[llvm] r271028 - [MC] Support symbolic expressions in assembly directives
Richard Smith via llvm-commits
llvm-commits at lists.llvm.org
Fri May 27 13:01:49 PDT 2016
On Fri, May 27, 2016 at 11:49 AM, Petr Hosek via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Author: phosek
> Date: Fri May 27 13:49:44 2016
> New Revision: 271028
>
> URL: http://llvm.org/viewvc/llvm-project?rev=271028&view=rev
> Log:
> [MC] Support symbolic expressions in assembly directives
>
> This matches the behavior of GNU assembler which supports symbolic
> expressions in absolute expressions used in assembly directives.
>
> Differential Revision: http://reviews.llvm.org/D20656
>
> Added:
> llvm/trunk/test/MC/AsmParser/symbolic-expression.s
> Modified:
> llvm/trunk/include/llvm/MC/MCObjectStreamer.h
> llvm/trunk/include/llvm/MC/MCStreamer.h
> llvm/trunk/lib/MC/MCAsmStreamer.cpp
> llvm/trunk/lib/MC/MCObjectStreamer.cpp
> llvm/trunk/lib/MC/MCParser/AsmParser.cpp
> llvm/trunk/lib/MC/MCStreamer.cpp
> llvm/trunk/test/MC/AsmParser/directive_fill.s
> llvm/trunk/test/MC/AsmParser/directive_space.s
>
> Modified: llvm/trunk/include/llvm/MC/MCObjectStreamer.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCObjectStreamer.h?rev=271028&r1=271027&r2=271028&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/MC/MCObjectStreamer.h (original)
> +++ llvm/trunk/include/llvm/MC/MCObjectStreamer.h Fri May 27 13:49:44 2016
> @@ -141,6 +141,11 @@ public:
> bool EmitRelocDirective(const MCExpr &Offset, StringRef Name,
> const MCExpr *Expr, SMLoc Loc) override;
> void EmitFill(uint64_t NumBytes, uint8_t FillValue) override;
> + void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
> + SMLoc Loc = SMLoc()) override;
> + void emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
> + SMLoc Loc = SMLoc()) override;
> +
> void FinishImpl() override;
>
> /// Emit the absolute difference between two symbols if possible.
>
> Modified: llvm/trunk/include/llvm/MC/MCStreamer.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCStreamer.h?rev=271028&r1=271027&r2=271028&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/MC/MCStreamer.h (original)
> +++ llvm/trunk/include/llvm/MC/MCStreamer.h Fri May 27 13:49:44 2016
> @@ -577,6 +577,28 @@ public:
> /// This implements directives such as '.space'.
> virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue);
>
> + /// \brief Emit \p Size bytes worth of the value specified by \p
> FillValue.
> + ///
> + /// This is used to implement assembler directives such as .space or
> .skip.
> + ///
> + /// \param NumBytes - The number of bytes to emit.
> + /// \param FillValue - The value to use when filling bytes.
> + /// \param Loc - The location of the expression for error reporting.
> + virtual void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
> + SMLoc Loc = SMLoc());
> +
> + /// \brief Emit \p NumValues copies of \p Size bytes. Each \p Size
> bytes is
> + /// taken from the lowest order 4 bytes of \p Expr expression.
> + ///
> + /// This is used to implement assembler directives such as .fill.
> + ///
> + /// \param NumValues - The number of copies of \p Size bytes to emit.
> + /// \param Size - The size (in bytes) of each repeated value.
> + /// \param Expr - The expression from which \p Size bytes are used.
> + virtual void emitFill(uint64_t NumValues, int64_t Size, int64_t Expr);
> + virtual void emitFill(const MCExpr &NumValues, int64_t Size, int64_t
> Expr,
> + SMLoc Loc = SMLoc());
> +
> /// \brief Emit NumBytes worth of zeros.
> /// This function properly handles data in virtual sections.
