From baa7ce46f19e3584d70e47c8df28c084e76446da Mon Sep 17 00:00:00 2001
From: Samuel Holland <samuel@sholland.org>
Date: Sun, 3 May 2020 17:48:47 +0200
Subject: [PATCH 03/15] Require static native libraries when linking static
 executables

On ELF targets like Linux, gcc/ld will create a dynamically-linked
executable without warning, even when passed `-static`, when asked to
link to a `.so`. Avoid this confusing and unintended behavior by always
using the static version of libraries when trying to link static
executables.

Fixes #54243
---
 src/librustc_codegen_ssa/back/link.rs | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 8bc4e6442..52ff7a52e 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -2081,8 +2081,7 @@ fn add_upstream_rust_crates<'a, B: ArchiveBuilder<'a>>(
     }
 }
 
-/// Link in all of our upstream crates' native dependencies. Remember that all of these upstream
-/// native dependencies are all non-static dependencies. We've got two cases then:
+/// Link in all of our upstream crates' native dependencies. We have two cases:
 ///
 /// 1. The upstream crate is an rlib. In this case we *must* link in the native dependency because
 /// the rlib is just an archive.
@@ -2015,7 +2013,19 @@
                 continue;
             }
             match lib.kind {
-                NativeLibKind::Dylib | NativeLibKind::Unspecified => cmd.link_dylib(name),
+                NativeLibKind::Dylib | NativeLibKind::Unspecified => {
+                    // On some targets, like Linux, linking a static executable inhibits using
+                    // dylibs at all. Force native libraries to be static, even if for example
+                    // an upstream rlib was originally linked against a native shared library.
+                    if crate_type == config::CrateType::Executable
+                        && sess.crt_static(Some(crate_type))
+                        && !sess.target.options.crt_static_allows_dylibs
+                    {
+                        cmd.link_staticlib(name)
+                    } else {
+                        cmd.link_dylib(name)
+                    }
+                },
                 NativeLibKind::Framework => cmd.link_framework(name),
                 NativeLibKind::StaticNoBundle => {
                     // Link "static-nobundle" native libs only if the crate they originate from
