[PATCH] D89837: [X86] Error on using h-registers with REX prefix in the assembler instead of leaving it to a fatal error in the encoder.
Craig Topper via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 20 19:31:20 PDT 2020
craig.topper updated this revision to Diff 299541.
craig.topper added a comment.
Skip the REX prefix check if encoding is VEX/EVEX/XOP.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D89837/new/
https://reviews.llvm.org/D89837
Files:
llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
llvm/test/MC/X86/encoder-fail.s
Index: llvm/test/MC/X86/encoder-fail.s
===================================================================
--- llvm/test/MC/X86/encoder-fail.s
+++ llvm/test/MC/X86/encoder-fail.s
@@ -1,3 +1,3 @@
-// RUN: not --crash llvm-mc -triple x86_64-unknown-unknown --show-encoding %s 2>&1 | FileCheck %s
-// CHECK: LLVM ERROR: Cannot encode high byte register in REX-prefixed instruction
+// RUN: not llvm-mc -triple x86_64-unknown-unknown --show-encoding %s 2>&1 | FileCheck %s
+// CHECK: error: can't encode 'dh' in an instruction requiring REX prefix.
movzx %dh, %rsi
Index: llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
===================================================================
--- llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -3619,6 +3619,33 @@
}
}
+ const MCInstrDesc &MCID = MII.get(Inst.getOpcode());
+ // Check that we aren't mixing AH/BH/CH/DH with REX prefix. We only need to
+ // check this with the legacy encoding, VEX/EVEX/XOP don't use REX.
+ if ((MCID.TSFlags & X86II::EncodingMask) == 0) {
+ MCPhysReg HReg = X86::NoRegister;
+ bool UsesRex = MCID.TSFlags & X86II::REX_W;
+ unsigned NumOps = Inst.getNumOperands();
+ for (unsigned i = 0; i != NumOps; ++i) {
+ const MCOperand &MO = Inst.getOperand(i);
+ if (!MO.isReg())
+ continue;
+ unsigned Reg = MO.getReg();
+ if (Reg == X86::AH || Reg == X86::BH || Reg == X86::CH || Reg == X86::DH)
+ HReg = Reg;
+ if (X86II::isX86_64NonExtLowByteReg(Reg) ||
+ X86II::isX86_64ExtendedReg(Reg))
+ UsesRex = true;
+ }
+
+ if (UsesRex && HReg != X86::NoRegister) {
+ StringRef RegName = X86IntelInstPrinter::getRegisterName(HReg);
+ return Error(Ops[0]->getStartLoc(),
+ "can't encode '" + RegName + "' in an instruction requiring "
+ "REX prefix.");
+ }
+ }
+
return false;
}
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