[ARM,AArch64] Store source location of asm constant pool entries

[olista01]

Summary

Storing the source location of the expression that created a constant pool entry allows us to emit better error messages if we later discover that the expression cannot be represented by a relocation.

[rengolin]

LGTM, thanks!

[grosbach]

Very nice. Thank you!

include/llvm/MC/ConstantPools.h

 //===----------------------------------------------------------------------===//
 
 
 #ifndef LLVM_MC_CONSTANTPOOLS_H
 #define LLVM_MC_CONSTANTPOOLS_H
 
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/SMLoc.h"
 
 namespace llvm {
 class MCContext;
 class MCExpr;
 class MCSection;
 class MCStreamer;
 class MCSymbol;
 
 struct ConstantPoolEntry {
-  ConstantPoolEntry(MCSymbol *L, const MCExpr *Val, unsigned Sz)
-    : Label(L), Value(Val), Size(Sz) {}
+  ConstantPoolEntry(MCSymbol *L, const MCExpr *Val, unsigned Sz, SMLoc Loc_)
+    : Label(L), Value(Val), Size(Sz), Loc(Loc_) {}
   MCSymbol *Label;
   const MCExpr *Value;
   unsigned Size;
+  SMLoc Loc;
 };
 
 // A class to keep track of assembler-generated constant pools that are use to
 // implement the ldr-pseudo.
 class ConstantPool {
   typedef SmallVector<ConstantPoolEntry, 4> EntryVecTy;
   EntryVecTy Entries;
 
 public:
   // Initialize a new empty constant pool
   ConstantPool() {}
 
   // Add a new entry to the constant pool in the next slot.
   // \param Value is the new entry to put in the constant pool.
   // \param Size is the size in bytes of the entry
   //
   // \returns a MCExpr that references the newly inserted value
   const MCExpr *addEntry(const MCExpr *Value, MCContext &Context,
-                         unsigned Size);
+                         unsigned Size, SMLoc Loc);
 
   // Emit the contents of the constant pool using the provided streamer.
   void emitEntries(MCStreamer &Streamer);
 
   // Return true if the constant pool is empty
   bool empty();
 };
 
class AssemblerConstantPools {
   // file.
   typedef MapVector<MCSection *, ConstantPool> ConstantPoolMapTy;
   ConstantPoolMapTy ConstantPools;
 
 public:
   void emitAll(MCStreamer &Streamer);
   void emitForCurrentSection(MCStreamer &Streamer);
   const MCExpr *addEntry(MCStreamer &Streamer, const MCExpr *Expr,
-                         unsigned Size);
+                         unsigned Size, SMLoc Loc);
 
 private:
   ConstantPool *getConstantPool(MCSection *Section);
   ConstantPool &getOrCreateConstantPool(MCSection *Section);
 };
 } // end namespace llvm
 
 #endif

include/llvm/MC/MCStreamer.h

public:
 
   virtual void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value);
 
   void finish() override;
 
   /// Callback used to implement the ldr= pseudo.
   /// Add a new entry to the constant pool for the current section and return an
   /// MCExpr that can be used to refer to the constant pool location.
-  const MCExpr *addConstantPoolEntry(const MCExpr *);
+  const MCExpr *addConstantPoolEntry(const MCExpr *, SMLoc Loc);
 
   /// Callback used to implemnt the .ltorg directive.
   /// Emit contents of constant pool for the current section.
   void emitCurrentConstantPool();
 
 private:
   std::unique_ptr<AssemblerConstantPools> ConstantPools;
 };

lib/MC/ConstantPools.cpp

 void ConstantPool::emitEntries(MCStreamer &Streamer) {
   if (Entries.empty())
     return;
   Streamer.EmitDataRegion(MCDR_DataRegion);
   for (EntryVecTy::const_iterator I = Entries.begin(), E = Entries.end();
        I != E; ++I) {
     Streamer.EmitCodeAlignment(I->Size); // align naturally
     Streamer.EmitLabel(I->Label);
-    Streamer.EmitValue(I->Value, I->Size);
+    Streamer.EmitValue(I->Value, I->Size, I->Loc);
   }
   Streamer.EmitDataRegion(MCDR_DataRegionEnd);
   Entries.clear();
 }
 
 const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context,
-                                     unsigned Size) {
+                                     unsigned Size, SMLoc Loc) {
   MCSymbol *CPEntryLabel = Context.createTempSymbol();
 
