Fix left shifts of negative integers in AArch64 InstPrinter/Disassembler

Summary:
Left shift of negative integer is an undefined behavior, and
is reported by UBSan. It's ok for imm values to be negative, so we can
just replace left shifts with multiplications.

Test Plan: check-llvm test suite

Reviewers: t.p.northover

Reviewed By: t.p.northover

Subscribers: aemerson, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D5132

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216910 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp b/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
index 9726b2a..9e86188 100644 (file)
--- a/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
+++ b/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
@@ -610,7 +610,7 @@ static DecodeStatus DecodePCRelLabel19(llvm::MCInst &Inst, unsigned Imm,
   if (ImmVal & (1 << (19 - 1)))
     ImmVal |= ~((1LL << 19) - 1);
 
-  if (!Dis->tryAddingSymbolicOperand(Inst, ImmVal << 2, Addr,
+  if (!Dis->tryAddingSymbolicOperand(Inst, ImmVal *  4, Addr,
                                      Inst.getOpcode() != AArch64::LDRXl, 0, 4))
     Inst.addOperand(MCOperand::CreateImm(ImmVal));
   return Success;
@@ -1506,7 +1506,7 @@ static DecodeStatus DecodeUnconditionalBranch(llvm::MCInst &Inst, uint32_t insn,
   if (imm & (1 << (26 - 1)))
     imm |= ~((1LL << 26) - 1);
 
-  if (!Dis->tryAddingSymbolicOperand(Inst, imm << 2, Addr, true, 0, 4))
+  if (!Dis->tryAddingSymbolicOperand(Inst, imm * 4, Addr, true, 0, 4))
     Inst.addOperand(MCOperand::CreateImm(imm));
 
   return Success;
@@ -1548,7 +1548,7 @@ static DecodeStatus DecodeTestAndBranch(llvm::MCInst &Inst, uint32_t insn,
   else
     DecodeGPR64RegisterClass(Inst, Rt, Addr, Decoder);
   Inst.addOperand(MCOperand::CreateImm(bit));
-  if (!Dis->tryAddingSymbolicOperand(Inst, dst << 2, Addr, true, 0, 4))
+  if (!Dis->tryAddingSymbolicOperand(Inst, dst * 4, Addr, true, 0, 4))
     Inst.addOperand(MCOperand::CreateImm(dst));
 
   return Success;

diff --git a/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.cpp b/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.cpp
index 848153b..0091ab3 100644 (file)
--- a/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.cpp
+++ b/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.cpp
@@ -1223,7 +1223,7 @@ void AArch64InstPrinter::printAlignedLabel(const MCInst *MI, unsigned OpNum,
   // If the label has already been resolved to an immediate offset (say, when
   // we're running the disassembler), just print the immediate.
   if (Op.isImm()) {
-    O << "#" << (Op.getImm() << 2);
+    O << "#" << (Op.getImm() * 4);
     return;
   }
 
@@ -1247,7 +1247,7 @@ void AArch64InstPrinter::printAdrpLabel(const MCInst *MI, unsigned OpNum,
   // If the label has already been resolved to an immediate offset (say, when
   // we're running the disassembler), just print the immediate.
   if (Op.isImm()) {
-    O << "#" << (Op.getImm() << 12);
+    O << "#" << (Op.getImm() * (1 << 12));
     return;
   }