From ef4aca2dc4224d0de1ab15112097fd48930476db Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Mon, 28 Feb 2022 16:12:01 +0200
Subject: stage2: implement `@extern`

---
 src/codegen/llvm.zig          | 18 ++++++++++++++++--
 src/codegen/llvm/bindings.zig | 11 +++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

(limited to 'src/codegen')

diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index fa29a1aae3..5ef62aadcb 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -548,6 +548,10 @@ pub const Object = struct {
             llvm_global.setValueName(decl.name);
             llvm_global.setUnnamedAddr(.False);
             llvm_global.setLinkage(.External);
+            if (decl.val.castTag(.variable)) |variable| {
+                if (variable.data.is_threadlocal) llvm_global.setThreadLocalMode(.GeneralDynamicTLSModel);
+                if (variable.data.is_weak_linkage) llvm_global.setLinkage(.ExternalWeak);
+            }
         } else if (exports.len != 0) {
             const exp_name = exports[0].options.name;
             llvm_global.setValueName2(exp_name.ptr, exp_name.len);
@@ -558,6 +562,9 @@ pub const Object = struct {
                 .Weak => llvm_global.setLinkage(.WeakODR),
                 .LinkOnce => llvm_global.setLinkage(.LinkOnceODR),
             }
+            if (decl.val.castTag(.variable)) |variable| {
+                if (variable.data.is_threadlocal) llvm_global.setThreadLocalMode(.GeneralDynamicTLSModel);
+            }
             // If a Decl is exported more than one time (which is rare),
             // we add aliases for all but the first export.
             // TODO LLVM C API does not support deleting aliases. We need to
@@ -788,8 +795,15 @@ pub const DeclGen = struct {
         const llvm_global = dg.object.llvm_module.addGlobalInAddressSpace(llvm_type, fqn, llvm_addrspace);
         gop.value_ptr.* = llvm_global;
 
-        const is_extern = decl.val.tag() == .unreachable_value;
-        if (!is_extern) {
+        if (decl.isExtern()) {
+            llvm_global.setValueName(decl.name);
+            llvm_global.setUnnamedAddr(.False);
+            llvm_global.setLinkage(.External);
+            if (decl.val.castTag(.variable)) |variable| {
+                if (variable.data.is_threadlocal) llvm_global.setThreadLocalMode(.GeneralDynamicTLSModel);
+                if (variable.data.is_weak_linkage) llvm_global.setLinkage(.ExternalWeak);
+            }
+        } else {
             llvm_global.setLinkage(.Internal);
             llvm_global.setUnnamedAddr(.True);
         }
diff --git a/src/codegen/llvm/bindings.zig b/src/codegen/llvm/bindings.zig
index c505a7d045..a3f7ff9561 100644
--- a/src/codegen/llvm/bindings.zig
+++ b/src/codegen/llvm/bindings.zig
@@ -120,6 +120,9 @@ pub const Value = opaque {
     pub const setUnnamedAddr = LLVMSetUnnamedAddr;
     extern fn LLVMSetUnnamedAddr(Global: *const Value, HasUnnamedAddr: Bool) void;
 
+    pub const setThreadLocalMode = LLVMSetThreadLocalMode;
+    extern fn LLVMSetThreadLocalMode(Global: *const Value, Mode: ThreadLocalMode) void;
+
     pub const deleteGlobal = LLVMDeleteGlobal;
     extern fn LLVMDeleteGlobal(GlobalVar: *const Value) void;
 
@@ -1230,6 +1233,14 @@ pub const Linkage = enum(c_uint) {
     LinkerPrivateWeak,
 };
 
+pub const ThreadLocalMode = enum(c_uint) {
+    NotThreadLocal,
+    GeneralDynamicTLSModel,
+    LocalDynamicTLSModel,
+    InitialExecTLSModel,
+    LocalExecTLSModel,
+};
+
 pub const AtomicOrdering = enum(c_uint) {
     NotAtomic = 0,
     Unordered = 1,
-- 
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