From 492d76b02ec5dd84fa59f79ce83cd3e5ae6603fe Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Wed, 29 Aug 2012 23:52:52 +0000 Subject: [PATCH] Verify the order of tied operands in inline asm. When there are multiple tied use-def pairs on an inline asm instruction, the tied uses must appear in the same order as the defs. It is possible to write an LLVM IR inline asm instruction that breaks this constraint, but there is no reason for a front end to emit the operands out of order. The gnu inline asm syntax specifies tied operands as a single read/write constraint "+r", so ouf of order operands are not possible. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162878 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/InstrEmitter.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp index 5927838b533..4d09c444945 100644 --- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp +++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp @@ -895,6 +895,7 @@ EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, // Remember to operand index of the group flags. SmallVector GroupIdx; + unsigned PrevDefGroup = 0; // Add all of the operand registers to the instruction. for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) { @@ -943,9 +944,20 @@ EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, if (InlineAsm::getKind(Flags) == InlineAsm::Kind_RegUse) { unsigned DefGroup = 0; if (InlineAsm::isUseOperandTiedToDef(Flags, DefGroup)) { + // Check that the def groups are monotonically increasing. + // Otherwise, the tied uses and defs won't line up, and + // MI::findTiedOperandIdx() will find the wrong operand. This + // should be automatically enforced by the front ends when + // translating "+" constraints into tied def+use pairs. + assert(DefGroup >= PrevDefGroup && + "Tied inline asm operands must be in increasing order."); + PrevDefGroup = DefGroup; + unsigned DefIdx = GroupIdx[DefGroup] + 1; unsigned UseIdx = GroupIdx.back() + 1; for (unsigned j = 0; j != NumVals; ++j) { + assert(!MI->getOperand(DefIdx + j).isTied() && + "Def is already tied to another use"); MI->getOperand(DefIdx + j).setIsTied(); MI->getOperand(UseIdx + j).setIsTied(); }