ELF: Redefine parseExpr to parse an expression. NFC.

Previously the function reads an operator and the rest of
the expressions. This patch makes it to actually parse an expression
which starts with a primary pexression followed by other expressions
concatenated with operators.

llvm-svn: 266912

1 files changed, 12 insertions, 9 deletions

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 10008568d9f..0db250c4cca 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -64,8 +64,7 @@ static StringRef next(ArrayRef<StringRef> &Tokens) {
   return Tok;
 }
 
-static uint64_t parseExpr(uint64_t Lhs, int MinPrec,
-                          ArrayRef<StringRef> &Tokens, uint64_t Dot);
+static uint64_t parseExpr(ArrayRef<StringRef> &Tokens, uint64_t Dot);
 
 // This is a part of the operator-precedence parser to evaluate
 // arithmetic expressions in SECTIONS command. This function evaluates an
@@ -75,8 +74,7 @@ static uint64_t parsePrimary(ArrayRef<StringRef> &Tokens, uint64_t Dot) {
   if (Tok == ".")
     return Dot;
   if (Tok == "(") {
-    uint64_t V = parsePrimary(Tokens, Dot);
-    V = parseExpr(V, 0, Tokens, Dot);
+    uint64_t V = parseExpr(Tokens, Dot);
     if (Tokens.empty()) {
       error(") expected");
     } else {
@@ -111,8 +109,9 @@ static uint64_t apply(StringRef Op, uint64_t L, uint64_t R) {
 
 // This is an operator-precedence parser to evaluate
 // arithmetic expressions in SECTIONS command.
-static uint64_t parseExpr(uint64_t Lhs, int MinPrec,
-                          ArrayRef<StringRef> &Tokens, uint64_t Dot) {
+// Tokens should start with an operator.
+static uint64_t parseExpr1(uint64_t Lhs, int MinPrec,
+                           ArrayRef<StringRef> &Tokens, uint64_t Dot) {
   while (!Tokens.empty()) {
     // Read an operator and an expression.
     StringRef Op1 = Tokens.front();
@@ -129,7 +128,7 @@ static uint64_t parseExpr(uint64_t Lhs, int MinPrec,
       StringRef Op2 = Tokens.front();
       if (precedence(Op2) <= precedence(Op1))
         break;
-      Rhs = parseExpr(Rhs, precedence(Op2), Tokens, Dot);
+      Rhs = parseExpr1(Rhs, precedence(Op2), Tokens, Dot);
     }
 
     Lhs = apply(Op1, Lhs, Rhs);
@@ -137,10 +136,14 @@ static uint64_t parseExpr(uint64_t Lhs, int MinPrec,
   return Lhs;
 }
 
+static uint64_t parseExpr(ArrayRef<StringRef> &Tokens, uint64_t Dot) {
+  uint64_t V = parsePrimary(Tokens, Dot);
+  return parseExpr1(V, 0, Tokens, Dot);
+}
+
 // Evaluates the expression given by list of tokens.
 static uint64_t evaluate(ArrayRef<StringRef> Tokens, uint64_t Dot) {
-  uint64_t V = parsePrimary(Tokens, Dot);
-  V = parseExpr(V, 0, Tokens, Dot);
+  uint64_t V = parseExpr(Tokens, Dot);
   if (!Tokens.empty())
     error("stray token: " + Tokens[0]);
   return V;