[MC] Fix memory leak when allocating MCInst with bump allocator

Adds the function createMCInst() to MCContext that creates a MCInst using
a typed bump alloctor.

MCInst contains a SmallVector<MCOperand, 8>. The SmallVector is POD only
for <= 8 operands. The default untyped bump pointer allocator of MCContext
does not delete the MCInst, so if the SmallVector grows, it's a leak.

This fixes https://bugs.llvm.org/show_bug.cgi?id=46900.

diff --git a/llvm/include/llvm/MC/MCContext.h b/llvm/include/llvm/MC/MCContext.h
index 45be9bb..d041b06 100644 (file)
--- a/llvm/include/llvm/MC/MCContext.h
+++ b/llvm/include/llvm/MC/MCContext.h
@@ -97,6 +97,7 @@ namespace llvm {
     SpecificBumpPtrAllocator<MCSectionMachO> MachOAllocator;
     SpecificBumpPtrAllocator<MCSectionWasm> WasmAllocator;
     SpecificBumpPtrAllocator<MCSectionXCOFF> XCOFFAllocator;
+    SpecificBumpPtrAllocator<MCInst> MCInstAllocator;
 
     /// Bindings of names to symbols.
     SymbolTable Symbols;
@@ -380,6 +381,11 @@ namespace llvm {
 
     /// @}
 
+    /// \name McInst Management
+
+    /// Create and return a new MC instruction.
+    MCInst *createMCInst();
+
     /// \name Symbol Management
     /// @{
 

diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index a0f9212..5b00789 100644 (file)
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -90,6 +90,7 @@ void MCContext::reset() {
   ELFAllocator.DestroyAll();
   MachOAllocator.DestroyAll();
   XCOFFAllocator.DestroyAll();
+  MCInstAllocator.DestroyAll();
 
   MCSubtargetAllocator.DestroyAll();
   InlineAsmUsedLabelNames.clear();
@@ -127,6 +128,14 @@ void MCContext::reset() {
 }
 
 //===----------------------------------------------------------------------===//
+// MCInst Management
+//===----------------------------------------------------------------------===//
+
+MCInst *MCContext::createMCInst() {
+  return new (MCInstAllocator.Allocate()) MCInst;
+}
+
+//===----------------------------------------------------------------------===//
 // Symbol Manipulation
 //===----------------------------------------------------------------------===//
 

diff --git a/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp b/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
index 1e7862c..3759962 100644 (file)
--- a/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
+++ b/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
@@ -641,7 +641,7 @@ bool HexagonAsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
       return true;
     return finishBundle(IDLoc, Out);
   }
-  MCInst *SubInst = new (getParser().getContext()) MCInst;
+  MCInst *SubInst = getParser().getContext().createMCInst();
   if (matchOneInstruction(*SubInst, IDLoc, Operands, ErrorInfo,
                           MatchingInlineAsm)) {
     if (InBrackets)

diff --git a/llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp b/llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp
index f3a87ef..aeaeac6 100644 (file)
--- a/llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp
+++ b/llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp
@@ -175,7 +175,7 @@ DecodeStatus HexagonDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
   while (Result == Success && !Complete) {
     if (Bytes.size() < HEXAGON_INSTR_SIZE)
       return MCDisassembler::Fail;
-    MCInst *Inst = new (getContext()) MCInst;
+    MCInst *Inst = getContext().createMCInst();
     Result = getSingleInstruction(*Inst, MI, Bytes, Address, cs, Complete);
     MI.addOperand(MCOperand::createInst(Inst));
     Size += HEXAGON_INSTR_SIZE;
@@ -384,8 +384,8 @@ DecodeStatus HexagonDisassembler::getSingleInstruction(MCInst &MI, MCInst &MCB,
       break;
     }
     MI.setOpcode(Hexagon::DuplexIClass0 + duplexIClass);
-    MCInst *MILow = new (getContext()) MCInst;
-    MCInst *MIHigh = new (getContext()) MCInst;
+    MCInst *MILow = getContext().createMCInst();
+    MCInst *MIHigh = getContext().createMCInst();
     auto TmpExtender = CurrentExtender;
     CurrentExtender =
         nullptr; // constant extenders in duplex must always be in slot 1