> void EmitZeros(uint64_t NumBytes);
>
> Modified: llvm/trunk/lib/MC/MCAsmStreamer.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAsmStreamer.cpp?rev=271028&r1=271027&r2=271028&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/MC/MCAsmStreamer.cpp (original)
> +++ llvm/trunk/lib/MC/MCAsmStreamer.cpp Fri May 27 13:49:44 2016
> @@ -31,6 +31,7 @@
> #include "llvm/Support/LEB128.h"
> #include "llvm/Support/MathExtras.h"
> #include "llvm/Support/Path.h"
> +#include "llvm/Support/SourceMgr.h"
> #include <cctype>
>
> using namespace llvm;
> @@ -178,6 +179,14 @@ public:
>
> void EmitFill(uint64_t NumBytes, uint8_t FillValue) override;
>
> + void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
> + SMLoc Loc = SMLoc()) override;
> +
> + void emitFill(uint64_t NumValues, int64_t Size, int64_t Expr) override;
> +
> + void emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
> + SMLoc Loc = SMLoc()) override;
> +
> void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
> unsigned ValueSize = 1,
> unsigned MaxBytesToEmit = 0) override;
> @@ -799,16 +808,41 @@ void MCAsmStreamer::EmitGPRel32Value(con
> void MCAsmStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue) {
> if (NumBytes == 0) return;
>
> + const MCExpr *E = MCConstantExpr::create(NumBytes, getContext());
> + emitFill(*E, FillValue);
> +}
> +
> +void MCAsmStreamer::emitFill(const MCExpr &NumBytes, uint64_t FillValue,
> + SMLoc Loc) {
> if (const char *ZeroDirective = MAI->getZeroDirective()) {
> - OS << ZeroDirective << NumBytes;
> + // FIXME: Emit location directives
> + OS << ZeroDirective;
> + NumBytes.print(OS, MAI);
> if (FillValue != 0)
> OS << ',' << (int)FillValue;
> EmitEOL();
> return;
> }
>
> - // Emit a byte at a time.
> - MCStreamer::EmitFill(NumBytes, FillValue);
> + MCStreamer::emitFill(NumBytes, FillValue);
> +}
> +
> +void MCAsmStreamer::emitFill(uint64_t NumValues, int64_t Size, int64_t
> Expr) {
> + if (NumValues == 0)
> + return;
> +
> + const MCExpr *E = MCConstantExpr::create(NumValues, getContext());
> + emitFill(*E, Size, Expr);
> +}
> +
> +void MCAsmStreamer::emitFill(const MCExpr &NumValues, int64_t Size,
> + int64_t Expr, SMLoc Loc) {
> + // FIXME: Emit location directives
> + OS << "\t.fill\t";
> + NumValues.print(OS, MAI);
> + OS << ", " << Size << ", 0x";
> + OS.write_hex(truncateToSize(Expr, 32));
>
This makes no sense -- truncateToSize takes a number of bytes. Did you mean
4 here?
This results in undefined behavior every time this function is called, and
causes test/MC/AsmParser/directive_fill.s to fail in optimized bootstraps.
> + EmitEOL();
> }
>
> void MCAsmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t
> Value,
>
> Modified: llvm/trunk/lib/MC/MCObjectStreamer.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectStreamer.cpp?rev=271028&r1=271027&r2=271028&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/MC/MCObjectStreamer.cpp (original)
> +++ llvm/trunk/lib/MC/MCObjectStreamer.cpp Fri May 27 13:49:44 2016
> @@ -20,6 +20,7 @@
> #include "llvm/MC/MCSection.h"
> #include "llvm/MC/MCSymbol.h"
> #include "llvm/Support/ErrorHandling.h"
> +#include "llvm/Support/SourceMgr.h"
> #include "llvm/Support/TargetRegistry.h"
> using namespace llvm;
>
> @@ -496,6 +497,43 @@ void MCObjectStreamer::EmitFill(uint64_t
> insert(new MCFillFragment(FillValue, NumBytes));
> }
>
> +void MCObjectStreamer::emitFill(const MCExpr &NumBytes, uint64_t
> FillValue,
> + SMLoc Loc) {
> + MCDataFragment *DF = getOrCreateDataFragment();
> + flushPendingLabels(DF, DF->getContents().size());
> +
> + int64_t IntNumBytes;
> + if (!NumBytes.evaluateAsAbsolute(IntNumBytes, getAssembler())) {
> + getContext().reportError(Loc, "expected absolute expression");
> + return;
> + }
> +
> + if (IntNumBytes <= 0) {
> + getContext().reportError(Loc, "invalid number of bytes");
> + return;
> + }
> +
> + EmitFill(IntNumBytes, FillValue);
> +}
> +
> +void MCObjectStreamer::emitFill(const MCExpr &NumValues, int64_t Size,
> + int64_t Expr, SMLoc Loc) {
> + int64_t IntNumValues;
> + if (!NumValues.evaluateAsAbsolute(IntNumValues, getAssembler())) {
> + getContext().reportError(Loc, "expected absolute expression");
> + return;
> + }
> +
> + if (IntNumValues < 0) {
> + getContext().getSourceManager()->PrintMessage(
> + Loc, SourceMgr::DK_Warning,
> + "'.fill' directive with negative repeat count has no effect");
> + return;
> + }
> +
> + MCStreamer::emitFill(IntNumValues, Size, Expr);
> +}
> +
> void MCObjectStreamer::FinishImpl() {
> // If we are generating dwarf for assembly source files dump out the
> sections.
