<div dir="ltr">Sorry I didn't closely at your command lines. I think you need to add -x86-asm-syntax to your assembler command line to force it out of at&t syntax into intel syntax.<div><br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">~Craig</div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, May 12, 2019 at 9:36 PM Craig Topper <<a href="mailto:craig.topper@gmail.com">craig.topper@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">I believe -x86-asm-syntax controls the printer format for clang and llc and may not have any effect on llvm-mc. <div><br></div><div>I'm looking to see if there is a command line option to control the parser syntax or if you have to use ".intel_syntax in the input"<br><div><br clear="all"><div><div dir="ltr" class="gmail-m_-4592280663850775293gmail_signature">~Craig</div></div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, May 12, 2019 at 9:24 PM s nedunuri via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">It looks to me like llvm-mc is doing something strange. Eg:<span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">
<span style="font-size:9pt;font-family:"Lucida Console"">echo "pop
ebp" | llvm-mc -assemble -arch=x86 -filetype=obj -o temp.bin<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">Now disassembling temp.bin:<span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console";color:rgb(191,191,0)"><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">$ llvm-objdump -disassemble -x86-asm-syntax=intel
-section-headers temp.bin<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">temp.bin:
file format COFF-i386<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">Disassembly of section .text:<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">0000000000000000 .text:<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">
0: 8f 05 00 00 00
00 pop dword ptr
[0]<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">Sections:<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">Idx
Name
Size
Address Type<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""> 0
.text 00000006 0000000000000000
TEXT<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""> 1
.data 00000000 0000000000000000
DATA<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""> 2
.bss 00000000
0000000000000000 BSS<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span> </span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">Llvm-mc is generating the opcode 8f, which is why its
getting disassembled as “pop dword ptr [0]”. Looking at the intel
reference for pop you’ll see that the “8f” opcodes are for pops to memory
locations, not to registers. If I create a file "simple.s" containing "pop ebp" using a different assembler (eg nasm) generates
the correct opcode (5D):<span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">$ nasm -f win32 simple.s -l simple.lst<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console"">$ more simple.lst<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""> 1 00000000
5D
POP EBP</span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">Anyone know what's going on? Did I miss a flag somewhere<br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif">thanks</p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><br></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span style="font-size:9pt;font-family:"Lucida Console""><span></span></span></p>
</div>
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