const MapTy &TypeRefs);
+  void verifyDIExpression(const DbgInfoIntrinsic &I, const MapTy &TypeRefs);
   void visitUnresolvedTypeRef(const MDString *S, const MDNode *N);
 };
 } // End anonymous namespace
@@ -3854,15 +3853,34 @@ static uint64_t getVariableSize(const DILocalVariable &V, const MapTy &Map) {
 }
 
 template <class MapTy>
-void Verifier::verifyBitPieceExpression(const DbgInfoIntrinsic &I,
-                                        const MapTy &TypeRefs) {
+void Verifier::verifyDIExpression(const DbgInfoIntrinsic &I,
+                                  const MapTy &TypeRefs) {
   DILocalVariable *V;
   DIExpression *E;
+  const Value *Arg;
+  uint64_t ArgumentTypeSizeInBits = 0;
   if (auto *DVI = dyn_cast<DbgValueInst>(&I)) {
+    Arg = DVI->getValue();
+    if (Arg)
+      ArgumentTypeSizeInBits =
+          M->getDataLayout().getTypeAllocSizeInBits(Arg->getType());
     V = dyn_cast_or_null<DILocalVariable>(DVI->getRawVariable());
     E = dyn_cast_or_null<DIExpression>(DVI->getRawExpression());
   } else {
     auto *DDI = cast<DbgDeclareInst>(&I);
+    // For declare intrinsics, get the total size of the alloca, to allow
+    // case where the variable may span more than one element.
+    Arg = DDI->getAddress();
+    if (Arg)
+      Arg = Arg->stripPointerCasts();
+    const AllocaInst *AI = dyn_cast_or_null<AllocaInst>(Arg);
+    if (AI) {
+      // We can only say something about constant size allocations
+      if (const ConstantInt *CI = dyn_cast<ConstantInt>(AI->getArraySize()))
+        ArgumentTypeSizeInBits =
+            CI->getLimitedValue() *
+            M->getDataLayout().getTypeAllocSizeInBits(AI->getAllocatedType());
+    }
     V = dyn_cast_or_null<DILocalVariable>(DDI->getRawVariable());
     E = dyn_cast_or_null<DIExpression>(DDI->getRawExpression());
   }
@@ -3871,10 +3889,6 @@ void Verifier::verifyBitPieceExpression(const DbgInfoIntrinsic &I,
   if (!V || !E || !E->isValid())
     return;
 
-  // Nothing to do if this isn't a bit piece expression.
-  if (!E->isBitPiece())
-    return;
-
   // The frontend helps out GDB by emitting the members of local anonymous
   // unions as artificial local variables with shared storage. When SROA splits
   // the storage for artificial local variables that are smaller than the entire
@@ -3890,11 +3904,33 @@ void Verifier::verifyBitPieceExpression(const DbgInfoIntrinsic &I,
   if (!VarSize)
     return;
 
-  unsigned PieceSize = E->getBitPieceSize();
-  unsigned PieceOffset = E->getBitPieceOffset();
-  Assert(PieceSize + PieceOffset <= VarSize,
-         "piece is larger than or outside of variable", &I, V, E);
-  Assert(PieceSize != VarSize, "piece covers entire variable", &I, V, E);
+  if (E->isBitPiece()) {
+    unsigned PieceSize = E->getBitPieceSize();
+    unsigned PieceOffset = E->getBitPieceOffset();
+    Assert(PieceSize + PieceOffset <= VarSize,
+           "piece is larger than or outside of variable", &I, V, E);
+    Assert(PieceSize != VarSize, "piece covers entire variable", &I, V, E);
+    return;
+  }
+
+  if (!ArgumentTypeSizeInBits)
+    return; // We were unable to determine the size of the argument
+
+  if (E->getNumElements() == 0) {
+    // In the case where the expression is empty, verify the size of the
+    // argument. Doing this in the general case would require looking through
+    // any dereferences that may be in the expression.
+    Assert(ArgumentTypeSizeInBits == VarSize,
+           "size of passed value (" + std::to_string(ArgumentTypeSizeInBits) +
+               ") does not match size of declared variable (" +
+               std::to_string(VarSize) + ")",
+           &I, Arg, V, V->getType(), E);
+  } else if (E->getElement(0) == dwarf::DW_OP_deref) {
+    Assert(ArgumentTypeSizeInBits == M->getDataLayout().getPointerSizeInBits(),
+           "the operation of the expression is a deref, but the passed value "
+           "is not pointer sized",
+           &I, Arg, V, V->getType(), E);
+  }
 }
 
