Object-based iteration for module flags.

Author: maleadt

src/core/instructions.jl

@@ -45,6 +45,7 @@ predicate_real(inst::Instruction) = API.LLVMGetFCmpPredicate(ref(inst))
 
 
 ## metadata iteration
+# TODO: doesn't actually iterate, since we can't list the available keys
 
 @enum(MD, MD_dbg = 0,
           MD_tbaa = 1,
@@ -72,8 +73,6 @@ predicate_real(inst::Instruction) = API.LLVMGetFCmpPredicate(ref(inst))
 
 export InstructionMetadataDict
 
-# doesn't print, because we don't have length. we can't iterate keys?
-
 struct InstructionMetadataDict <: AbstractDict{MD,MetadataAsValue}
     inst::Instruction
 end

src/core/module.jl

@@ -177,7 +177,30 @@ function Base.getindex(iter::ModuleFunctionSet, name::String)
     return Function(objref)
 end
 
-# flags
+
+## module flag iteration
+# TODO: doesn't actually iterate, since we can't list the available keys
+
 if libllvm_version >= v"8.0"
-addflag!(mod::Module, behavior, key, val) = LLVM.API.LLVMAddModuleFlag(ref(mod), behavior, key, length(key), LLVM.ref(Metadata(val)))
+
+export flags
+
+struct ModuleFlagDict <: AbstractDict{String,Metadata}
+    mod::Module
+end
+
+flags(mod::Module) = ModuleFlagDict(mod)
+
+Base.haskey(iter::ModuleFlagDict, name::String) =
+    API.LLVMGetModuleFlag(ref(iter.mod), name, length(name)) != C_NULL
+
+function Base.getindex(iter::ModuleFlagDict, name::String)
+    objref = API.LLVMGetModuleFlag(ref(iter.mod), name, length(name))
+    objref == C_NULL && throw(KeyError(name))
+    return Metadata(objref)
+end
+
+Base.push!(iter::ModuleFlagDict, behavior::LLVM.API.LLVMModuleFlagBehavior, name::String, val::Metadata) =
+    API.LLVMAddModuleFlag(ref(iter.mod), behavior, name, length(name), ref(val))
+
 end

test/core.jl

@@ -528,6 +528,19 @@ LLVM.Module("SomeModule", ctx) do mod
     dummyLayout = "e-p:64:64:64"
     datalayout!(mod, dummyLayout)
     @test convert(String, datalayout(mod)) == dummyLayout
+
+    if LLVM.version() >= v"8.0"
+        md = Metadata(ConstantInt(42))
+
+        mod_flags = flags(mod)
+        push!(mod_flags, LLVM.API.LLVMModuleFlagBehaviorError, "foobar", md)
+
+        @test occursin("!llvm.module.flags = !{!0}", sprint(io->show(io,mod)))
+        @test occursin(r"!0 = !\{i\d+ 1, !\"foobar\", i\d+ 42\}", sprint(io->show(io,mod)))
+
+        @test mod_flags["foobar"] == md
+        @test_throws KeyError mod_flags["foobaz"]
+    end
 end
 end