[lld] r326686 - [ELF] - Report location for div/mod by zero.

[George Rimar via llvm-commits]

Author: grimar
Date: Mon Mar  5 02:02:44 2018
New Revision: 326686

URL: http://llvm.org/viewvc/llvm-project?rev=326686&view=rev
Log:
[ELF] - Report location for div/mod by zero.

"division by zero" or "modulo by zero" are not
very informative errors and even probably confusing
as does not let to know that error is coming from linker script.
Patch adds location reporting.

Differential revision: https://reviews.llvm.org/D43934

Modified:
    lld/trunk/ELF/ScriptParser.cpp
    lld/trunk/test/ELF/linkerscript/operators.test

Modified: lld/trunk/ELF/ScriptParser.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/ScriptParser.cpp?rev=326686&r1=326685&r2=326686&view=diff
==============================================================================
--- lld/trunk/ELF/ScriptParser.cpp (original)
+++ lld/trunk/ELF/ScriptParser.cpp Mon Mar  5 02:02:44 2018
@@ -98,6 +98,7 @@ private:
   uint64_t readMemoryAssignment(StringRef, StringRef, StringRef);
   std::pair<uint32_t, uint32_t> readMemoryAttributes();
 
+  Expr combine(StringRef Op, Expr L, Expr R);
   Expr readExpr();
   Expr readExpr1(Expr Lhs, int MinPrec);
   StringRef readParenLiteral();
@@ -157,20 +158,6 @@ static ExprValue sub(ExprValue A, ExprVa
   return {A.Sec, false, A.getSectionOffset() - B.getValue(), A.Loc};
 }
 
-static ExprValue div(ExprValue A, ExprValue B) {
-  if (uint64_t BV = B.getValue())
-    return A.getValue() / BV;
-  error("division by zero");
-  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,
@@ -809,17 +796,31 @@ Expr ScriptParser::readExpr() {
   return E;
 }
 
-static Expr combine(StringRef Op, Expr L, Expr R) {
+Expr ScriptParser::combine(StringRef Op, Expr L, Expr R) {
   if (Op == "+")
     return [=] { return add(L(), R()); };
   if (Op == "-")
     return [=] { return sub(L(), R()); };
   if (Op == "*")
     return [=] { return L().getValue() * R().getValue(); };
-  if (Op == "/")
-    return [=] { return div(L(), R()); };
-  if (Op == "%")
-    return [=] { return mod(L(), R()); };
+  if (Op == "/") {
+    std::string Loc = getCurrentLocation();
+    return [=]() -> uint64_t {
+      if (uint64_t RV = R().getValue())
+        return L().getValue() / RV;
+      error(Loc + ": division by zero");
+      return (uint64_t)0;
+    };
+  }
+  if (Op == "%") {
+    std::string Loc = getCurrentLocation();
+    return [=]() -> uint64_t {
+      if (uint64_t RV = R().getValue())
+        return L().getValue() % RV;
+      error(Loc + ": modulo by zero");
+      return (uint64_t)0;
+    };
+  }
   if (Op == "<<")
     return [=] { return L().getValue() << R().getValue(); };
   if (Op == ">>")

Modified: lld/trunk/test/ELF/linkerscript/operators.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/linkerscript/operators.test?rev=326686&r1=326685&r2=326686&view=diff
==============================================================================
--- lld/trunk/test/ELF/linkerscript/operators.test (original)
+++ lld/trunk/test/ELF/linkerscript/operators.test Mon Mar  5 02:02:44 2018
@@ -91,7 +91,13 @@ SECTIONS {
 # RUN: echo "SECTIONS { . = 1 / 0; }" > %t.script
 # RUN: not ld.lld %t --script %t.script -o %t2 2>&1 | \
 # RUN:  FileCheck --check-prefix=DIVZERO %s
-# DIVZERO: division by zero
+# DIVZERO: {{.*}}.script:1: division by zero
+
+## Mod by zero error.
+# RUN: echo "SECTIONS { . = 1 % 0; }" > %t.script
+# RUN: not ld.lld %t --script %t.script -o %t2 2>&1 | \
+# RUN:  FileCheck --check-prefix=MODZERO %s
+# MODZERO: {{.*}}.script:1: modulo by zero
 
 ## Broken ternary operator expression.
 # RUN: echo "SECTIONS { . = 1 ? 2; }" > %t.script