 void Verifier::visitUnresolvedTypeRef(const MDString *S, const MDNode *N) {
@@ -3927,7 +3963,7 @@ void Verifier::verifyTypeRefs() {
     for (const BasicBlock &BB : F)
       for (const Instruction &I : BB)
         if (auto *DII = dyn_cast<DbgInfoIntrinsic>(&I))
-          verifyBitPieceExpression(*DII, TypeRefs);
+          verifyDIExpression(*DII, TypeRefs);
 
   // Return early if all typerefs were resolved.
   if (UnresolvedTypeRefs.empty())

llvm/test/CodeGen/ARM/2010-08-04-StackVariable.ll

@@ -1,6 +1,9 @@
 ; RUN: llc -O0 -mtriple=arm-apple-darwin < %s | grep DW_OP_breg
 ; Use DW_OP_breg in variable's location expression if the variable is in a stack slot.
 
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:64:64-v128:128:128-a0:0:64"
+target triple = "arm-apple-darwin"
+
 %struct.SVal = type { i8*, i32 }
 
 define i32 @_Z3fooi4SVal(i32 %i, %struct.SVal* noalias %location) nounwind ssp !dbg !17 {
@@ -78,7 +81,7 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) nounwind readnon
 !llvm.module.flags = !{!49}
 
 !0 = !DISubprogram(name: "SVal", line: 11, isLocal: false, isDefinition: false, virtualIndex: 6, isOptimized: false, file: !48, scope: !1, type: !14)
-!1 = !DICompositeType(tag: DW_TAG_structure_type, name: "SVal", line: 1, size: 128, align: 64, file: !48, elements: !4)
+!1 = !DICompositeType(tag: DW_TAG_structure_type, name: "SVal", line: 1, size: 64, align: 64, file: !48, elements: !4)
 !2 = !DIFile(filename: "small.cc", directory: "/Users/manav/R8248330")
 !3 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "4.2.1 (Based on Apple Inc. build 5658) (LLVM build)", isOptimized: false, emissionKind: 1, file: !48, enums: !47, retainedTypes: !47, subprograms: !46, globals: !47, imports:  !47)
 !4 = !{!5, !7, !0, !9}
@@ -103,14 +106,14 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) nounwind readnon
 !23 = !DILocalVariable(name: "i", line: 16, arg: 1, scope: !17, file: !2, type: !13)
 !24 = !DILocation(line: 16, scope: !17)
 !25 = !DILocalVariable(name: "location", line: 16, arg: 2, scope: !17, file: !2, type: !26)
-!26 = !DIDerivedType(tag: DW_TAG_reference_type, name: "SVal", size: 64, align: 64, file: !48, scope: !2, baseType: !1)
+!26 = !DIDerivedType(tag: DW_TAG_reference_type, name: "SVal", size: 32, align: 32, file: !48, scope: !2, baseType: !1)
 !27 = !DILocation(line: 17, scope: !28)
 !28 = distinct !DILexicalBlock(line: 16, column: 0, file: !2, scope: !17)
 !29 = !DILocation(line: 18, scope: !28)
 !30 = !DILocation(line: 20, scope: !28)
 !31 = !DILocalVariable(name: "this", line: 11, arg: 1, scope: !16, file: !2, type: !32)
-!32 = !DIDerivedType(tag: DW_TAG_const_type, size: 64, align: 64, flags: DIFlagArtificial, file: !48, scope: !2, baseType: !33)
-!33 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, file: !48, scope: !2, baseType: !1)
+!32 = !DIDerivedType(tag: DW_TAG_const_type, flags: DIFlagArtificial, file: !48, scope: !2, baseType: !33)
+!33 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 32, align: 32, file: !48, scope: !2, baseType: !1)
 !34 = !DILocation(line: 11, scope: !16)
 !35 = !DILocation(line: 11, scope: !36)
 !36 = distinct !DILexicalBlock(line: 11, column: 0, file: !48, scope: !37)

