[lld] [LLD][COFF] Emit warnings for missing load config on EC targets (PR #121339)

[Jacek Caban via llvm-commits]

https://github.com/cjacek created https://github.com/llvm/llvm-project/pull/121339

ARM64EC and ARM64X images require a load configuration to be valid.

>From 3cd5e5de96fcff1a5452d0cacbae65f6f61364ee Mon Sep 17 00:00:00 2001
From: Jacek Caban <jacek at codeweavers.com>
Date: Mon, 9 Dec 2024 16:53:58 +0100
Subject: [PATCH] [LLD][COFF] Emit warnings for missing load config on EC
 targets

ARM64EC and ARM64X images require a load configuration to be valid.
---
 lld/COFF/SymbolTable.cpp          |  8 ++++++++
 lld/test/COFF/arm64x-loadconfig.s | 14 +++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lld/COFF/SymbolTable.cpp b/lld/COFF/SymbolTable.cpp
index fc78afb4c9e400..2f21f3cea7e2a3 100644
--- a/lld/COFF/SymbolTable.cpp
+++ b/lld/COFF/SymbolTable.cpp
@@ -601,6 +601,14 @@ void SymbolTable::initializeLoadConfig() {
   auto sym =
       dyn_cast_or_null<DefinedRegular>(findUnderscore("_load_config_used"));
   if (!sym) {
+    if (isEC()) {
+      Warn(ctx) << "EC version of '_load_config_used' is missing";
+      return;
+    }
+    if (ctx.hybridSymtab) {
+      Warn(ctx) << "native version of '_load_config_used' is missing for ARM64X target";
+      return;
+    }
     if (ctx.config.guardCF != GuardCFLevel::Off)
       Warn(ctx)
           << "Control Flow Guard is enabled but '_load_config_used' is missing";
diff --git a/lld/test/COFF/arm64x-loadconfig.s b/lld/test/COFF/arm64x-loadconfig.s
index 8d2ab555546341..d21f4bfe95b843 100644
--- a/lld/test/COFF/arm64x-loadconfig.s
+++ b/lld/test/COFF/arm64x-loadconfig.s
@@ -8,7 +8,19 @@
 // RUN: llvm-mc -filetype=obj -triple=aarch64-windows loadconfig-short.s -o loadconfig-short.obj
 // RUN: llvm-mc -filetype=obj -triple=arm64ec-windows loadconfig-short.s -o loadconfig-short-arm64ec.obj
 
-// RUN: lld-link -machine:arm64x -out:out.dll -dll -noentry loadconfig.obj test.obj
+// RUN: lld-link -machine:arm64x -out:out-warn.dll -dll -noentry test.obj \
+// RUN:           2>&1 | FileCheck --check-prefixes=WARN-LOADCFG,WARN-EC-LOADCFG %s
+// WARN-LOADCFG:    lld-link: warning: native version of '_load_config_used' is missing for ARM64X target
+// WARN-EC-LOADCFG: lld-link: warning: EC version of '_load_config_used' is missing
+
+// RUN: lld-link -machine:arm64x -out:out-nonative.dll -dll -noentry loadconfig-ec.obj chpe.obj \
+// RUN:           2>&1 | FileCheck --check-prefixes=WARN-LOADCFG --implicit-check-not EC %s
+
+// RUN: lld-link -machine:arm64ec -out:out-ec.dll -dll -noentry chpe.obj \
+// RUN:           2>&1 | FileCheck --check-prefixes=WARN-EC-LOADCFG --implicit-check-not native %s
+
+// RUN: lld-link -machine:arm64x -out:out.dll -dll -noentry loadconfig.obj test.obj \
+// RUN:           2>&1 | FileCheck --check-prefixes=WARN-EC-LOADCFG --implicit-check-not native %s
 
 // RUN: llvm-readobj --coff-load-config out.dll | FileCheck --check-prefix=DYNRELOCS %s
 // DYNRELOCS:      DynamicValueRelocTableOffset: 0xC