Teach the MC and disassembler about SoftFail, and hook it up to UNPREDICTABLE on ARM. Wire this to tBLX in order to provide test coverage.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150169 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/FixedLenDecoderEmitter.cpp b/utils/TableGen/FixedLenDecoderEmitter.cpp
index c0a0a80..e0d9eb5 100644
--- a/utils/TableGen/FixedLenDecoderEmitter.cpp
+++ b/utils/TableGen/FixedLenDecoderEmitter.cpp
@@ -17,6 +17,7 @@
#include "FixedLenDecoderEmitter.h"
#include "CodeGenTarget.h"
#include "llvm/TableGen/Record.h"
+#include "llvm/ADT/APInt.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
@@ -285,8 +286,19 @@
void insnWithID(insn_t &Insn, unsigned Opcode) const {
BitsInit &Bits = getBitsField(*AllInstructions[Opcode]->TheDef, "Inst");
- for (unsigned i = 0; i < BitWidth; ++i)
- Insn.push_back(bitFromBits(Bits, i));
+ // We may have a SoftFail bitmask, which specifies a mask where an encoding
+ // may differ from the value in "Inst" and yet still be valid, but the
+ // disassembler should return SoftFail instead of Success.
+ //
+ // This is used for marking UNPREDICTABLE instructions in the ARM world.
+ BitsInit *SFBits = AllInstructions[Opcode]->TheDef->getValueAsBitsInit("SoftFail");
+
+ for (unsigned i = 0; i < BitWidth; ++i) {
+ if (SFBits && bitFromBits(*SFBits, i) == BIT_TRUE)
+ Insn.push_back(BIT_UNSET);
+ else
+ Insn.push_back(bitFromBits(Bits, i));
+ }
}
// Returns the record name.
@@ -334,6 +346,8 @@
// Returns true if predicate matches were emitted, false otherwise.
bool emitPredicateMatch(raw_ostream &o, unsigned &Indentation,unsigned Opc);
+ void emitSoftFailCheck(raw_ostream &o, unsigned Indentation, unsigned Opc);
+
// Emits code to decode the singleton. Return true if we have matched all the
// well-known bits.
bool emitSingletonDecoder(raw_ostream &o, unsigned &Indentation,unsigned Opc);
@@ -800,6 +814,64 @@
return Predicates->getSize() > 0;
}
+void FilterChooser::emitSoftFailCheck(raw_ostream &o, unsigned Indentation, unsigned Opc) {
+ BitsInit *SFBits = AllInstructions[Opc]->TheDef->getValueAsBitsInit("SoftFail");
+ if (!SFBits) return;
+ BitsInit *InstBits = AllInstructions[Opc]->TheDef->getValueAsBitsInit("Inst");
+
+ APInt PositiveMask(BitWidth, 0ULL);
+ APInt NegativeMask(BitWidth, 0ULL);
+ for (unsigned i = 0; i < BitWidth; ++i) {
+ bit_value_t B = bitFromBits(*SFBits, i);
+ bit_value_t IB = bitFromBits(*InstBits, i);
+
+ if (B != BIT_TRUE) continue;
+
+ switch (IB) {
+ case BIT_FALSE:
+ // The bit is meant to be false, so emit a check to see if it is true.
+ PositiveMask.setBit(i);
+ break;
+ case BIT_TRUE:
+ // The bit is meant to be true, so emit a check to see if it is false.
+ NegativeMask.setBit(i);
+ break;
+ default:
+ // The bit is not set; this must be an error!
+ StringRef Name = AllInstructions[Opc]->TheDef->getName();
+ errs() << "SoftFail Conflict: bit SoftFail{" << i << "} in "
+ << Name
+ << " is set but Inst{" << i <<"} is unset!\n"
+ << " - You can only mark a bit as SoftFail if it is fully defined"
+ << " (1/0 - not '?') in Inst\n";
+ o << "#error SoftFail Conflict, " << Name << "::SoftFail{" << i
+ << "} set but Inst{" << i << "} undefined!\n";
+ }
+ }
+
+ bool NeedPositiveMask = PositiveMask.getBoolValue();
+ bool NeedNegativeMask = NegativeMask.getBoolValue();
+
+ if (!NeedPositiveMask && !NeedNegativeMask)
+ return;
+
+ std::string PositiveMaskStr = PositiveMask.toString(16, /*signed=*/false);
+ std::string NegativeMaskStr = NegativeMask.toString(16, /*signed=*/false);
+ StringRef BitExt = "";
+ if (BitWidth > 32)
+ BitExt = "ULL";
+
+ o.indent(Indentation) << "if (";
+ if (NeedPositiveMask)
+ o << "insn & 0x" << PositiveMaskStr << BitExt;
+ if (NeedPositiveMask && NeedNegativeMask)
+ o << " || ";
+ if (NeedNegativeMask)
+ o << "~insn & 0x" << NegativeMaskStr << BitExt;
+ o << ")\n";
+ o.indent(Indentation+2) << "S = MCDisassembler::SoftFail;\n";
+}
+
// Emits code to decode the singleton. Return true if we have matched all the
// well-known bits.
bool FilterChooser::emitSingletonDecoder(raw_ostream &o, unsigned &Indentation,
@@ -822,6 +894,7 @@
if (!emitPredicateMatch(o, Indentation, Opc))
o << "1";
o << ") {\n";
+ emitSoftFailCheck(o, Indentation+2, Opc);
o.indent(Indentation) << " MI.setOpcode(" << Opc << ");\n";
std::vector<OperandInfo>& InsnOperands = Operands[Opc];
for (std::vector<OperandInfo>::iterator
@@ -871,6 +944,7 @@
else
o << ") {\n";
}
+ emitSoftFailCheck(o, Indentation+2, Opc);
o.indent(Indentation) << " MI.setOpcode(" << Opc << ");\n";
std::vector<OperandInfo>& InsnOperands = Operands[Opc];
for (std::vector<OperandInfo>::iterator