> if (getContext().getGenDwarfForAssembly())
>
> Modified: llvm/trunk/lib/MC/MCParser/AsmParser.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/AsmParser.cpp?rev=271028&r1=271027&r2=271028&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/MC/MCParser/AsmParser.cpp (original)
> +++ llvm/trunk/lib/MC/MCParser/AsmParser.cpp Fri May 27 13:49:44 2016
> @@ -2738,8 +2738,9 @@ bool AsmParser::parseDirectiveRealValue(
> bool AsmParser::parseDirectiveZero() {
> checkForValidSection();
>
> - int64_t NumBytes;
> - if (parseAbsoluteExpression(NumBytes))
> + SMLoc NumBytesLoc = Lexer.getLoc();
> + const MCExpr *NumBytes;
> + if (parseExpression(NumBytes))
> return true;
>
> int64_t Val = 0;
> @@ -2754,7 +2755,7 @@ bool AsmParser::parseDirectiveZero() {
>
> Lex();
>
> - getStreamer().EmitFill(NumBytes, Val);
> + getStreamer().emitFill(*NumBytes, Val, NumBytesLoc);
>
> return false;
> }
> @@ -2764,17 +2765,11 @@ bool AsmParser::parseDirectiveZero() {
> bool AsmParser::parseDirectiveFill() {
> checkForValidSection();
>
> - SMLoc RepeatLoc = getLexer().getLoc();
> - int64_t NumValues;
> - if (parseAbsoluteExpression(NumValues))
> + SMLoc NumValuesLoc = Lexer.getLoc();
> + const MCExpr *NumValues;
> + if (parseExpression(NumValues))
> return true;
>
> - if (NumValues < 0) {
> - Warning(RepeatLoc,
> - "'.fill' directive with negative repeat count has no effect");
> - NumValues = 0;
> - }
> -
> int64_t FillSize = 1;
> int64_t FillExpr = 0;
>
> @@ -2806,7 +2801,7 @@ bool AsmParser::parseDirectiveFill() {
>
> if (FillSize < 0) {
> Warning(SizeLoc, "'.fill' directive with negative size has no
> effect");
> - NumValues = 0;
> + NumValues = MCConstantExpr::create(0, getStreamer().getContext());
> }
> if (FillSize > 8) {
> Warning(SizeLoc, "'.fill' directive with size greater than 8 has been
> truncated to 8");
> @@ -2816,15 +2811,7 @@ bool AsmParser::parseDirectiveFill() {
> if (!isUInt<32>(FillExpr) && FillSize > 4)
> Warning(ExprLoc, "'.fill' directive pattern has been truncated to
> 32-bits");
>
> - if (NumValues > 0) {
> - int64_t NonZeroFillSize = FillSize > 4 ? 4 : FillSize;
> - FillExpr &= ~0ULL >> (64 - NonZeroFillSize * 8);
> - for (uint64_t i = 0, e = NumValues; i != e; ++i) {
> - getStreamer().EmitIntValue(FillExpr, NonZeroFillSize);
> - if (NonZeroFillSize < FillSize)
> - getStreamer().EmitIntValue(0, FillSize - NonZeroFillSize);
> - }
> - }
> + getStreamer().emitFill(*NumValues, FillSize, FillExpr, NumValuesLoc);
>
> return false;
> }
> @@ -4057,8 +4044,9 @@ bool AsmParser::parseDirectiveBundleUnlo
> bool AsmParser::parseDirectiveSpace(StringRef IDVal) {
> checkForValidSection();
>
> - int64_t NumBytes;
> - if (parseAbsoluteExpression(NumBytes))
> + SMLoc NumBytesLoc = Lexer.getLoc();
> + const MCExpr *NumBytes;
> + if (parseExpression(NumBytes))
> return true;
>
> int64_t FillExpr = 0;
> @@ -4076,12 +4064,8 @@ bool AsmParser::parseDirectiveSpace(Stri
>
> Lex();
>
> - if (NumBytes <= 0)
> - return TokError("invalid number of bytes in '" + Twine(IDVal) +
> - "' directive");
> -
> // FIXME: Sometimes the fill expr is 'nop' if it isn't supplied,
> instead of 0.
