[WinEH] Require token linkage in EH pad/ret signatures

Summary:
WinEHPrepare is going to require that cleanuppad and catchpad produce values
of token type which are consumed by any cleanupret or catchret exiting the
pad.  This change updates the signatures of those operators to require/enforce
that the type produced by the pads is token type and that the rets have an
appropriate argument.

The catchpad argument of a `CatchReturnInst` must be a `CatchPadInst` (and
similarly for `CleanupReturnInst`/`CleanupPadInst`).  To accommodate that
restriction, this change adds a notion of an operator constraint to both
LLParser and BitcodeReader, allowing appropriate sentinels to be constructed
for forward references and appropriate error messages to be emitted for
illegal inputs.

Also add a verifier rule (noted in LangRef) that a catchpad with a catchpad
predecessor must have no other predecessors; this ensures that WinEHPrepare
will see the expected linear relationship between sibling catches on the
same try.

Lastly, remove some superfluous/vestigial casts from instruction operand
setters operating on BasicBlocks.

Reviewers: rnk, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12108

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245797 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 6 deletions

diff --git a/lib/AsmParser/LLParser.h b/lib/AsmParser/LLParser.h
index 96fb06a1f29..8b7e9560a69 100644
--- a/lib/AsmParser/LLParser.h
+++ b/lib/AsmParser/LLParser.h
@@ -108,6 +108,14 @@ namespace llvm {
       unsigned MDKind, MDSlot;
     };
 
+    /// Indicates which operator an operand allows (for the few operands that
+    /// may only reference a certain operator).
+    enum OperatorConstraint {
+      OC_None = 0,  // No constraint
+      OC_CatchPad,  // Must be CatchPadInst
+      OC_CleanupPad // Must be CleanupPadInst
+    };
+
     SmallVector<Instruction*, 64> InstsWithTBAATag;
 
     // Type resolution handling data structures.  The location is set when we
@@ -329,8 +337,10 @@ namespace llvm {
       /// GetVal - Get a value with the specified name or ID, creating a
       /// forward reference record if needed.  This can return null if the value
       /// exists but does not have the right type.
-      Value *GetVal(const std::string &Name, Type *Ty, LocTy Loc);
-      Value *GetVal(unsigned ID, Type *Ty, LocTy Loc);
+      Value *GetVal(const std::string &Name, Type *Ty, LocTy Loc,
+                    OperatorConstraint OC = OC_None);
+      Value *GetVal(unsigned ID, Type *Ty, LocTy Loc,
+                    OperatorConstraint OC = OC_None);
 
       /// SetInstName - After an instruction is parsed and inserted into its
       /// basic block, this installs its name.
@@ -352,12 +362,15 @@ namespace llvm {
     };
 
     bool ConvertValIDToValue(Type *Ty, ValID &ID, Value *&V,
-                             PerFunctionState *PFS);
+                             PerFunctionState *PFS,
+                             OperatorConstraint OC = OC_None);
 
     bool parseConstantValue(Type *Ty, Constant *&C);
-    bool ParseValue(Type *Ty, Value *&V, PerFunctionState *PFS);
-    bool ParseValue(Type *Ty, Value *&V, PerFunctionState &PFS) {
-      return ParseValue(Ty, V, &PFS);
+    bool ParseValue(Type *Ty, Value *&V, PerFunctionState *PFS,
+                    OperatorConstraint OC = OC_None);
+    bool ParseValue(Type *Ty, Value *&V, PerFunctionState &PFS,
+                    OperatorConstraint OC = OC_None) {
+      return ParseValue(Ty, V, &PFS, OC);
     }
     bool ParseValue(Type *Ty, Value *&V, LocTy &Loc,
                     PerFunctionState &PFS) {