From a8932910d9cc2201214b3a0dc730c67765ede20f Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Wed, 25 Sep 2024 21:01:00 +0200
Subject: [PATCH] wasm32 / wasm64 targets are use-libc=no by default.

---
 .github/workflows/main.yml |  4 ++--
 releasenotes.md            |  1 +
 src/build/builder.c        | 41 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b95a98cb2..0931b25ba 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -324,7 +324,7 @@ jobs:
       - name: Test WASM
         run: |
           cd resources/testfragments
-          ../../build/c3c compile --reloc=none --target wasm32 -g0 --link-libc=no --no-entry -Os wasm4.c3
+          ../../build/c3c compile --target wasm32 -g0 --no-entry -Os wasm4.c3
 
       - name: Install QEMU and Risc-V toolchain
         run: |
@@ -558,7 +558,7 @@ jobs:
       - name: Test WASM
         run: |
           cd resources/testfragments
-          ../../build/c3c compile --reloc=none --target wasm32 -g0 --link-libc=no --no-entry -Os wasm4.c3
+          ../../build/c3c compile --reloc=none --target wasm32 -g0 --no-entry -Os wasm4.c3
 
       - name: Build testproject direct linker
         run: |
diff --git a/releasenotes.md b/releasenotes.md
index 52e88fa05..38b59acc1 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -26,6 +26,7 @@
 - Deprecated inline generic types outside of struct definitions and macros unless marked `@adhoc`.
 - Improved method detection in earlier stages of checking.
 - Allow `^` suffix for non-recursive imports #1480.
+- wasm32 / wasm64 targets are use-libc=no by default.
 
 ### Fixes
 - Issue where a lambda wasn't correctly registered as external. #1408
diff --git a/src/build/builder.c b/src/build/builder.c
index 74f75c2a7..558818d7e 100644
--- a/src/build/builder.c
+++ b/src/build/builder.c
@@ -229,6 +229,43 @@ void update_build_target_with_opt_level(BuildTarget *target, OptimizationSetting
 	COPY_IF_DEFAULT(target->single_module, single_module);
 }
 
+static LinkLibc libc_from_arch_os(ArchOsTarget target)
+{
+	switch (target)
+	{
+		case ANDROID_AARCH64:
+		case FREEBSD_X86:
+		case FREEBSD_X64:
+		case IOS_AARCH64:
+		case LINUX_AARCH64:
+		case LINUX_RISCV32:
+		case LINUX_RISCV64:
+		case LINUX_X86:
+		case LINUX_X64:
+		case MACOS_AARCH64:
+		case MACOS_X64:
+		case MINGW_X64:
+		case NETBSD_X86:
+		case NETBSD_X64:
+		case OPENBSD_X86:
+		case OPENBSD_X64:
+		case WINDOWS_AARCH64:
+		case WINDOWS_X64:
+			return LINK_LIBC_ON;
+		case WASM32:
+		case WASM64:
+		case MCU_X86:
+		case ARCH_OS_TARGET_DEFAULT:
+		case ELF_AARCH64:
+		case ELF_RISCV32:
+		case ELF_RISCV64:
+		case ELF_X86:
+		case ELF_X64:
+		case ELF_XTENSA:
+			return LINK_LIBC_OFF;
+	}
+	UNREACHABLE
+}
 
 static void update_build_target_from_options(BuildTarget *target, BuildOptions *options)
 {
@@ -470,6 +507,10 @@ static void update_build_target_from_options(BuildTarget *target, BuildOptions *
 	}
 	if (target->optsetting == OPT_SETTING_NOT_SET) target->optsetting = OPT_SETTING_O0;
 	update_build_target_with_opt_level(target, target->optsetting);
+	if (target->link_libc == LINK_LIBC_NOT_SET)
+	{
+		target->link_libc = libc_from_arch_os(target->arch_os_target);
+	}
 }
 
 void init_default_build_target(BuildTarget *target, BuildOptions *options)