[llvm-commits] [llvm] r153153 - in /llvm/trunk: lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp test/MC/Mips/elf-bigendian.ll

[Akira Hatanaka]

Author: ahatanak
Date: Tue Mar 20 19:52:01 2012
New Revision: 153153

URL: http://llvm.org/viewvc/llvm-project?rev=153153&view=rev
Log:
Incremental big endian patch by Jack Carter.

These changes allow us to compile big endian from the command line for 32 bit
Mips targets. This patch will result in code and data actually being produced
in the correct endianess.


Added:
    llvm/trunk/test/MC/Mips/elf-bigendian.ll
Modified:
    llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
    llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp

Modified: llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp?rev=153153&r1=153152&r2=153153&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp (original)
+++ llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp Tue Mar 20 19:52:01 2012
@@ -92,25 +92,42 @@
     if (!Value)
       return; // Doesn't change encoding.
 
+    // Where do we start in the object
     unsigned Offset = Fixup.getOffset();
-    // FIXME: The below code will not work across endian models
-    // How many bytes/bits are we fixing up?
-    unsigned NumBytes = ((getFixupKindInfo(Kind).TargetSize-1)/8)+1;
-    uint64_t Mask = ((uint64_t)1 << getFixupKindInfo(Kind).TargetSize) - 1;
+    // Number of bytes we need to fixup
+    unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
+    // Used to point to big endian bytes
+    unsigned FullSize;
+
+    switch (Kind) {
+    case Mips::fixup_Mips_16:
+      FullSize = 2;
+      break;
+    case Mips::fixup_Mips_64:
+      FullSize = 8;
+      break;
+    default:
+      FullSize = 4;
+      break;
+    }
 
     // Grab current value, if any, from bits.
     uint64_t CurVal = 0;
-    for (unsigned i = 0; i != NumBytes; ++i)
-      CurVal |= ((uint8_t)Data[Offset + i]) << (i * 8);
 
+    for (unsigned i = 0; i != NumBytes; ++i) {
+      unsigned Idx = IsLittle ? i : (FullSize - 1 - i);
+      CurVal |= (uint64_t)((uint8_t)Data[Offset + Idx]) << (i*8);
+    }
+
+    uint64_t Mask = ((uint64_t)(-1) >> (64 - getFixupKindInfo(Kind).TargetSize));
     CurVal = (CurVal & ~Mask) | ((CurVal + Value) & Mask);
 
-    // Write out the bytes back to the code/data bits.
-    // First the unaffected bits and then the fixup.
+    // Write out the fixed up bytes back to the code/data bits.
     for (unsigned i = 0; i != NumBytes; ++i) {
-      Data[Offset + i] = uint8_t((CurVal >> (i * 8)) & 0xff);
+      unsigned Idx = IsLittle ? i : (FullSize - 1 - i);
+      Data[Offset + Idx] = (uint8_t)((CurVal >> (i*8)) & 0xff);
     }
-}
+  }
 
   unsigned getNumFixupKinds() const { return Mips::NumTargetFixupKinds; }
 

Modified: llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp?rev=153153&r1=153152&r2=153153&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp (original)
+++ llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsMCCodeEmitter.cpp Tue Mar 20 19:52:01 2012
@@ -49,9 +49,9 @@
 
   void EmitInstruction(uint64_t Val, unsigned Size, raw_ostream &OS) const {
     // Output the instruction encoding in little endian byte order.
-    for (unsigned i = 0; i != Size; ++i) {
-      EmitByte(Val & 255, OS);
-      Val >>= 8;
+    for (unsigned i = 0; i < Size; ++i) {
+      unsigned Shift = IsLittleEndian ? i * 8 : (Size - 1 - i) * 8;
+      EmitByte((Val >> Shift) & 0xff, OS);
     }
   }
 

Added: llvm/trunk/test/MC/Mips/elf-bigendian.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Mips/elf-bigendian.ll?rev=153153&view=auto
==============================================================================
--- llvm/trunk/test/MC/Mips/elf-bigendian.ll (added)
+++ llvm/trunk/test/MC/Mips/elf-bigendian.ll Tue Mar 20 19:52:01 2012
@@ -0,0 +1,45 @@
+; RUN: llc -filetype=obj -mtriple mips-unknown-linux %s -o - | elf-dump --dump-section-data  | FileCheck %s
+
+; Check that this is big endian.
+; CHECK: ('e_indent[EI_DATA]', 0x02)
+
+; Make sure that a section table (text) entry is correct.
+; CHECK:   (('sh_name', 0x{{[0]*}}5) # '.text'
+; CHECKNEXT:   ('sh_type', 0x{{[0]*}}1)
+; CHECKNEXT:   ('sh_flags', 0x{{[0]*}}6)
+; CHECKNEXT:   ('sh_addr', 0x{{{[0-9,a-f]+}})
+; CHECKNEXT:   ('sh_offset', 0x{{{[0-9,a-f]+}})
+; CHECKNEXT:   ('sh_size', 0x{{{[0-9,a-f]+}})
+; CHECKNEXT:   ('sh_link', 0x{{[0]+}})
+; CHECKNEXT:   ('sh_info', 0x{{[0]+}})
+; CHECKNEXT:   ('sh_addralign', 0x{{[0]*}}4)
+; CHECKNEXT:   ('sh_entsize', 0x{{[0]+}})
+
+; See that at least first 3 instructions are correct: GP prologue
+; CHECKNEXT:   ('_section_data', '3c1c0000 279c0000 0399e021 {{[0-9,a-f]*}}')
+
+; ModuleID = '../br1.c'
+target datalayout = "E-p:32:32:32-i1:8:8-i8:8:32-i16:16:32-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-n32"
+target triple = "mips-unknown-linux"
+
+ at x = global i32 1, align 4
+ at str = private unnamed_addr constant [4 x i8] c"goo\00"
+ at str2 = private unnamed_addr constant [4 x i8] c"foo\00"
+
+define i32 @main() nounwind {
+entry:
+  %0 = load i32* @x, align 4
+  %tobool = icmp eq i32 %0, 0
+  br i1 %tobool, label %if.end, label %foo
+
+if.end:                                           ; preds = %entry
+  %puts = tail call i32 @puts(i8* getelementptr inbounds ([4 x i8]* @str, i32 0, i32 0))
+  br label %foo
+
+foo:                                              ; preds = %entry, %if.end
+  %puts2 = tail call i32 @puts(i8* getelementptr inbounds ([4 x i8]* @str2, i32 0, i32 0))
+  ret i32 0
+}
+
+declare i32 @puts(i8* nocapture) nounwind
+