Document the maximum LLVM IR alignment, which is 1 << 29 or 0.5 GiB

Add verifier checks.  We already check these in the assembly parser, but
a frontend producing IR in memory wouldn't hit those checks.

llvm-svn: 213027

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index ec7ae3a77a7..9cf911b51a4 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -380,6 +380,8 @@ void Verifier::visitGlobalValue(const GlobalValue &GV) {
           "Global is external, but doesn't have external or weak linkage!",
           &GV);
 
+  Assert1(GV.getAlignment() <= Value::MaximumAlignment,
+          "huge alignment values are unsupported", &GV);
   Assert1(!GV.hasAppendingLinkage() || isa<GlobalVariable>(GV),
           "Only global variables can have appending linkage!", &GV);
 
@@ -1891,6 +1893,8 @@ void Verifier::visitLoadInst(LoadInst &LI) {
   Type *ElTy = PTy->getElementType();
   Assert2(ElTy == LI.getType(),
           "Load result type does not match pointer operand type!", &LI, ElTy);
+  Assert1(LI.getAlignment() <= Value::MaximumAlignment,
+          "huge alignment values are unsupported", &LI);
   if (LI.isAtomic()) {
     Assert1(LI.getOrdering() != Release && LI.getOrdering() != AcquireRelease,
             "Load cannot have Release ordering", &LI);
@@ -1966,6 +1970,8 @@ void Verifier::visitStoreInst(StoreInst &SI) {
   Assert2(ElTy == SI.getOperand(0)->getType(),
           "Stored value type does not match pointer operand type!",
           &SI, ElTy);
+  Assert1(SI.getAlignment() <= Value::MaximumAlignment,
+          "huge alignment values are unsupported", &SI);
   if (SI.isAtomic()) {
     Assert1(SI.getOrdering() != Acquire && SI.getOrdering() != AcquireRelease,
             "Store cannot have Acquire ordering", &SI);
@@ -1997,6 +2003,8 @@ void Verifier::visitAllocaInst(AllocaInst &AI) {
           &AI);
   Assert1(AI.getArraySize()->getType()->isIntegerTy(),
           "Alloca array size must have integer type", &AI);
+  Assert1(AI.getAlignment() <= Value::MaximumAlignment,
+          "huge alignment values are unsupported", &AI);
 
   visitInstruction(AI);
 }