Fix thumb2 lifting to prevent temp reg spillover for post dec stm instruction.

bpotchik · bpotchik · commit cbf39e0505c4 · 2025-07-02T16:16:19.000-04:00
diff --git a/arch/armv7/thumb2_disasm/il_thumb2.cpp b/arch/armv7/thumb2_disasm/il_thumb2.cpp
@@ -1474,12 +1474,13 @@ bool GetLowLevelILForThumbInstruction(Architecture* arch, LowLevelILFunction& il
 		else
 			il.AddInstruction(il.SetRegister(4, LLIL_TEMP(0), il.Register(4, baseReg)));
 
+		uint32_t targetReg = decBeforeMode ? LLIL_TEMP(0) : baseReg;
 		for (int32_t i = 0, slot = 0; i <= regLimit; i++)
 		{
 			if ((regs >> i) & 1)
 			{
 				il.AddInstruction(il.Store(4,
-					il.Add(4, il.Register(4, LLIL_TEMP(0)), il.Const(4, 4 * slot++)),
+					il.Add(4, il.Register(4, targetReg), il.Const(4, 4 * slot++)),
 						il.Register(4, GetRegisterByIndex(i))));
 			}
 		}

Original file line number	Diff line number	Diff line change
`@@ -1474,12 +1474,13 @@ bool GetLowLevelILForThumbInstruction(Architecture* arch, LowLevelILFunction& il`
`1474`	`1474`	`else`
`1475`	`1475`	`il.AddInstruction(il.SetRegister(4, LLIL_TEMP(0), il.Register(4, baseReg)));`
`1476`	`1476`
	`1477`	`+ uint32_t targetReg = decBeforeMode ? LLIL_TEMP(0) : baseReg;`
`1477`	`1478`	`for (int32_t i = 0, slot = 0; i <= regLimit; i++)`
`1478`	`1479`	`{`
`1479`	`1480`	`if ((regs >> i) & 1)`
`1480`	`1481`	`{`
`1481`	`1482`	`il.AddInstruction(il.Store(4,`
`1482`		`- il.Add(4, il.Register(4, LLIL_TEMP(0)), il.Const(4, 4 * slot++)),`
	`1483`	`+ il.Add(4, il.Register(4, targetReg), il.Const(4, 4 * slot++)),`
`1483`	`1484`	`il.Register(4, GetRegisterByIndex(i))));`
`1484`	`1485`	`}`
`1485`	`1486`	`}`