From e2345f006ffcd17e41aa73b27890044a0e1f2218 Mon Sep 17 00:00:00 2001
From: antlilja <liljaanton2001@gmail.com>
Date: Sat, 2 Mar 2024 15:19:09 +0100
Subject: [PATCH 1/3] LLVM: Add enableBrokenDebugInfoCheck and
 getBrokenDebugInfo

These functions allows the caller to find out wether the context
encounters broken debug info or not.
---
 src/codegen/llvm/bindings.zig |  6 ++++++
 src/zig_llvm.cpp              | 20 ++++++++++++++++++++
 src/zig_llvm.h                |  3 +++
 3 files changed, 29 insertions(+)

diff --git a/src/codegen/llvm/bindings.zig b/src/codegen/llvm/bindings.zig
index affadef882..ee87aef6ac 100644
--- a/src/codegen/llvm/bindings.zig
+++ b/src/codegen/llvm/bindings.zig
@@ -37,6 +37,12 @@ pub const Context = opaque {
 
     pub const setOptBisectLimit = ZigLLVMSetOptBisectLimit;
     extern fn ZigLLVMSetOptBisectLimit(C: *Context, limit: c_int) void;
+
+    pub const enableBrokenDebugInfoCheck = ZigLLVMEnableBrokenDebugInfoCheck;
+    extern fn ZigLLVMEnableBrokenDebugInfoCheck(C: *Context) void;
+
+    pub const getBrokenDebugInfo = ZigLLVMGetBrokenDebugInfo;
+    extern fn ZigLLVMGetBrokenDebugInfo(C: *Context) bool;
 };
 
 pub const Module = opaque {
diff --git a/src/zig_llvm.cpp b/src/zig_llvm.cpp
index e5432737f9..92364cc143 100644
--- a/src/zig_llvm.cpp
+++ b/src/zig_llvm.cpp
@@ -380,6 +380,26 @@ void ZigLLVMSetOptBisectLimit(LLVMContextRef context_ref, int limit) {
     unwrap(context_ref)->setOptPassGate(opt_bisect);
 }
 
+struct ZigDiagnosticHandler : public DiagnosticHandler {
+    bool BrokenDebugInfo;
+    ZigDiagnosticHandler() : BrokenDebugInfo(false) {}
+    bool handleDiagnostics(const DiagnosticInfo &DI) override {
+        if (auto *Remark = dyn_cast<DiagnosticInfoDebugMetadataVersion>(&DI)) {
+            BrokenDebugInfo = true;
+        }
+        return false;
+      }
+};
+
+void ZigLLVMEnableBrokenDebugInfoCheck(LLVMContextRef context_ref) {
+    unwrap(context_ref)->setDiagnosticHandler(std::make_unique<ZigDiagnosticHandler>());
+}
+
+bool ZigLLVMGetBrokenDebugInfo(LLVMContextRef context_ref) {
+    return ((const ZigDiagnosticHandler*)
+        unwrap(context_ref)->getDiagHandlerPtr())->BrokenDebugInfo;
+}
+
 void ZigLLVMParseCommandLineOptions(size_t argc, const char *const *argv) {
     cl::ParseCommandLineOptions(argc, argv);
 }
diff --git a/src/zig_llvm.h b/src/zig_llvm.h
index 56298e88bb..e133cb01b7 100644
--- a/src/zig_llvm.h
+++ b/src/zig_llvm.h
@@ -44,6 +44,9 @@ ZIG_EXTERN_C LLVMTargetMachineRef ZigLLVMCreateTargetMachine(LLVMTargetRef T, co
 
 ZIG_EXTERN_C void ZigLLVMSetOptBisectLimit(LLVMContextRef context_ref, int limit);
 
+ZIG_EXTERN_C void ZigLLVMEnableBrokenDebugInfoCheck(LLVMContextRef context_ref);
+ZIG_EXTERN_C bool ZigLLVMGetBrokenDebugInfo(LLVMContextRef context_ref);
+
 enum ZigLLVMTailCallKind {
     ZigLLVMTailCallKindNone,
     ZigLLVMTailCallKindTail,

From d345068ec2cf7275c931c4d79d46384c38132ffc Mon Sep 17 00:00:00 2001
From: antlilja <liljaanton2001@gmail.com>
Date: Sat, 2 Mar 2024 15:45:58 +0100
Subject: [PATCH 2/3] LLVM: Fail to emit if LLVM encounters broken debug info

---
 src/codegen/llvm.zig | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 82b204cacb..885b278607 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -1245,9 +1245,11 @@ pub const Object = struct {
             );
             defer bitcode_memory_buffer.dispose();
 
+            context.enableBrokenDebugInfoCheck();
+
             var module: *llvm.Module = undefined;
-            if (context.parseBitcodeInContext2(bitcode_memory_buffer, &module).toBool()) {
-                std.debug.print("Failed to parse bitcode\n", .{});
+            if (context.parseBitcodeInContext2(bitcode_memory_buffer, &module).toBool() or context.getBrokenDebugInfo()) {
+                log.err("Failed to parse bitcode", .{});
                 return error.FailedToEmit;
             }
             break :emit .{ context, module };

From 282b398f6da967f413e223b452457d37e93a70b3 Mon Sep 17 00:00:00 2001
From: antlilja <liljaanton2001@gmail.com>
Date: Sun, 3 Mar 2024 02:28:24 +0100
Subject: [PATCH 3/3] Add comment explaining LLVM bug and linking tracking
 issue

---
 src/zig_llvm.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/zig_llvm.cpp b/src/zig_llvm.cpp
index 92364cc143..ae1f02422b 100644
--- a/src/zig_llvm.cpp
+++ b/src/zig_llvm.cpp
@@ -384,6 +384,11 @@ struct ZigDiagnosticHandler : public DiagnosticHandler {
     bool BrokenDebugInfo;
     ZigDiagnosticHandler() : BrokenDebugInfo(false) {}
     bool handleDiagnostics(const DiagnosticInfo &DI) override {
+        // This dyn_cast should be casting to DiagnosticInfoIgnoringInvalidDebugMetadata
+        // but DiagnosticInfoIgnoringInvalidDebugMetadata is treated as DiagnosticInfoDebugMetadataVersion
+        // because of a bug in LLVM (see https://github.com/ziglang/zig/issues/19161).
+        // After this is fixed add an additional check for DiagnosticInfoIgnoringInvalidDebugMetadata
+        // but don't remove the current one as both indicate that debug info is broken.
         if (auto *Remark = dyn_cast<DiagnosticInfoDebugMetadataVersion>(&DI)) {
             BrokenDebugInfo = true;
         }