> - getStreamer().EmitFill(NumBytes, FillExpr);
> + getStreamer().emitFill(*NumBytes, FillExpr, NumBytesLoc);
>
> return false;
> }
>
> Modified: llvm/trunk/lib/MC/MCStreamer.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCStreamer.cpp?rev=271028&r1=271027&r2=271028&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/MC/MCStreamer.cpp (original)
> +++ llvm/trunk/lib/MC/MCStreamer.cpp Fri May 27 13:49:44 2016
> @@ -135,9 +135,18 @@ void MCStreamer::EmitGPRel32Value(const
> /// EmitFill - Emit NumBytes bytes worth of the value specified by
> /// FillValue. This implements directives such as '.space'.
> void MCStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue) {
> - const MCExpr *E = MCConstantExpr::create(FillValue, getContext());
> for (uint64_t i = 0, e = NumBytes; i != e; ++i)
> - EmitValue(E, 1);
> + EmitIntValue(FillValue, 1);
> +}
> +
> +void MCStreamer::emitFill(uint64_t NumValues, int64_t Size, int64_t Expr)
> {
> + int64_t NonZeroSize = Size > 4 ? 4 : Size;
> + Expr &= ~0ULL >> (64 - NonZeroSize * 8);
> + for (uint64_t i = 0, e = NumValues; i != e; ++i) {
> + EmitIntValue(Expr, NonZeroSize);
> + if (NonZeroSize < Size)
> + EmitIntValue(0, Size - NonZeroSize);
> + }
> }
>
> /// The implementation in this class just redirects to EmitFill.
> @@ -757,6 +766,9 @@ void MCStreamer::EmitValueImpl(const MCE
> }
> void MCStreamer::EmitULEB128Value(const MCExpr *Value) {}
> void MCStreamer::EmitSLEB128Value(const MCExpr *Value) {}
> +void MCStreamer::emitFill(const MCExpr &NumBytes, uint64_t Value, SMLoc
> Loc) {}
> +void MCStreamer::emitFill(const MCExpr &NumValues, int64_t Size, int64_t
> Expr,
> + SMLoc Loc) {}
> void MCStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t
> Value,
> unsigned ValueSize,
> unsigned MaxBytesToEmit) {}
>
> Modified: llvm/trunk/test/MC/AsmParser/directive_fill.s
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/AsmParser/directive_fill.s?rev=271028&r1=271027&r2=271028&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/MC/AsmParser/directive_fill.s (original)
> +++ llvm/trunk/test/MC/AsmParser/directive_fill.s Fri May 27 13:49:44 2016
> @@ -1,66 +1,53 @@
> # RUN: llvm-mc -triple i386-unknown-unknown %s 2> %t.err | FileCheck %s
> # RUN: FileCheck --check-prefix=CHECK-WARNINGS %s < %t.err
> +# RUN: llvm-mc -triple i386-unknown-unknown -filetype=obj -o %t.o %s 2>
> %t.err
> +# RUN: FileCheck --check-prefix=OBJ-WARNINGS %s < %t.err
>
> # CHECK: TEST0:
> -# CHECK: .byte 10
> +# CHECK: .fill 1, 1, 0xa
> TEST0:
> .fill 1, 1, 10
>
> # CHECK: TEST1:
> -# CHECK: .short 3
> -# CHECK: .short 3
> +# CHECK: .fill 2, 2, 0x3
> TEST1:
> .fill 2, 2, 3
>
> # CHECK: TEST2:
> -# CHECK: .long 4
> -# CHECK: .long 0
> +# CHECK: .fill 1, 8, 0x4
> TEST2:
> .fill 1, 8, 4
>
> # CHECK: TEST3
> -# CHECK: .byte 0
> -# CHECK: .byte 0
> -# CHECK: .byte 0
> -# CHECK: .byte 0
> +# CHECK: .fill 4
> TEST3:
> .fill 4
>
> # CHECK: TEST4
