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Fix the invalid opcode for Mips branch instructions in the assembler 

For mips a branch an 18-bit signed offset (the 16-bit 
offset field shifted left 2 bits) is added to the 
address of the instruction following the branch 
(not the branch itself), in the branch delay slot, 
to form a PC-relative effective target address. 

Previously, the code generator did not perform the 
shift of the immediate branch offset which resulted 
in wrong instruction opcode. This patch fixes the issue.

Contributor: Vladimir Medic
llvm-svn: 177687
This commit is contained in:
Jack Carter 2013-03-22 00:29:10 +00:00
parent 96efb4a442
commit 4f69a0f25d
2 changed files with 18 additions and 16 deletions
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10
llvm/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
View File

@ -160,8 +160,9 @@ getBranchTargetOpValue(const MCInst &MI, unsigned OpNo,
const MCOperand &MO = MI.getOperand(OpNo);
// If the destination is an immediate, we have nothing to do.
if (MO.isImm()) return MO.getImm();
// If the destination is an immediate, divide by 4.
if (MO.isImm()) return MO.getImm() >> 2;
assert(MO.isExpr() &&
"getBranchTargetOpValue expects only expressions or immediates");
@ -179,8 +180,9 @@ getJumpTargetOpValue(const MCInst &MI, unsigned OpNo,
SmallVectorImpl<MCFixup> &Fixups) const {
const MCOperand &MO = MI.getOperand(OpNo);
// If the destination is an immediate, we have nothing to do.
if (MO.isImm()) return MO.getImm();
// If the destination is an immediate, divide by 4.
if (MO.isImm()) return MO.getImm()>>2;
assert(MO.isExpr() &&
"getJumpTargetOpValue expects only expressions or an immediate");

24
llvm/test/MC/Mips/mips-jump-instructions.s
View File

@ -5,25 +5,25 @@
#------------------------------------------------------------------------------
# Branch instructions
#------------------------------------------------------------------------------
# CHECK: b 1332 # encoding: [0x34,0x05,0x00,0x10]
# CHECK: b 1332 # encoding: [0x4d,0x01,0x00,0x10]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: bc1f 1332 # encoding: [0x34,0x05,0x00,0x45]
# CHECK: bc1f 1332 # encoding: [0x4d,0x01,0x00,0x45]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: bc1t 1332 # encoding: [0x34,0x05,0x01,0x45]
# CHECK: bc1t 1332 # encoding: [0x4d,0x01,0x01,0x45]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: beq $9, $6, 1332 # encoding: [0x34,0x05,0x26,0x11]
# CHECK: beq $9, $6, 1332 # encoding: [0x4d,0x01,0x26,0x11]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: bgez $6, 1332 # encoding: [0x34,0x05,0xc1,0x04]
# CHECK: bgez $6, 1332 # encoding: [0x4d,0x01,0xc1,0x04]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: bgezal $6, 1332 # encoding: [0x34,0x05,0xd1,0x04]
# CHECK: bgezal $6, 1332 # encoding: [0x4d,0x01,0xd1,0x04]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: bgtz $6, 1332 # encoding: [0x34,0x05,0xc0,0x1c]
# CHECK: bgtz $6, 1332 # encoding: [0x4d,0x01,0xc0,0x1c]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: blez $6, 1332 # encoding: [0x34,0x05,0xc0,0x18]
# CHECK: blez $6, 1332 # encoding: [0x4d,0x01,0xc0,0x18]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: bne $9, $6, 1332 # encoding: [0x34,0x05,0x26,0x15]
# CHECK: bne $9, $6, 1332 # encoding: [0x4d,0x01,0x26,0x15]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: bal 1332 # encoding: [0x34,0x05,0x11,0x04]
# CHECK: bal 1332 # encoding: [0x4d,0x01,0x11,0x04]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
b 1332
nop
@ -50,9 +50,9 @@ end_of_code:
#------------------------------------------------------------------------------
# Jump instructions
#------------------------------------------------------------------------------
# CHECK: j 1328 # encoding: [0x30,0x05,0x00,0x08]
# CHECK: j 1328 # encoding: [0x4c,0x01,0x00,0x08]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: jal 1328 # encoding: [0x30,0x05,0x00,0x0c]
# CHECK: jal 1328 # encoding: [0x4c,0x01,0x00,0x0c]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]
# CHECK: jalr $6 # encoding: [0x09,0xf8,0xc0,0x00]
# CHECK: nop # encoding: [0x00,0x00,0x00,0x00]