[llvm] r258308 - [AArch64] Fix two bugs in the .inst directive

[Chad Rosier via llvm-commits]

Am I correct in assuming this is something that should be included in the
3.8 release, Tim?

 Chad

> Author: olista01
> Date: Wed Jan 20 06:54:31 2016
> New Revision: 258308
>
> URL: http://llvm.org/viewvc/llvm-project?rev=258308&view=rev
> Log:
> [AArch64] Fix two bugs in the .inst directive
>
> The AArch64 .inst directive was implemented using EmitIntValue, which
> resulted
> in both $x and $d (code and data) mapping symbols being emitted at the
> same
> address. This fixes it to only emit the $x mapping symbol.
>
> EmitIntValue also emits the value in big-endian order when targeting
> big-endian
> systems, but instructions are always emitted in little-endian order for
> AArch64.
>
> Differential Revision: http://reviews.llvm.org/D16349
>
>
> Modified:
>     llvm/trunk/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
>     llvm/trunk/test/MC/AArch64/inst-directive.s
>
> Modified:
> llvm/trunk/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp?rev=258308&r1=258307&r2=258308&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
> (original)
> +++ llvm/trunk/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp Wed
> Jan 20 06:54:31 2016
> @@ -112,9 +112,21 @@ public:
>      MCELFStreamer::EmitInstruction(Inst, STI);
>    }
>
> +  /// Emit a 32-bit value as an instruction. This is only used for the
> .inst
> +  /// directive, EmitInstruction should be used in other cases.
>    void emitInst(uint32_t Inst) {
> +    char Buffer[4];
> +
> +    // We can't just use EmitIntValue here, as that will emit a data
> mapping
> +    // symbol, and swap the endianness on big-endian systems
> (instructions are
> +    // always little-endian).
> +    for (unsigned I = 0; I < 4; ++I) {
> +      Buffer[I] = uint8_t(Inst);
> +      Inst >>= 8;
> +    }
> +
>      EmitA64MappingSymbol();
> -    MCELFStreamer::EmitIntValue(Inst, 4);
> +    MCELFStreamer::EmitBytes(StringRef(Buffer, 4));
>    }
>
>    /// This is one of the functions used to emit data into an ELF section,
> so the
>
> Modified: llvm/trunk/test/MC/AArch64/inst-directive.s
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/AArch64/inst-directive.s?rev=258308&r1=258307&r2=258308&view=diff
> ==============================================================================
> --- llvm/trunk/test/MC/AArch64/inst-directive.s (original)
> +++ llvm/trunk/test/MC/AArch64/inst-directive.s Wed Jan 20 06:54:31 2016
> @@ -1,7 +1,14 @@
>  // RUN: llvm-mc %s -triple=aarch64-none-linux-gnu -filetype=asm -o - \
>  // RUN:   | FileCheck %s --check-prefix=CHECK-ASM
> -// RUN: llvm-mc %s -triple=aarch64-none-linux-gnu -filetype=obj -o - \
> -// RUN:   | llvm-readobj -s -sd | FileCheck %s  --check-prefix=CHECK-OBJ
> +// RUN: llvm-mc %s -triple=aarch64-none-linux-gnu -filetype=obj -o %t
> +// RUN: llvm-readobj -s -sd %t | FileCheck %s  --check-prefix=CHECK-OBJ
> +// RUN: llvm-objdump -t %t | FileCheck %s  --check-prefix=CHECK-SYMS
> +
> +// RUN: llvm-mc %s -triple=aarch64_be-none-linux-gnu -filetype=asm -o - \
> +// RUN:   | FileCheck %s --check-prefix=CHECK-ASM
> +// RUN: llvm-mc %s -triple=aarch64_be-none-linux-gnu -filetype=obj -o %t
> +// RUN: llvm-readobj -s -sd %t | FileCheck %s  --check-prefix=CHECK-OBJ
> +// RUN: llvm-objdump -t %t | FileCheck %s  --check-prefix=CHECK-SYMS
>
>      .section    .inst.aarch64_inst
>
> @@ -22,3 +29,7 @@ aarch64_inst:
>  // CHECK-OBJ:   SectionData (
>  // CHECK-OBJ-NEXT: 0000: 2040105E
>  // CHECK-OBJ-NEXT: )
> +
> +// CHECK-SYMS-NOT: 0000000000000000         .inst.aarch64_inst
>   00000000 $d
> +// CHECK-SYMS:     0000000000000000         .inst.aarch64_inst
>   00000000 $x
> +// CHECK-SYMS-NOT: 0000000000000000         .inst.aarch64_inst
>   00000000 $d
>
>
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