Add infrastructure for support of multiple memory constraints.

Summary:
The operand flag word for ISD::INLINEASM nodes now contains a 15-bit
memory constraint ID when the operand kind is Kind_Mem. This constraint
ID is a numeric equivalent to the constraint code string and is converted
with a target specific hook in TargetLowering.

This patch maps all memory constraints to InlineAsm::Constraint_m so there
is no functional change at this point. It just proves that using these
previously unused bits in the encoding of the flag word doesn't break anything.

The next patch will make each target preserve the current mapping of
everything to Constraint_m for itself while changing the target independent
implementation of the hook to return Constraint_Unknown appropriately. Each
target will then be adapted in separate patches to use appropriate Constraint_*
values.

Reviewers: hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8171

llvm-svn: 232027

1 files changed, 12 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 5a5827375b8..b9e6e44e353 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6598,8 +6598,14 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
         // Memory output, or 'other' output (e.g. 'X' constraint).
         assert(OpInfo.isIndirect && "Memory output must be indirect operand");
 
+        unsigned ConstraintID =
+            TLI.getInlineAsmMemConstraint(OpInfo.ConstraintCode);
+        assert(ConstraintID != InlineAsm::Constraint_Unknown &&
+               "Failed to convert memory constraint code to constraint id.");
+
         // Add information to the INLINEASM node to know about this output.
         unsigned OpFlags = InlineAsm::getFlagWord(InlineAsm::Kind_Mem, 1);
+        OpFlags = InlineAsm::getFlagWordForMem(OpFlags, ConstraintID);
         AsmNodeOperands.push_back(DAG.getTargetConstant(OpFlags, MVT::i32));
         AsmNodeOperands.push_back(OpInfo.CallOperand);
         break;
@@ -6743,8 +6749,14 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
         assert(InOperandVal.getValueType() == TLI.getPointerTy() &&
                "Memory operands expect pointer values");
 
+        unsigned ConstraintID =
+            TLI.getInlineAsmMemConstraint(OpInfo.ConstraintCode);
+        assert(ConstraintID != InlineAsm::Constraint_Unknown &&
+               "Failed to convert memory constraint code to constraint id.");
+
         // Add information to the INLINEASM node to know about this input.
         unsigned ResOpType = InlineAsm::getFlagWord(InlineAsm::Kind_Mem, 1);
+        ResOpType = InlineAsm::getFlagWordForMem(ResOpType, ConstraintID);
         AsmNodeOperands.push_back(DAG.getTargetConstant(ResOpType, MVT::i32));
         AsmNodeOperands.push_back(InOperandVal);
         break;