Add LLVM function declarations

3 files changed, 26 insertions, 1 deletions

diff --git a/src/main/java/org/shedlang/compiler/backends/llvm/ir/LlvmIrSerializer.java b/src/main/java/org/shedlang/compiler/backends/llvm/ir/LlvmIrSerializer.java
index 74a271ed..0b1ff62b 100644
--- a/src/main/java/org/shedlang/compiler/backends/llvm/ir/LlvmIrSerializer.java
+++ b/src/main/java/org/shedlang/compiler/backends/llvm/ir/LlvmIrSerializer.java
@@ -180,6 +180,19 @@ public class LlvmIrSerializer {
 
     public static void serializeTopLevelEntity(LlvmTopLevelEntity entity, StringBuilder builder) {
         switch (entity) {
+            case LlvmFunctionDeclaration functionDeclaration -> {
+                builder.append("declare ");
+                serializeType(functionDeclaration.returnType(), builder);
+                builder.append(" @");
+                builder.append(functionDeclaration.name());
+                builder.append("(");
+                forEachInterspersed(
+                    functionDeclaration.params(),
+                    param -> serializeParam(param, builder),
+                    () -> builder.append(", ")
+                );
+                builder.append(")\n");
+            }
             case LlvmFunctionDefinition functionDefinition -> {
                 builder.append("define ");
                 serializeType(functionDefinition.returnType(), builder);
diff --git a/src/main/java/org/shedlang/compiler/backends/llvm/ir/ast/LlvmFunctionDeclaration.java b/src/main/java/org/shedlang/compiler/backends/llvm/ir/ast/LlvmFunctionDeclaration.java
new file mode 100644
index 00000000..4abd406c
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/backends/llvm/ir/ast/LlvmFunctionDeclaration.java
@@ -0,0 +1,12 @@
+package org.shedlang.compiler.backends.llvm.ir.ast;
+
+import org.shedlang.compiler.backends.llvm.ir.ast.types.LlvmType;
+
+import java.util.List;
+
+public record LlvmFunctionDeclaration(
+    String name,
+    LlvmType returnType,
+    List<LlvmParam> params
+) implements LlvmTopLevelEntity {
+}
diff --git a/src/main/java/org/shedlang/compiler/backends/llvm/ir/ast/LlvmTopLevelEntity.java b/src/main/java/org/shedlang/compiler/backends/llvm/ir/ast/LlvmTopLevelEntity.java
index b1cabfa0..376664f2 100644
--- a/src/main/java/org/shedlang/compiler/backends/llvm/ir/ast/LlvmTopLevelEntity.java
+++ b/src/main/java/org/shedlang/compiler/backends/llvm/ir/ast/LlvmTopLevelEntity.java
@@ -1,5 +1,5 @@
 package org.shedlang.compiler.backends.llvm.ir.ast;
 
-public sealed interface LlvmTopLevelEntity permits LlvmFunctionDefinition, LlvmGlobalDefinition {
+public sealed interface LlvmTopLevelEntity permits LlvmFunctionDeclaration, LlvmFunctionDefinition, LlvmGlobalDefinition {
     String name();
 }