-  Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size));
+  Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size, Loc));
   return MCSymbolRefExpr::create(CPEntryLabel, Context);
 }
 
 bool ConstantPool::empty() { return Entries.empty(); }
 
 //
 // AssemblerConstantPools implementation
 //
void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
   MCSection *Section = Streamer.getCurrentSection().first;
   if (ConstantPool *CP = getConstantPool(Section)) {
     emitConstantPool(Streamer, Section, *CP);
   }
 }
 
 const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
                                                const MCExpr *Expr,
-                                               unsigned Size) {
+                                               unsigned Size, SMLoc Loc) {
   MCSection *Section = Streamer.getCurrentSection().first;
   return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext(),
-                                                   Size);
+                                                   Size, Loc);
 }

lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp

if (isa<MCConstantExpr>(SubExprVal)) {
       }
       APInt Simm = APInt(64, Imm << ShiftAmt);
       // check if the immediate is an unsigned or signed 32-bit int for W regs
       if (!IsXReg && !(Simm.isIntN(32) || Simm.isSignedIntN(32)))
         return Error(Loc, "Immediate too large for register");
     }
     // If it is a label or an imm that cannot fit in a movz, put it into CP.
     const MCExpr *CPLoc =
-        getTargetStreamer().addConstantPoolEntry(SubExprVal, IsXReg ? 8 : 4);
+        getTargetStreamer().addConstantPoolEntry(SubExprVal, IsXReg ? 8 : 4, Loc);
     Operands.push_back(AArch64Operand::CreateImm(CPLoc, S, E, Ctx));
     return false;
   }
   }
 }
 
 /// ParseInstruction - Parse an AArch64 instruction mnemonic followed by its
 /// operands.

lib/Target/AArch64/MCTargetDesc/AArch64TargetStreamer.h

public:
   AArch64TargetStreamer(MCStreamer &S);
   ~AArch64TargetStreamer() override;
 
   void finish() override;
 
   /// Callback used to implement the ldr= pseudo.
   /// Add a new entry to the constant pool for the current section and return an
   /// MCExpr that can be used to refer to the constant pool location.
-  const MCExpr *addConstantPoolEntry(const MCExpr *, unsigned Size);
+  const MCExpr *addConstantPoolEntry(const MCExpr *, unsigned Size, SMLoc Loc);
 
   /// Callback used to implemnt the .ltorg directive.
   /// Emit contents of constant pool for the current section.
   void emitCurrentConstantPool();
 
   /// Callback used to implement the .inst directive.
   virtual void emitInst(uint32_t Inst);
 
 private:
   std::unique_ptr<AssemblerConstantPools> ConstantPools;
 };
 
 } // end namespace llvm
 
 #endif

lib/Target/AArch64/MCTargetDesc/AArch64TargetStreamer.cpp

 AArch64TargetStreamer::AArch64TargetStreamer(MCStreamer &S)
     : MCTargetStreamer(S), ConstantPools(new AssemblerConstantPools()) {}
 
 AArch64TargetStreamer::~AArch64TargetStreamer() {}
 
 // The constant pool handling is shared by all AArch64TargetStreamer
 // implementations.
 const MCExpr *AArch64TargetStreamer::addConstantPoolEntry(const MCExpr *Expr,
-                                                          unsigned Size) {
-  return ConstantPools->addEntry(Streamer, Expr, Size);
+                                                          unsigned Size,
+                                                          SMLoc Loc) {
+  return ConstantPools->addEntry(Streamer, Expr, Size, Loc);
 }
 
 void AArch64TargetStreamer::emitCurrentConstantPool() {
   ConstantPools->emitForCurrentSection(Streamer);
 }
 