llvm/test/CodeGen/MIR/X86/invalid-metadata-node-type.mir

@@ -6,7 +6,7 @@
   entry:
     %x.i = alloca i8, align 1
     %y.i = alloca [256 x i8], align 16
-    %0 = bitcast [256 x i8]* %y.i to i8*
+    %0 = bitcast i8* %x.i to i8*
     br label %for.body
 
   for.body:

llvm/test/CodeGen/MIR/X86/stack-object-debug-info.mir

@@ -35,11 +35,14 @@
   !1 = !DIFile(filename: "t.c", directory: "")
   !2 = !{}
   !3 = !{i32 1, !"Debug Info Version", i32 3}
-  !4 = !DILocalVariable(name: "x", scope: !5, file: !1, line: 16, type: !6)
+  !4 = !DILocalVariable(name: "x", scope: !5, file: !1, line: 16, type: !9)
   !5 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false)
   !6 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
   !7 = !DIExpression()
   !8 = !DILocation(line: 0, scope: !5)
+  !9 = !DICompositeType(tag: DW_TAG_array_type, baseType: !6, size: 2048, align: 8, elements: !10)
+  !10 = !{!11}
+  !11 = !DISubrange(count: 256)
 ...
 ---
 name:            foo
@@ -50,7 +53,7 @@ frameInfo:
 # CHECK-LABEL: foo
 # CHECK: stack:
 # CHECK:  - { id: 0, name: y.i, offset: 0, size: 256, alignment: 16, di-variable: '!4',
-# CHECK-NEXT: di-expression: '!7', di-location: '!8' }
+# CHECK-NEXT: di-expression: '!10', di-location: '!11' }
 stack:
   - { id: 0, name: y.i, offset: 0, size: 256, alignment: 16, di-variable: '!4',
       di-expression: '!7', di-location: '!8' }

llvm/test/CodeGen/X86/2012-11-30-regpres-dbg.ll

@@ -40,7 +40,7 @@ invoke.cont44:                                    ; preds = %if.end
 !1 = !{!2}
 !2 = distinct !DISubprogram(name: "test", isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, scopeLine: 1, file: !6, scope: !5, type: !7)
 !3 = !DILocalVariable(name: "callback", line: 214, scope: !2, type: !4)
-!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "btCompoundLeafCallback", line: 90, size: 512, align: 64, file: !6)
+!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "btCompoundLeafCallback", line: 90, size: 64, align: 64, file: !6)
 !5 = !DIFile(filename: "MultiSource/Benchmarks/Bullet/btCompoundCollisionAlgorithm.cpp", directory: "MultiSource/Benchmarks/Bullet")
 !6 = !DIFile(filename: "MultiSource/Benchmarks/Bullet/btCompoundCollisionAlgorithm.cpp", directory: "MultiSource/Benchmarks/Bullet")
 !7 = !DISubroutineType(types: !9)

llvm/test/CodeGen/X86/MachineSink-DbgValue.ll

@@ -36,9 +36,9 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) nounwind readnon
 !5 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !6 = !DILocalVariable(name: "i", line: 2, arg: 1, scope: !1, file: !2, type: !5)
 !7 = !DILocalVariable(name: "c", line: 2, arg: 2, scope: !1, file: !2, type: !8)
-!8 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, scope: !0, baseType: !9)
+!8 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, scope: !0, baseType: !5)
 !9 = !DIBasicType(tag: DW_TAG_base_type, name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
-!10 = !DILocalVariable(name: "a", line: 3, scope: !11, file: !2, type: !9)
+!10 = !DILocalVariable(name: "a", line: 3, scope: !11, file: !2, type: !5)
 !11 = distinct !DILexicalBlock(line: 2, column: 25, file: !20, scope: !1)
 !12 = !DILocation(line: 2, column: 13, scope: !1)
 !13 = !DILocation(line: 2, column: 22, scope: !1)