[PATCH] D43883: Add "%" operator to the linker script.

[Rafael Avila de Espindola via llvm-commits]

LGTM

out of curiosity, what uses it?

Cheers,
Rafael

Rui Ueyama via Phabricator <reviews at reviews.llvm.org> writes:

> ruiu created this revision.
> ruiu added a reviewer: rafael.
> Herald added subscribers: arichardson, emaste.
>
> This patch improves compatibility with GNU linkers.
>
>
> https://reviews.llvm.org/D43883
>
> Files:
>   lld/ELF/ScriptParser.cpp
>   lld/test/ELF/linkerscript/operators.s
>
>
> Index: lld/test/ELF/linkerscript/operators.s
> ===================================================================
> --- lld/test/ELF/linkerscript/operators.s
> +++ lld/test/ELF/linkerscript/operators.s
> @@ -5,6 +5,7 @@
>  # RUN:  plus = 1 + 2 + 3; \
>  # RUN:  minus = 5 - 1; \
>  # RUN:  div = 6 / 2; \
> +# RUN:  mod = 20 % 7; \
>  # RUN:  mul = 1 + 2 * 3; \
>  # RUN:  nospace = 1+2*6/3; \
>  # RUN:  braces = 1 + (2 + 3) * 4; \
> @@ -37,6 +38,7 @@
>  # CHECK: 00000000000006 *ABS* 00000000 plus
>  # CHECK: 00000000000004 *ABS* 00000000 minus
>  # CHECK: 00000000000003 *ABS* 00000000 div
> +# CHECK: 00000000000006 *ABS* 00000000 mod
>  # CHECK: 00000000000007 *ABS* 00000000 mul
>  # CHECK: 00000000000005 *ABS* 00000000 nospace
>  # CHECK: 00000000000015 *ABS* 00000000 braces
> Index: lld/ELF/ScriptParser.cpp
> ===================================================================
> --- lld/ELF/ScriptParser.cpp
> +++ lld/ELF/ScriptParser.cpp
> @@ -168,6 +168,13 @@
>    return 0;
>  }
>  
> +static ExprValue mod(ExprValue A, ExprValue B) {
> +  if (uint64_t BV = B.getValue())
> +    return A.getValue() % BV;
> +  error("modulo by zero");
> +  return 0;
> +}
> +
>  static ExprValue bitAnd(ExprValue A, ExprValue B) {
>    moveAbsRight(A, B);
>    return {A.Sec, A.ForceAbsolute,
> @@ -461,7 +468,7 @@
>  
>  static int precedence(StringRef Op) {
>    return StringSwitch<int>(Op)
> -      .Cases("*", "/", 5)
> +      .Cases("*", "/", "%", 5)
>        .Cases("+", "-", 4)
>        .Cases("<<", ">>", 3)
>        .Cases("<", "<=", ">", ">=", "==", "!=", 2)
> @@ -811,6 +818,8 @@
>      return [=] { return mul(L(), R()); };
>    if (Op == "/")
>      return [=] { return div(L(), R()); };
> +  if (Op == "%")
> +    return [=] { return mod(L(), R()); };
>    if (Op == "<<")
>      return [=] { return L().getValue() << R().getValue(); };
>    if (Op == ">>")
>
>
> Index: lld/test/ELF/linkerscript/operators.s
> ===================================================================
> --- lld/test/ELF/linkerscript/operators.s
> +++ lld/test/ELF/linkerscript/operators.s
> @@ -5,6 +5,7 @@
>  # RUN:  plus = 1 + 2 + 3; \
>  # RUN:  minus = 5 - 1; \
>  # RUN:  div = 6 / 2; \
> +# RUN:  mod = 20 % 7; \
>  # RUN:  mul = 1 + 2 * 3; \
>  # RUN:  nospace = 1+2*6/3; \
>  # RUN:  braces = 1 + (2 + 3) * 4; \
> @@ -37,6 +38,7 @@
>  # CHECK: 00000000000006 *ABS* 00000000 plus
>  # CHECK: 00000000000004 *ABS* 00000000 minus
>  # CHECK: 00000000000003 *ABS* 00000000 div
> +# CHECK: 00000000000006 *ABS* 00000000 mod
>  # CHECK: 00000000000007 *ABS* 00000000 mul
>  # CHECK: 00000000000005 *ABS* 00000000 nospace
>  # CHECK: 00000000000015 *ABS* 00000000 braces
> Index: lld/ELF/ScriptParser.cpp
> ===================================================================
> --- lld/ELF/ScriptParser.cpp
> +++ lld/ELF/ScriptParser.cpp
> @@ -168,6 +168,13 @@
>    return 0;
>  }
>  
> +static ExprValue mod(ExprValue A, ExprValue B) {
> +  if (uint64_t BV = B.getValue())
> +    return A.getValue() % BV;
> +  error("modulo by zero");
> +  return 0;
> +}
> +
>  static ExprValue bitAnd(ExprValue A, ExprValue B) {
>    moveAbsRight(A, B);
>    return {A.Sec, A.ForceAbsolute,
> @@ -461,7 +468,7 @@
>  
>  static int precedence(StringRef Op) {
>    return StringSwitch<int>(Op)
> -      .Cases("*", "/", 5)
> +      .Cases("*", "/", "%", 5)
>        .Cases("+", "-", 4)
>        .Cases("<<", ">>", 3)
>        .Cases("<", "<=", ">", ">=", "==", "!=", 2)
> @@ -811,6 +818,8 @@
>      return [=] { return mul(L(), R()); };
>    if (Op == "/")
>      return [=] { return div(L(), R()); };
> +  if (Op == "%")
> +    return [=] { return mod(L(), R()); };
>    if (Op == "<<")
>      return [=] { return L().getValue() << R().getValue(); };
>    if (Op == ">>")