[llvm] r211533 - Fix PR20056: Implement pseudo LDR <reg>, =<literal/label> for AArch64
Weiming Zhao
weimingz at codeaurora.org
Mon Jun 23 13:44:17 PDT 2014
Author: weimingz
Date: Mon Jun 23 15:44:16 2014
New Revision: 211533
URL: http://llvm.org/viewvc/llvm-project?rev=211533&view=rev
Log:
Fix PR20056: Implement pseudo LDR <reg>, =<literal/label> for AArch64
This patch is based on the changes from ARM target [1,2]
Based on ARM doc [3], if the literal value can be loaded with a valid MOV,
it can emit that instruction. This is implemented in this patch.
[1] Fix PR18345: ldr= pseudo instruction produces incorrect code when using in inline assembly
Author: David Peixotto <dpeixott at codeaurora.org>
commit b92cca222898d87bbc764fa22e805adb04ef7f13 (r200777)
[2] Implement the ldr-pseudo opcode for ARM assembly
Author: David Peixotto <dpeixott at codeaurora.org>
commit 0fa193b08627927ccaa0804a34d80480894614b8 (r197708)
[3] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0802a/CJAHAIBC.html
Differential Revision: http://reviews.llvm.org/D4163
Modified:
llvm/trunk/include/llvm/MC/MCStreamer.h
llvm/trunk/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
llvm/trunk/lib/Target/AArch64/MCTargetDesc/CMakeLists.txt
Modified: llvm/trunk/include/llvm/MC/MCStreamer.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCStreamer.h?rev=211533&r1=211532&r2=211533&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCStreamer.h (original)
+++ llvm/trunk/include/llvm/MC/MCStreamer.h Mon Jun 23 15:44:16 2014
@@ -86,6 +86,27 @@ public:
virtual void finish();
};
+class AArch64TargetStreamer : public MCTargetStreamer {
+public:
+ AArch64TargetStreamer(MCStreamer &S);
+ ~AArch64TargetStreamer();
+
+
+ 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 *);
+
+ /// Callback used to implemnt the .ltorg directive.
+ /// Emit contents of constant pool for the current section.
+ void emitCurrentConstantPool();
+
+private:
+ std::unique_ptr<AssemblerConstantPools> ConstantPools;
+};
+
// FIXME: declared here because it is used from
// lib/CodeGen/AsmPrinter/ARMException.cpp.
class ARMTargetStreamer : public MCTargetStreamer {
Modified: llvm/trunk/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp?rev=211533&r1=211532&r2=211533&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp Mon Jun 23 15:44:16 2014
@@ -43,6 +43,11 @@ private:
MCSubtargetInfo &STI;
MCAsmParser &Parser;
+ AArch64TargetStreamer &getTargetStreamer() {
+ MCTargetStreamer &TS = *getParser().getStreamer().getTargetStreamer();
+ return static_cast<AArch64TargetStreamer &>(TS);
+ }
+
MCAsmParser &getParser() const { return Parser; }
MCAsmLexer &getLexer() const { return Parser.getLexer(); }
@@ -67,6 +72,7 @@ private:
bool parseDirectiveTLSDescCall(SMLoc L);
bool parseDirectiveLOH(StringRef LOH, SMLoc L);
+ bool parseDirectiveLtorg(SMLoc L);
bool validateInstruction(MCInst &Inst, SmallVectorImpl<SMLoc> &Loc);
bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
@@ -105,6 +111,8 @@ public:
const MCTargetOptions &Options)
: MCTargetAsmParser(), STI(_STI), Parser(_Parser) {
MCAsmParserExtension::Initialize(_Parser);
+ if (Parser.getStreamer().getTargetStreamer() == nullptr)
+ new AArch64TargetStreamer(Parser.getStreamer());
// Initialize the set of available features.
