Merge pull request #5286 from Feoramund/no-san-mem

Add `@(no_sanitize_memory)` with additions to `base:sanitizer`

base/sanitizer/memory.odin

@@ -0,0 +1,74 @@
+#+no-instrumentation
+package sanitizer
+
+@(private="file")
+MSAN_ENABLED :: .Memory in ODIN_SANITIZER_FLAGS
+
+@(private="file")
+@(default_calling_convention="system")
+foreign {
+	__msan_unpoison :: proc(addr: rawptr, size: uint) ---
+}
+
+/*
+Marks a slice as fully initialized.
+
+Code instrumented with `-sanitize:memory` will be permitted to access any
+address within the slice as if it had already been initialized.
+
+When msan is not enabled this procedure does nothing.
+*/
+memory_unpoison_slice :: proc "contextless" (region: $T/[]$E) {
+	when MSAN_ENABLED {
+		__msan_unpoison(raw_data(region),  size_of(E) * len(region))
+	}
+}
+
+/*
+Marks a pointer as fully initialized.
+
+Code instrumented with `-sanitize:memory` will be permitted to access memory
+within the region the pointer points to as if it had already been initialized.
+
+When msan is not enabled this procedure does nothing.
+*/
+memory_unpoison_ptr :: proc "contextless" (ptr: ^$T) {
+	when MSAN_ENABLED {
+		__msan_unpoison(ptr, size_of(T))
+	}
+}
+
+/*
+Marks the region covering `[ptr, ptr+len)` as fully initialized.
+
+Code instrumented with `-sanitize:memory` will be permitted to access memory
+within this range as if it had already been initialized.
+
+When msan is not enabled this procedure does nothing.
+*/
+memory_unpoison_rawptr :: proc "contextless" (ptr: rawptr, len: int) {
+	when MSAN_ENABLED {
+		__msan_unpoison(ptr, uint(len))
+	}
+}
+
+/*
+Marks the region covering `[ptr, ptr+len)` as fully initialized.
+
+Code instrumented with `-sanitize:memory` will be permitted to access memory
+within this range as if it had already been initialized.
+
+When msan is not enabled this procedure does nothing.
+*/
+memory_unpoison_rawptr_uint :: proc "contextless" (ptr: rawptr, len: uint) {
+	when MSAN_ENABLED {
+		__msan_unpoison(ptr, len)
+	}
+}
+
+memory_unpoison :: proc {
+	memory_unpoison_slice,
+	memory_unpoison_ptr,
+	memory_unpoison_rawptr,
+	memory_unpoison_rawptr_uint,
+}