 // finish() - write out any non-empty assembler constant pools.
 void AArch64TargetStreamer::finish() { ConstantPools->emitAll(Streamer); }
 
 void AArch64TargetStreamer::emitInst(uint32_t Inst) {}

lib/Target/ARM/AsmParser/ARMAsmParser.cpp

if (Parser.getTok().isNot(AsmToken::Colon)) {
         Parser.Lex(); // Eat exclaim token
       }
       return false;
     }
     // w/ a ':' after the '#', it's just like a plain ':'.
     // FALLTHROUGH
   }
   case AsmToken::Colon: {
+    S = Parser.getTok().getLoc();
     // ":lower16:" and ":upper16:" expression prefixes
     // FIXME: Check it's an expression prefix,
     // e.g. (FOO - :lower16:BAR) isn't legal.
     ARMMCExpr::VariantKind RefKind;
     if (parsePrefix(RefKind))
       return true;
 
     const MCExpr *SubExprVal;
     if (getParser().parseExpression(SubExprVal))
       return true;
 
     const MCExpr *ExprVal = ARMMCExpr::create(RefKind, SubExprVal,
                                               getContext());
     E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
     Operands.push_back(ARMOperand::CreateImm(ExprVal, S, E));
     return false;
   }
   case AsmToken::Equal: {
+    S = Parser.getTok().getLoc();
     if (Mnemonic != "ldr") // only parse for ldr pseudo (e.g. ldr r0, =val)
-      return Error(Parser.getTok().getLoc(), "unexpected token in operand");
+      return Error(S, "unexpected token in operand");
 
     Parser.Lex(); // Eat '='
     const MCExpr *SubExprVal;
     if (getParser().parseExpression(SubExprVal))
       return true;
     E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
 
-    const MCExpr *CPLoc = getTargetStreamer().addConstantPoolEntry(SubExprVal);
+    const MCExpr *CPLoc =
+        getTargetStreamer().addConstantPoolEntry(SubExprVal, S);
     Operands.push_back(ARMOperand::CreateImm(CPLoc, S, E));
     return false;
   }
   }
 }
 
 // parsePrefix - Parse ARM 16-bit relocations expression prefix, i.e.
 //  :lower16: and :upper16:.

lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp

 //
 ARMTargetStreamer::ARMTargetStreamer(MCStreamer &S)
     : MCTargetStreamer(S), ConstantPools(new AssemblerConstantPools()) {}
 
 ARMTargetStreamer::~ARMTargetStreamer() {}
 
 // The constant pool handling is shared by all ARMTargetStreamer
 // implementations.
-const MCExpr *ARMTargetStreamer::addConstantPoolEntry(const MCExpr *Expr) {
-  return ConstantPools->addEntry(Streamer, Expr, 4);
+const MCExpr *ARMTargetStreamer::addConstantPoolEntry(const MCExpr *Expr, SMLoc Loc) {
+  return ConstantPools->addEntry(Streamer, Expr, 4, Loc);
 }
 
 void ARMTargetStreamer::emitCurrentConstantPool() {
   ConstantPools->emitForCurrentSection(Streamer);
 }
 
 // finish() - write out any non-empty assembler constant pools.
 void ARMTargetStreamer::finish() { ConstantPools->emitAll(Streamer); }

test/MC/AArch64/error-location-ldr-pseudo.s

+// RUN: not llvm-mc -triple aarch64--none-eabi -filetype obj < %s -o /dev/null 2>&1 | FileCheck %s
+
+  .text
+// CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: expected relocatable expression
+  ldr x0, =(-undef)

test/MC/ARM/error-location-ldr-pseudo.s

+@ RUN: not llvm-mc -triple armv7a--none-eabi -filetype obj < %s -o /dev/null 2>&1 | FileCheck %s
+
+  .text
+@ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: expected relocatable expression
+  ldr r0, =(-undef)