From 7826c40e26929f391c4ae317b248de0832e226a9 Mon Sep 17 00:00:00 2001
From: Mamy Ratsimbazafy <mamy_github@numforge.co>
Date: Sun, 11 Oct 2020 21:36:16 +0200
Subject: [PATCH] Unify GCC and Clang ASM (#103)

* GCC-10 on Mac seems to require this syntax instead of the "+"

* update comment
---
 constantine/primitives/macro_assembler_x86.nim | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/constantine/primitives/macro_assembler_x86.nim b/constantine/primitives/macro_assembler_x86.nim
index 1839b72..70a79cc 100644
--- a/constantine/primitives/macro_assembler_x86.nim
+++ b/constantine/primitives/macro_assembler_x86.nim
@@ -286,6 +286,9 @@ func getStrOffset(a: Assembler_x86, op: Operand): string =
 
   # Beware GCC / Clang differences with array offsets
   # https://lists.llvm.org/pipermail/llvm-dev/2017-August/116202.html
+  # - 8+%rax works with GCC
+  # - 8%rax works with Clang
+  # - 8(%rax) works with both
 
   if op.desc.rm in {Mem, AnyRegOrMem, MemOffsettable, AnyMemOffImm, AnyRegMemImm}:
     # Directly accessing memory
@@ -302,12 +305,11 @@ func getStrOffset(a: Assembler_x86, op: Operand): string =
        (op.desc.rm == ElemsInReg and op.kind == kFromArray):
     if op.offset == 0:
       return "(%" & $op.desc.asmId & ')'
-    if defined(gcc):
-      return $(op.offset * a.wordSize) & "+(%" & $op.desc.asmId & ')'
-    elif defined(clang):
-      return $(op.offset * a.wordSize) & "(%" & $op.desc.asmId & ')'
-    else:
-      error "Unconfigured compiler"
+    # GCC & Clang seemed to disagree on pointer indexing
+    # in the past and required different codegen
+    # if defined(gcc):
+    #   return $(op.offset * a.wordSize) & "+(%" & $op.desc.asmId & ')'
+    return $(op.offset * a.wordSize) & "(%" & $op.desc.asmId & ')'
   else:
     error "Unsupported: " & $op.desc.rm.ord