compiler: optimize code generation for constant string indexing expre…

…ssions
julelang · Aug 11, 2024 · 980a933 · 980a933
1 parent d335edf
commit 980a933
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Showing 3 changed files with 46 additions and 0 deletions.
diff --git a/api/str.hpp b/api/str.hpp
@@ -83,6 +83,31 @@ namespace jule
             return s;
         }
 
+        // Returns element by index.
+        // Includes safety checking.
+        // Designed for constant strings.
+        static jule::U8 at(
+#ifndef __JULE_ENABLE__PRODUCTION
+            const char *file,
+#endif
+            const jule::U8 *s, const jule::Int n, const jule::Int i) noexcept
+        {
+#ifndef __JULE_DISABLE__SAFETY
+            if (n == 0 || i < 0 || n <= i)
+            {
+                std::string error;
+                __JULE_WRITE_ERROR_INDEX_OUT_OF_RANGE(error, i, n);
+                error += "\nruntime: string indexing with out of range index";
+#ifndef __JULE_ENABLE__PRODUCTION
+                error += "\nfile: ";
+                error += file;
+#endif
+                jule::panic(error);
+            }
+#endif
+            return s[i];
+        }
+
         Str(void) : _len(0) {};
         Str(const jule::Str &src) : buffer(src.buffer), _len(src._len), _slice(src._slice) {}
         Str(jule::Str &&src) : buffer(std::move(src.buffer)), _len(src._len), _slice(src._slice) {}

diff --git a/src/julec/obj/cxx/expr.jule b/src/julec/obj/cxx/expr.jule
@@ -840,6 +840,26 @@ impl exprCoder {
     }
 
     fn indexing(mut &self, mut m: &IndexingExprModel) {
+        match type m.Expr.Model {
+        | &Const:
+            // Cosntant string indexed. Use fast way, avoid making literal.
+            self.oc.write(typeCoder.Str + "::at(")
+            if !env::Production {
+                self.oc.write("\"")
+                self.oc.locInfo(m.Token)
+                self.oc.write("\", ")
+            }
+            self.oc.write("reinterpret_cast<const " + typeCoder.U8 + "*>(")
+            s := (&Const)(m.Expr.Model).ReadStr()
+            cstrLit(self.oc.Buf, s)
+            self.oc.write("), ")
+            self.oc.write(conv::Itoa(len(s)))
+            self.oc.write(", ")
+            self.possibleRefExpr(m.Index.Model)
+            self.oc.write(")")
+            ret
+        }
+
         self.possibleRefExpr(m.Expr.Model)
         // Index access with safety measures.
         match {

diff --git a/src/julec/obj/cxx/type.jule b/src/julec/obj/cxx/type.jule
@@ -61,6 +61,7 @@ impl typeCoder {
     const Bool = "jule::Bool"
     const Int = "jule::Int"
     const Uintptr = "jule::Uintptr"
+    const U8 = "jule::U8"
 
     static fn new(mut &oc: &ObjectCoder): &typeCoder {
         mut tc := &typeCoder{oc: oc}