> -# CHECK: .short 0
> -# CHECK: .short 0
> -# CHECK: .short 0
> -# CHECK: .short 0
> +# CHECK: .fill 4, 2
> TEST4:
> .fill 4, 2
>
> # CHECK: TEST5
> -# CHECK: .short 2
> -# CHECK: .byte 0
> -# CHECK: .short 2
> -# CHECK: .byte 0
> -# CHECK: .short 2
> -# CHECK: .byte 0
> -# CHECK: .short 2
> -# CHECK: .byte 0
> +# CHECK: .fill 4, 3, 0x2
> TEST5:
> .fill 4, 3, 2
>
> # CHECK: TEST6
> -# CHECK: .long 2
> -# CHECK: .long 0
> +# CHECK: .fill 1, 8, 0x2
> # CHECK-WARNINGS: '.fill' directive with size greater than 8 has been
> truncated to 8
> TEST6:
> .fill 1, 9, 2
>
> # CHECK: TEST7
> -# CHECK: .long 0
> -# CHECK: .long 0
> +# CHECK: .fill 1, 8, 0x100000000
> # CHECK-WARNINGS: '.fill' directive pattern has been truncated to 32-bits
> TEST7:
> .fill 1, 8, 1<<32
>
> -# CHECK-WARNINGS: '.fill' directive with negative repeat count has no
> effect
> +# CHECK: TEST8
> +# CHECK: .fill -1, 8, 0x1
> +# OBJ-WARNINGS: '.fill' directive with negative repeat count has no effect
> TEST8:
> .fill -1, 8, 1
>
> @@ -69,7 +56,17 @@ TEST9:
> .fill 1, -1, 1
>
> # CHECK: TEST10
> -# CHECK: .short 22136
> -# CHECK: .byte 52
> +# CHECK: .fill 1, 3, 0x12345678
> TEST10:
> .fill 1, 3, 0x12345678
> +
> +# CHECK: TEST11
> +# CHECK: .fill TEST11-TEST10, 1, 0x0
> +TEST11:
> + .fill TEST11 - TEST10
> +
> +# CHECK: TEST12
> +# CHECK: .fill TEST11-TEST12, 3, 0x12345678
> +# OBJ-WARNINGS: '.fill' directive with negative repeat count has no effect
> +TEST12:
> + .fill TEST11 - TEST12, 3, 0x12345678
>
> Modified: llvm/trunk/test/MC/AsmParser/directive_space.s
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/AsmParser/directive_space.s?rev=271028&r1=271027&r2=271028&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/MC/AsmParser/directive_space.s (original)
> +++ llvm/trunk/test/MC/AsmParser/directive_space.s Fri May 27 13:49:44 2016
> @@ -14,3 +14,8 @@ TEST1:
> # CHECK: .space 1
> TEST2:
> .skip 1
> +
> +# CHECK: TEST3
> +# CHECK: .space TEST0-TEST1
> +TEST3:
> + .space TEST0 - TEST1
>
> Added: llvm/trunk/test/MC/AsmParser/symbolic-expression.s
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/AsmParser/symbolic-expression.s?rev=271028&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/MC/AsmParser/symbolic-expression.s (added)
> +++ llvm/trunk/test/MC/AsmParser/symbolic-expression.s Fri May 27 13:49:44
> 2016
> @@ -0,0 +1,17 @@
> +# RUN: llvm-mc -filetype=obj -triple=i386-unknown-elf %s | llvm-objdump
> -t - | FileCheck %s
> +
> +# CHECK: 00000000 .text 00000000 TEST0
> +TEST0:
> + .fill 0x10
> +# CHECK: 00000010 .text 00000000 TEST1
> +TEST1:
> + .fill TEST1 - TEST0 + 0x5
> +# CHECK: 00000025 .text 00000000 TEST2
> +TEST2:
> + .zero TEST2 - (TEST1 + 0x5)
> +# CHECK: 00000035 .text 00000000 TEST3
> +TEST3:
> + .skip (TEST1 - TEST0) * 2
> +# CHECK: 00000055 .text 00000000 TEST4
> +TEST4:
> + .space TEST2 - TEST1, 1
>
>
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