remove zigrt

adds test case for #394

partially reverts a32b5929ccf8cbf79396d8924097a1a911985dac

4 files changed, 40 insertions, 21 deletions

diff --git a/std/special/builtin.zig b/std/special/builtin.zig
index 17839a51d5..51e6646574 100644
--- a/std/special/builtin.zig
+++ b/std/special/builtin.zig
@@ -1,11 +1,21 @@
 // These functions are provided when not linking against libc because LLVM
 // sometimes generates code that calls them.
 
-// Note that these functions do not return `dest`, like the libc API.
-// The semantics of these functions is dictated by the corresponding
-// LLVM intrinsics, not by the libc API.
 const builtin = @import("builtin");
 
+// Avoid dragging in the debug safety mechanisms into this .o file,
+// unless we're trying to test this file.
+pub coldcc fn panic(msg: []const u8) -> noreturn {
+    if (builtin.is_test) {
+        @import("std").debug.panic("{}", msg);
+    } else {
+        unreachable;
+    }
+}
+
+// Note that memset does not return `dest`, like the libc API.
+// The semantics of memset is dictated by the corresponding
+// LLVM intrinsics, not by the libc API.
 export fn memset(dest: ?&u8, c: u8, n: usize) {
     @setDebugSafety(this, false);
 
@@ -14,6 +24,9 @@ export fn memset(dest: ?&u8, c: u8, n: usize) {
         (??dest)[index] = c;
 }
 
+// Note that memcpy does not return `dest`, like the libc API.
+// The semantics of memcpy is dictated by the corresponding
+// LLVM intrinsics, not by the libc API.
 export fn memcpy(noalias dest: ?&u8, noalias src: ?&const u8, n: usize) {
     @setDebugSafety(this, false);
 
diff --git a/std/special/compiler_rt/index.zig b/std/special/compiler_rt/index.zig
index a19eac4c2c..d005c92ba1 100644
--- a/std/special/compiler_rt/index.zig
+++ b/std/special/compiler_rt/index.zig
@@ -23,6 +23,16 @@ const assert = @import("../../debug.zig").assert;
 
 const __udivmoddi4 = @import("udivmoddi4.zig").__udivmoddi4;
 
+// Avoid dragging in the debug safety mechanisms into this .o file,
+// unless we're trying to test this file.
+pub coldcc fn panic(msg: []const u8) -> noreturn {
+    if (is_test) {
+        @import("std").debug.panic("{}", msg);
+    } else {
+        unreachable;
+    }
+}
+
 export fn __udivdi3(a: u64, b: u64) -> u64 {
     @setDebugSafety(this, is_test);
     @setGlobalLinkage(__udivdi3, builtin.GlobalLinkage.LinkOnce);
diff --git a/std/special/panic.zig b/std/special/panic.zig
new file mode 100644
index 0000000000..78117a5366
--- /dev/null
+++ b/std/special/panic.zig
@@ -0,0 +1,14 @@
+// This file is the default panic handler if the root source file does not
+// have a `pub fn panic`.
+// If this file wants to import other files *by name*, support for that would
+// have to be added in the compiler.
+
+const builtin = @import("builtin");
+
+pub coldcc fn panic(msg: []const u8) -> noreturn {
+    if (builtin.os == builtin.Os.freestanding) {
+        while (true) {}
+    } else {
+        @import("std").debug.panic("{}", msg);
+    }
+}
diff --git a/std/special/zigrt.zig b/std/special/zigrt.zig
deleted file mode 100644
index 26d5a161c7..0000000000
--- a/std/special/zigrt.zig
+++ /dev/null
@@ -1,18 +0,0 @@
-// This file contains functions that zig depends on to coordinate between
-// multiple .o files. The symbols are defined LinkOnce so that multiple
-// instances of zig_rt.zig do not conflict with each other.
-
-const builtin = @import("builtin");
-
-export coldcc fn __zig_panic(message_ptr: &const u8, message_len: usize) -> noreturn {
-    @setGlobalLinkage(__zig_panic, builtin.GlobalLinkage.LinkOnce);
-    @setDebugSafety(this, false);
-
-    if (builtin.__zig_panic_implementation_provided) {
-        @import("@root").panic(message_ptr[0..message_len]);
-    } else if (builtin.os == builtin.Os.freestanding) {
-        while (true) {}
-    } else {
-        @import("std").debug.panic("{}", message_ptr[0..message_len]);
-    }
-}