Fix hex strings being printed as regular strings

compiler/src/dmd/common/outbuffer.d

@@ -755,6 +755,25 @@ struct OutBuffer
         } while (value);
     }
 
+    /**
+     * Write an array as a string of hexadecimal digits
+     * Params:
+     *     data = bytes to write
+     *     upperCase = whether to upper case hex digits A-F
+     */
+    void writeHexString(scope const(ubyte)[] data, bool upperCase) pure nothrow @safe
+    {
+        auto slice = this.allocate(2 * data.length);
+        const a = upperCase ? 'A' : 'a';
+        foreach (i, c; data)
+        {
+            char hi = (c >> 4) & 0xF;
+            slice[i * 2] = cast(char)(hi < 10 ? hi + '0' : hi - 10 + a);
+            char lo = c & 0xF;
+            slice[i * 2 + 1] = cast(char)(lo < 10 ? lo + '0' : lo - 10 + a);
+        }
+    }
+
     /**
     Destructively saves the contents of `this` to `filename`. As an
     optimization, if the file already has identical contents with the buffer,
@@ -943,3 +962,11 @@ unittest
     else
         assert(buf[] == "\nabc\n\n");
 }
+
+unittest
+{
+    OutBuffer buf;
+    buf.writeHexString([0xAA, 0xBB], false);
+    buf.writeHexString([0xCC], true);
+    assert(buf[] == "aabbCC");
+}

compiler/src/dmd/dmangle.d

@@ -1004,14 +1004,7 @@ public:
         buf.writeByte(m);
         buf.print(q.length);
         buf.writeByte('_');    // nbytes <= 11
-        auto slice = buf.allocate(2 * q.length);
-        foreach (i, c; q)
-        {
-            char hi = (c >> 4) & 0xF;
-            slice[i * 2] = cast(char)(hi < 10 ? hi + '0' : hi - 10 + 'a');
-            char lo = c & 0xF;
-            slice[i * 2 + 1] = cast(char)(lo < 10 ? lo + '0' : lo - 10 + 'a');
-        }
+        buf.writeHexString(cast(const(ubyte)[]) q, false);
     }
 
     override void visit(ArrayLiteralExp e)

compiler/src/dmd/hdrgen.d

@@ -2276,6 +2276,16 @@ private void expressionPrettyPrint(Expression e, ref OutBuffer buf, ref HdrGenSt
 
     void visitString(StringExp e)
     {
+        if (e.hexString || e.sz == 8)
+        {
+            buf.writeByte('x');
+            buf.writeByte('"');
+            buf.writeHexString(e.peekData, true);
+            buf.writeByte('"');
+            if (e.postfix)
+                buf.writeByte(e.postfix);
+            return;
+        }
         buf.writeByte('"');
         const o = buf.length;
         foreach (i; 0 .. e.len)

compiler/test/fail_compilation/fail136.d

@@ -1,7 +1,7 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation\fail136.d(10): Error: `"\xef\xbb\xbf"` has no effect
+fail_compilation/fail136.d(10): Error: `x"EFBBBF"` has no effect
 ---
 */
 

compiler/test/fail_compilation/hexstring.d

@@ -2,8 +2,8 @@
 TEST_OUTPUT:
 ---
 fail_compilation/hexstring.d(29): Error: cannot implicitly convert expression `"123F"` of type `string` to `immutable(ubyte[])`
-fail_compilation/hexstring.d(30): Error: cannot implicitly convert expression `"\x12?"c` of type `string` to `immutable(ubyte[])`
-fail_compilation/hexstring.d(31): Error: cannot implicitly convert expression `"\x12?"` of type `string` to `immutable(ubyte[])`
+fail_compilation/hexstring.d(30): Error: cannot implicitly convert expression `x"123F"c` of type `string` to `immutable(ubyte[])`
+fail_compilation/hexstring.d(31): Error: cannot implicitly convert expression `x"123F"` of type `string` to `immutable(ubyte[])`
 fail_compilation/hexstring.d(33): Error: hex string length 1 must be a multiple of 2 to cast to `immutable(ushort[])`
 fail_compilation/hexstring.d(34): Error: hex string length 3 must be a multiple of 4 to cast to `immutable(uint[])`
 fail_compilation/hexstring.d(35): Error: hex string length 5 must be a multiple of 8 to cast to `immutable(ulong[])`
@@ -13,7 +13,7 @@ fail_compilation/hexstring.d(37): Error: array cast from `string` to `immutable(
 fail_compilation/hexstring.d(38): Error: array cast from `string` to `immutable(ushort[])` is not supported at compile time
 fail_compilation/hexstring.d(39): Error: array cast from `string` to `immutable(uint[])` is not supported at compile time
 fail_compilation/hexstring.d(39):        perhaps remove postfix `c` from hex string
-fail_compilation/hexstring.d(28): Error: cannot implicitly convert expression `"\x12?"` of type `string` to `ubyte[]`
+fail_compilation/hexstring.d(28): Error: cannot implicitly convert expression `x"123F"` of type `string` to `ubyte[]`
 ---
 */
 

compiler/test/runnable/literal.d

@@ -256,6 +256,10 @@ void testHexstring()
     // Test that mangling of StringExp with size 8 is the same as array literal mangling:
     void f(immutable ulong[] a)() {}
     static assert(f!y.mangleof == f!([0x1122334455667788, 0xAABBCCDDEEFF0099]).mangleof);
+
+    // Test printing StringExp with size 8
+    enum toStr(immutable ulong[] v) = v.stringof;
+    static assert(toStr!y == `x"88776655443322119900FFEEDDCCBBAA"`);
 }
 
 /***************************************************/