setAvailableFeatures(ComputeAvailableFeatures(STI.getFeatureBits()));
@@ -3004,6 +3012,43 @@ bool AArch64AsmParser::parseOperand(Oper
Operands.push_back(AArch64Operand::CreateImm(ImmVal, S, E, getContext()));
return false;
}
+ case AsmToken::Equal: {
+ SMLoc Loc = Parser.getTok().getLoc();
+ if (Mnemonic != "ldr") // only parse for ldr pseudo (e.g. ldr r0, =val)
+ return Error(Loc, "unexpected token in operand");
+ Parser.Lex(); // Eat '='
+ const MCExpr *SubExprVal;
+ if (getParser().parseExpression(SubExprVal))
+ return true;
+
+ MCContext& Ctx = getContext();
+ E = SMLoc::getFromPointer(Loc.getPointer() - 1);
+ // If the op is an imm and can be fit into a mov, then replace ldr with mov.
+ if (isa<MCConstantExpr>(SubExprVal) && Operands.size() >= 2 &&
+ static_cast<AArch64Operand &>(*Operands[1]).isReg()) {
+ bool IsXReg = AArch64MCRegisterClasses[AArch64::GPR64allRegClassID].contains(
+ Operands[1]->getReg());
+ uint64_t Imm = (cast<MCConstantExpr>(SubExprVal))->getValue();
+ uint32_t ShiftAmt = 0, MaxShiftAmt = IsXReg ? 48 : 16;
+ while(Imm > 0xFFFF && countTrailingZeros(Imm) >= 16) {
+ ShiftAmt += 16;
+ Imm >>= 16;
+ }
+ if (ShiftAmt <= MaxShiftAmt && Imm <= 0xFFFF) {
+ Operands[0] = AArch64Operand::CreateToken("movz", false, Loc, Ctx);
+ Operands.push_back(AArch64Operand::CreateImm(
+ MCConstantExpr::Create(Imm, Ctx), S, E, Ctx));
+ if (ShiftAmt)
+ Operands.push_back(AArch64Operand::CreateShiftExtend(AArch64_AM::LSL,
+ ShiftAmt, true, S, E, Ctx));
+ return false;
+ }
+ }
+ // If it is a label or an imm that cannot fit in a movz, put it into CP.
+ const MCExpr *CPLoc = getTargetStreamer().addConstantPoolEntry(SubExprVal);
+ Operands.push_back(AArch64Operand::CreateImm(CPLoc, S, E, Ctx));
+ return false;
+ }
}
}
@@ -3810,7 +3855,8 @@ bool AArch64AsmParser::ParseDirective(As
return parseDirectiveWord(8, Loc);
if (IDVal == ".tlsdesccall")
return parseDirectiveTLSDescCall(Loc);
-
+ if (IDVal == ".ltorg" || IDVal == ".pool")
+ return parseDirectiveLtorg(Loc);
return parseDirectiveLOH(IDVal, Loc);
}
@@ -3911,6 +3957,13 @@ bool AArch64AsmParser::parseDirectiveLOH
return false;
}
+/// parseDirectiveLtorg
+/// ::= .ltorg | .pool
+bool AArch64AsmParser::parseDirectiveLtorg(SMLoc L) {
+ getTargetStreamer().emitCurrentConstantPool();
+ return false;
+}
+
bool
AArch64AsmParser::classifySymbolRef(const MCExpr *Expr,
AArch64MCExpr::VariantKind &ELFRefKind,
Modified: llvm/trunk/lib/Target/AArch64/MCTargetDesc/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/MCTargetDesc/CMakeLists.txt?rev=211533&r1=211532&r2=211533&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/MCTargetDesc/CMakeLists.txt (original)
+++ llvm/trunk/lib/Target/AArch64/MCTargetDesc/CMakeLists.txt Mon Jun 23 15:44:16 2014
@@ -7,6 +7,7 @@ add_llvm_library(LLVMAArch64Desc
AArch64MCExpr.cpp
AArch64MCTargetDesc.cpp
AArch64MachObjectWriter.cpp
+ AArch64TargetStreamer.cpp
)
add_dependencies(LLVMAArch64Desc AArch64CommonTableGen)
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