From 625152440c8a409beaf8c758c4d0f966e8bc935e Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Thu, 26 Dec 2024 21:02:10 +0100
Subject: [PATCH] Use `weak_odr` rather than `weak` on Windows which seems to
 prevent issues such as #1704. Fix regression.

---
 .github/workflows/main.yml                     |  5 +++++
 releasenotes.md                                |  3 ++-
 src/compiler/compiler.c                        |  4 ++++
 src/compiler/llvm_codegen.c                    |  2 +-
 .../functions/test_regression_mingw.c3t        | 18 +++++++++---------
 5 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 403034ba8..5638dceeb 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -647,6 +647,11 @@ jobs:
           cd test
           ../build/c3c compile-test unit
 
+      - name: Test WASM
+        run: |
+          cd resources/testfragments
+          ../../build/c3c compile --target wasm32 -g0 --no-entry -Os wasm4.c3
+
       - name: Build testproject
         run: |
           cd resources/testproject
diff --git a/releasenotes.md b/releasenotes.md
index 6c210f72d..49b4a0fd9 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -24,7 +24,8 @@
 - Fix bug in temp allocator when temp memory is exhausted and allocation needs overaligned mem. #1715
 - Incorrectly handles distinct enums and pointers with '+=' and '-=' #1717.
 - Prevent DString from being initialized with "".
-- Fix bug in OnStackAllocator when freeing overallocated data. # #1720
+- Fix bug in OnStackAllocator when freeing overallocated data. #1720
+- Use `weak_odr` rather than `weak` on Windows which seems to prevent issues such as #1704.
 
 ### Stdlib changes
 - Increase BitWriter.write_bits limit up to 32 bits.
diff --git a/src/compiler/compiler.c b/src/compiler/compiler.c
index cc6791efe..6b26e18ae 100644
--- a/src/compiler/compiler.c
+++ b/src/compiler/compiler.c
@@ -181,6 +181,10 @@ static const char *exe_name(void)
 {
 	ASSERT0(compiler.build.output_name || compiler.build.name || compiler.context.main || compiler.build.no_entry);
 	const char *name = out_name();
+	if (!name && compiler.build.no_entry)
+	{
+		name = "out";
+	}
 	if (!name)
 	{
 		Path *path = compiler.context.main->unit->module->name;
diff --git a/src/compiler/llvm_codegen.c b/src/compiler/llvm_codegen.c
index d310c345a..21fb27489 100644
--- a/src/compiler/llvm_codegen.c
+++ b/src/compiler/llvm_codegen.c
@@ -470,7 +470,7 @@ void llvm_set_global_tls(Decl *decl)
 
 static void llvm_set_weak(GenContext *c, LLVMValueRef global)
 {
-	LLVMSetLinkage(global, LLVMWeakAnyLinkage);
+	LLVMSetLinkage(global, compiler.platform.os == OS_TYPE_WIN32 ? LLVMWeakODRLinkage : LLVMWeakAnyLinkage);
 	LLVMSetVisibility(global, LLVMDefaultVisibility);
 	llvm_set_comdat(c, global);
 }
diff --git a/test/test_suite/functions/test_regression_mingw.c3t b/test/test_suite/functions/test_regression_mingw.c3t
index efd96f68e..8c9016495 100644
--- a/test/test_suite/functions/test_regression_mingw.c3t
+++ b/test/test_suite/functions/test_regression_mingw.c3t
@@ -625,7 +625,7 @@ entry:
 
 // #expect: foo.double.ll
 
-define weak double @"foo$double$.check"(double %0)
+define weak_odr double @"foo$double$.check"(double %0)
 entry:
   %fmul = fmul double %0, %0
   ret double %fmul
@@ -634,18 +634,18 @@ entry:
 // #expect: test2.int.ll
 
 %Blob = type { i32 }
-@"test2$int$.argh" = weak local_unnamed_addr global i32 234, comdat, align 4
+@"test2$int$.argh" = weak_odr local_unnamed_addr global i32 234, comdat, align 4
 
-define weak i32 @"test2$int$.getMult"(i32 %0)
+define weak_odr i32 @"test2$int$.getMult"(i32 %0)
 entry:
   %mul = mul i32 %0, %0
   ret i32 %mul
 
-define weak i32 @"test2$int$.hello"()
+define weak_odr i32 @"test2$int$.hello"()
 entry:
   ret i32 1
 }
-define weak i32 @"test2$int$.getValue"(i32 %0)
+define weak_odr i32 @"test2$int$.getValue"(i32 %0)
 entry:
   %blob = alloca %Blob, align 4
   store i32 %0, ptr %blob, align 4
@@ -658,19 +658,19 @@ entry:
 %Blob = type { double }
 
 
-@"test2$double$.argh" = weak local_unnamed_addr global double 2.340000e+02, comdat, align 8
+@"test2$double$.argh" = weak_odr local_unnamed_addr global double 2.340000e+02, comdat, align 8
 
-define weak double @"test2$double$.getMult"(double %0) #0 comdat {
+define weak_odr double @"test2$double$.getMult"(double %0) #0 comdat {
 entry:
   %fmul = fmul double %0, %0
   ret double %fmul
 
-define weak i32 @"test2$double$.hello"() #0 comdat {
+define weak_odr i32 @"test2$double$.hello"() #0 comdat {
 entry:
   ret i32 1
 }
 
-define weak double @"test2$double$.getValue"(i64 %0) #0 comdat {
+define weak_odr double @"test2$double$.getValue"(i64 %0) #0 comdat {
 entry:
   %blob = alloca %Blob, align 8
   store i64 %0, ptr %blob, align 8