[PATCH] D16349: [AArch64] Fix two bugs in the .inst directive

[Oliver Stannard via llvm-commits]

olista01 created this revision.
olista01 added a reviewer: t.p.northover.
olista01 added a subscriber: llvm-commits.
olista01 set the repository for this revision to rL LLVM.
Herald added subscribers: rengolin, aemerson.

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.

Repository:
  rL LLVM

http://reviews.llvm.org/D16349

Files:
  lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
  test/MC/AArch64/inst-directive.s

Index: test/MC/AArch64/inst-directive.s
===================================================================
--- test/MC/AArch64/inst-directive.s
+++ test/MC/AArch64/inst-directive.s
@@ -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 @@
 // 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
Index: lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
===================================================================
--- lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
+++ lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
@@ -113,8 +113,18 @@
   }
 
   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


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