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

[Rui Ueyama via Phabricator via llvm-commits]

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 == ">>")


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