ARM: Correct printing of pre-indexed operands.

According to the ARM reference manual, constant offsets are mandatory for pre-indexed addressing modes.
The MC disassembler was not obeying this when the offset is 0.
It was producing instructions like: str r0, [r1]!.
Correct syntax is: str r0, [r1, #0]!.

This change modifies the dumping of operands so that the offset is always printed, regardless of its value, when pre-indexed addressing mode is used.

Patch by Mihail Popa <Mihail.Popa@arm.com>

llvm-svn: 179398

1 files changed, 11 insertions, 7 deletions

diff --git a/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp b/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
index 2afb20d6686..3bcd083a35f 100644
--- a/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
+++ b/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
@@ -490,7 +490,8 @@ void ARMInstPrinter::printAM3PostIndexOp(const MCInst *MI, unsigned Op,
 }
 
 void ARMInstPrinter::printAM3PreOrOffsetIndexOp(const MCInst *MI, unsigned Op,
-                                                raw_ostream &O) {
+                                                raw_ostream &O,
+                                                bool AlwaysPrintImm0) {
   const MCOperand &MO1 = MI->getOperand(Op);
   const MCOperand &MO2 = MI->getOperand(Op+1);
   const MCOperand &MO3 = MI->getOperand(Op+2);
@@ -509,7 +510,7 @@ void ARMInstPrinter::printAM3PreOrOffsetIndexOp(const MCInst *MI, unsigned Op,
   unsigned ImmOffs = ARM_AM::getAM3Offset(MO3.getImm());
   ARM_AM::AddrOpc op = ARM_AM::getAM3Op(MO3.getImm());
 
-  if (ImmOffs || (op == ARM_AM::sub)) {
+  if (AlwaysPrintImm0 || ImmOffs || (op == ARM_AM::sub)) {
     O << ", "
       << markup("<imm:")
       << "#"
@@ -520,6 +521,7 @@ void ARMInstPrinter::printAM3PreOrOffsetIndexOp(const MCInst *MI, unsigned Op,
   O << ']' << markup(">");
 }
 
+template <bool AlwaysPrintImm0>
 void ARMInstPrinter::printAddrMode3Operand(const MCInst *MI, unsigned Op,
                                            raw_ostream &O) {
   const MCOperand &MO1 = MI->getOperand(Op);
@@ -535,7 +537,7 @@ void ARMInstPrinter::printAddrMode3Operand(const MCInst *MI, unsigned Op,
     printAM3PostIndexOp(MI, Op, O);
     return;
   }
-  printAM3PreOrOffsetIndexOp(MI, Op, O);
+  printAM3PreOrOffsetIndexOp(MI, Op, O, AlwaysPrintImm0);
 }
 
 void ARMInstPrinter::printAddrMode3OffsetOperand(const MCInst *MI,
@@ -593,6 +595,7 @@ void ARMInstPrinter::printLdStmModeOperand(const MCInst *MI, unsigned OpNum,
   O << ARM_AM::getAMSubModeStr(Mode);
 }
 
+template <bool AlwaysPrintImm0>
 void ARMInstPrinter::printAddrMode5Operand(const MCInst *MI, unsigned OpNum,
                                            raw_ostream &O) {
   const MCOperand &MO1 = MI->getOperand(OpNum);
@@ -608,7 +611,7 @@ void ARMInstPrinter::printAddrMode5Operand(const MCInst *MI, unsigned OpNum,
 
   unsigned ImmOffs = ARM_AM::getAM5Offset(MO2.getImm());
   unsigned Op = ARM_AM::getAM5Op(MO2.getImm());
-  if (ImmOffs || Op == ARM_AM::sub) {
+  if (AlwaysPrintImm0 || ImmOffs || Op == ARM_AM::sub) {
     O << ", "
       << markup("<imm:")
       << "#"
@@ -1022,6 +1025,7 @@ void ARMInstPrinter::printT2SOOperand(const MCInst *MI, unsigned OpNum,
                    ARM_AM::getSORegOffset(MO2.getImm()), UseMarkup);
 }
 
+template <bool AlwaysPrintImm0>
 void ARMInstPrinter::printAddrModeImm12Operand(const MCInst *MI, unsigned OpNum,
                                                raw_ostream &O) {
   const MCOperand &MO1 = MI->getOperand(OpNum);
@@ -1042,13 +1046,13 @@ void ARMInstPrinter::printAddrModeImm12Operand(const MCInst *MI, unsigned OpNum,
     OffImm = 0;
   if (isSub) {
     O << ", "
-      << markup("<imm:") 
+      << markup("<imm:")
       << "#-" << -OffImm
       << markup(">");
   }
-  else if (OffImm > 0) {
+  else if (AlwaysPrintImm0 || OffImm > 0) {
     O << ", "
-      << markup("<imm:") 
+      << markup("<imm:")
       << "#" << OffImm
       << markup(">");
   }