Add an inalloca flag to allocas

Summary:
The only current use of this flag is to mark the alloca as dynamic, even
if its in the entry block.  The stack adjustment for the alloca can
never be folded into the prologue because the call may clear it and it
has to be allocated at the top of the stack.

Reviewers: majnemer

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2571

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199525 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 22 insertions, 10 deletions

diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index a1b5f9946c..ab4b48bf6e 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -4069,31 +4069,42 @@ bool LLParser::ParseCall(Instruction *&Inst, PerFunctionState &PFS,
 //===----------------------------------------------------------------------===//
 
 /// ParseAlloc
-///   ::= 'alloca' Type (',' TypeAndValue)? (',' OptionalInfo)?
+///   ::= 'alloca' Type (',' 'inalloca')? (',' TypeAndValue)? (',' OptionalInfo)?
 int LLParser::ParseAlloc(Instruction *&Inst, PerFunctionState &PFS) {
   Value *Size = 0;
   LocTy SizeLoc;
   unsigned Alignment = 0;
+  bool IsInAlloca = false;
   Type *Ty = 0;
   if (ParseType(Ty)) return true;
 
   bool AteExtraComma = false;
   if (EatIfPresent(lltok::comma)) {
-    if (Lex.getKind() == lltok::kw_align) {
-      if (ParseOptionalAlignment(Alignment)) return true;
-    } else if (Lex.getKind() == lltok::MetadataVar) {
-      AteExtraComma = true;
-    } else {
-      if (ParseTypeAndValue(Size, SizeLoc, PFS) ||
-          ParseOptionalCommaAlign(Alignment, AteExtraComma))
-        return true;
+    bool HaveComma = true;
+    if (EatIfPresent(lltok::kw_inalloca)) {
+      IsInAlloca = true;
+      HaveComma = EatIfPresent(lltok::comma);
+    }
+
+    if (HaveComma) {
+      if (Lex.getKind() == lltok::kw_align) {
+        if (ParseOptionalAlignment(Alignment)) return true;
+      } else if (Lex.getKind() == lltok::MetadataVar) {
+        AteExtraComma = true;
+      } else {
+        if (ParseTypeAndValue(Size, SizeLoc, PFS) ||
+            ParseOptionalCommaAlign(Alignment, AteExtraComma))
+          return true;
+      }
     }
   }
 
   if (Size && !Size->getType()->isIntegerTy())
     return Error(SizeLoc, "element count must have integer type");
 
-  Inst = new AllocaInst(Ty, Size, Alignment);
+  AllocaInst *AI = new AllocaInst(Ty, Size, Alignment);
+  AI->setUsedWithInAlloca(IsInAlloca);
+  Inst = AI;
   return AteExtraComma ? InstExtraComma : InstNormal;
 }
 
diff --git a/lib/AsmParser/LLParser.h b/lib/AsmParser/LLParser.h
index c62979e6f2..d25374ff05 100644
--- a/lib/AsmParser/LLParser.h
+++ b/lib/AsmParser/LLParser.h
@@ -211,6 +211,7 @@ namespace llvm {
                                AtomicOrdering &Ordering);
     bool ParseOptionalStackAlignment(unsigned &Alignment);
     bool ParseOptionalCommaAlign(unsigned &Alignment, bool &AteExtraComma);
+    bool ParseOptionalCommaInAlloca(bool &IsInAlloca);
     bool ParseIndexList(SmallVectorImpl<unsigned> &Indices,bool &AteExtraComma);
     bool ParseIndexList(SmallVectorImpl<unsigned> &Indices) {
       bool AteExtraComma;