vendor/llvm-project/llvmorg-18.1.1-0-gdba2a75e9c7e

1 files changed, 77 insertions, 1 deletions

diff --git a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
index 36aab383da68..9d6e8dc573a8 100644
--- a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -150,6 +150,7 @@ class MipsAsmParser : public MCTargetAsmParser {
   bool IsLittleEndian;
   bool IsPicEnabled;
   bool IsCpRestoreSet;
+  bool CurForbiddenSlotAttr;
   int CpRestoreOffset;
   unsigned GPReg;
   unsigned CpSaveLocation;
@@ -552,6 +553,7 @@ public:
 
     CurrentFn = nullptr;
 
+    CurForbiddenSlotAttr = false;
     IsPicEnabled = getContext().getObjectFileInfo()->isPositionIndependent();
 
     IsCpRestoreSet = false;
@@ -723,6 +725,16 @@ public:
     return getSTI().hasFeature(Mips::FeatureGINV);
   }
 
+  bool hasForbiddenSlot(const MCInstrDesc &MCID) const {
+    return !inMicroMipsMode() && (MCID.TSFlags & MipsII::HasForbiddenSlot);
+  }
+
+  bool SafeInForbiddenSlot(const MCInstrDesc &MCID) const {
+    return !(MCID.TSFlags & MipsII::IsCTI);
+  }
+
+  void onEndOfFile() override;
+
   /// Warn if RegIndex is the same as the current AT.
   void warnIfRegIndexIsAT(unsigned RegIndex, SMLoc Loc);
 
@@ -2307,7 +2319,41 @@ bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
 
   bool FillDelaySlot =
       MCID.hasDelaySlot() && AssemblerOptions.back()->isReorder();
-  if (FillDelaySlot)
+
+  // Get previous instruction`s forbidden slot attribute and
+  // whether set reorder.
+  bool PrevForbiddenSlotAttr = CurForbiddenSlotAttr;
+
+  // Flag represents we set reorder after nop.
+  bool SetReorderAfterNop = false;
+
+  // If previous instruction has forbidden slot and .set reorder
+  // is active and current instruction is CTI.
+  // Then emit a NOP after it.
+  if (PrevForbiddenSlotAttr && !SafeInForbiddenSlot(MCID)) {
+    TOut.emitEmptyDelaySlot(false, IDLoc, STI);
+    // When 'FillDelaySlot' is true, the existing logic will add
+    // noreorder before instruction and reorder after it. So there
+    // need exclude this case avoiding two '.set reorder'.
+    // The format of the first case is:
+    // .set noreorder
+    // bnezc
+    // nop
+    // .set reorder
+    if (AssemblerOptions.back()->isReorder() && !FillDelaySlot) {
+      SetReorderAfterNop = true;
+      TOut.emitDirectiveSetReorder();
+    }
+  }
+
+  // Save current instruction`s forbidden slot and whether set reorder.
+  // This is the judgment condition for whether to add nop.
+  // We would add a couple of '.set noreorder' and '.set reorder' to
+  // wrap the current instruction and the next instruction.
+  CurForbiddenSlotAttr =
+      hasForbiddenSlot(MCID) && AssemblerOptions.back()->isReorder();
+
+  if (FillDelaySlot || CurForbiddenSlotAttr)
     TOut.emitDirectiveSetNoReorder();
 
   MacroExpanderResultTy ExpandResult =
@@ -2322,6 +2368,17 @@ bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
     return true;
   }
 
+  // When current instruction was not CTI, recover reorder state.
+  // The format of the second case is:
+  // .set noreoder
+  // bnezc
+  // add
+  // .set reorder
+  if (PrevForbiddenSlotAttr && !SetReorderAfterNop && !FillDelaySlot &&
+      AssemblerOptions.back()->isReorder()) {
+    TOut.emitDirectiveSetReorder();
+  }
+
   // We know we emitted an instruction on the MER_NotAMacro or MER_Success path.
   // If we're in microMIPS mode then we must also set EF_MIPS_MICROMIPS.
   if (inMicroMipsMode()) {
@@ -2331,6 +2388,14 @@ bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
 
   // If this instruction has a delay slot and .set reorder is active,
   // emit a NOP after it.
+  // The format of the third case is:
+  // .set noreorder
+  // bnezc
+  // nop
+  // .set noreorder
+  // j
+  // nop
+  // .set reorder
   if (FillDelaySlot) {
     TOut.emitEmptyDelaySlot(hasShortDelaySlot(Inst), IDLoc, STI);
     TOut.emitDirectiveSetReorder();
@@ -2356,6 +2421,17 @@ bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
   return false;
 }
 
+void MipsAsmParser::onEndOfFile() {
+  MipsTargetStreamer &TOut = getTargetStreamer();
+  SMLoc IDLoc = SMLoc();
+  // If has pending forbidden slot, fill nop and recover reorder.
+  if (CurForbiddenSlotAttr) {
+    TOut.emitEmptyDelaySlot(false, IDLoc, STI);
+    if (AssemblerOptions.back()->isReorder())
+      TOut.emitDirectiveSetReorder();
+  }
+}
+
 MipsAsmParser::MacroExpanderResultTy
 MipsAsmParser::tryExpandInstruction(MCInst &Inst, SMLoc IDLoc, MCStreamer &Out,
                                     const MCSubtargetInfo *STI) {