diff --git a/llvm/lib/Target/Hexagon/HexagonMCInstLower.cpp b/llvm/lib/Target/Hexagon/HexagonMCInstLower.cpp
index 188d913..9507de9 100644 (file)
--- a/llvm/lib/Target/Hexagon/HexagonMCInstLower.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonMCInstLower.cpp
@@ -104,7 +104,7 @@ void llvm::HexagonLowerToMC(const MCInstrInfo &MCII, const MachineInstr *MI,
     HexagonMCInstrInfo::setOuterLoop(MCB);
     return;
   }
-  MCInst *MCI = new (AP.OutContext) MCInst;
+  MCInst *MCI = AP.OutContext.createMCInst();
   MCI->setOpcode(MI->getOpcode());
   assert(MCI->getOpcode() == static_cast<unsigned>(MI->getOpcode()) &&
          "MCI opcode should have been set on construction");

diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
index e706981..627c53c 100644 (file)
--- a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
+++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
@@ -74,7 +74,7 @@ public:
 
   void setExtender(MCContext &Context) const {
     if (Extender == nullptr)
-      const_cast<HexagonAsmBackend *>(this)->Extender = new (Context) MCInst;
+      const_cast<HexagonAsmBackend *>(this)->Extender = Context.createMCInst();
   }
 
   MCInst *takeExtender() const {
@@ -736,7 +736,7 @@ public:
               auto &Inst = const_cast<MCInst &>(RF.getInst());
               while (Size > 0 &&
                      HexagonMCInstrInfo::bundleSize(Inst) < MaxPacketSize) {
-                MCInst *Nop = new (Context) MCInst;
+                MCInst *Nop = Context.createMCInst();
                 Nop->setOpcode(Hexagon::A2_nop);
                 Inst.addOperand(MCOperand::createInst(Nop));
                 Size -= 4;

diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCCompound.cpp b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCCompound.cpp
index 82b2074..e7ade78 100644 (file)
--- a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCCompound.cpp
+++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCCompound.cpp
@@ -210,7 +210,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
   case Hexagon::A2_tfrsi:
     Rt = L.getOperand(0);
     compoundOpcode = J4_jumpseti;
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
 
     CompoundInsn->addOperand(Rt);
@@ -223,7 +223,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
     Rs = L.getOperand(1);
 
     compoundOpcode = J4_jumpsetr;
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
     CompoundInsn->addOperand(Rt);
     CompoundInsn->addOperand(Rs);
@@ -237,7 +237,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
     Rt = L.getOperand(2);
 
     compoundOpcode = cmpeqBitOpcode[getCompoundOp(R)];
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
     CompoundInsn->addOperand(Rs);
     CompoundInsn->addOperand(Rt);
@@ -250,7 +250,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
     Rt = L.getOperand(2);
 
     compoundOpcode = cmpgtBitOpcode[getCompoundOp(R)];
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
     CompoundInsn->addOperand(Rs);
     CompoundInsn->addOperand(Rt);
@@ -263,7 +263,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
     Rt = L.getOperand(2);
 
     compoundOpcode = cmpgtuBitOpcode[getCompoundOp(R)];
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
     CompoundInsn->addOperand(Rs);
     CompoundInsn->addOperand(Rt);
@@ -281,7 +281,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
       compoundOpcode = cmpeqiBitOpcode[getCompoundOp(R)];
 
     Rs = L.getOperand(1);
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
     CompoundInsn->addOperand(Rs);
     CompoundInsn->addOperand(L.getOperand(2));
@@ -299,7 +299,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
       compoundOpcode = cmpgtiBitOpcode[getCompoundOp(R)];
 
     Rs = L.getOperand(1);
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
     CompoundInsn->addOperand(Rs);
     CompoundInsn->addOperand(L.getOperand(2));
@@ -310,7 +310,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
     LLVM_DEBUG(dbgs() << "CX: C2_cmpgtui\n");
     Rs = L.getOperand(1);
     compoundOpcode = cmpgtuiBitOpcode[getCompoundOp(R)];
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
     CompoundInsn->addOperand(Rs);
     CompoundInsn->addOperand(L.getOperand(2));
@@ -321,7 +321,7 @@ static MCInst *getCompoundInsn(MCContext &Context, MCInst const &L,
     LLVM_DEBUG(dbgs() << "CX: S2_tstbit_i\n");
     Rs = L.getOperand(1);
     compoundOpcode = tstBitOpcode[getCompoundOp(R)];
-    CompoundInsn = new (Context) MCInst;
+    CompoundInsn = Context.createMCInst();
     CompoundInsn->setOpcode(compoundOpcode);
     CompoundInsn->addOperand(Rs);
     CompoundInsn->addOperand(R.getOperand(1));