diff --git a/deps/LLVMExtra/include/LLVMExtra.h b/deps/LLVMExtra/include/LLVMExtra.h
index 543c2c14..cf6f61b5 100644
--- a/deps/LLVMExtra/include/LLVMExtra.h
+++ b/deps/LLVMExtra/include/LLVMExtra.h
@@ -4,6 +4,10 @@
 #include "llvm/Config/llvm-config.h"
 #include <llvm-c/Core.h>
 #include <llvm-c/Types.h>
+typedef struct LLVMOpaqueTargetMachine *LLVMTargetMachineRef;
+// Can't include TargetMachine since that would inclue LLVMInitializeNativeTarget
+// #include <llvm-c/TargetMachine.h>
+#include <llvm-c/Transforms/PassManagerBuilder.h>
 
 LLVM_C_EXTERN_C_BEGIN
 
@@ -159,6 +163,29 @@ LLVMValueRef LLVMBuildCallWithOpBundle(LLVMBuilderRef B, LLVMValueRef Fn,
                                        LLVMValueRef *Args, unsigned NumArgs,
                                        LLVMOperandBundleDefRef *Bundles, unsigned NumBundles,
                                        const char *Name);
+void LLVMAdjustPassManager(LLVMTargetMachineRef TM, LLVMPassManagerBuilderRef PMB);
+
+typedef void (*LLVMPassManagerBuilderExtensionFunction)(
+    void *Ctx, LLVMPassManagerBuilderRef PMB, LLVMPassManagerRef PM);
+
+typedef enum {
+    EP_EarlyAsPossible,
+    EP_ModuleOptimizerEarly,
+    EP_LoopOptimizerEnd,
+    EP_ScalarOptimizerLate,
+    EP_OptimizerLast,
+    EP_VectorizerStart,
+    EP_EnabledOnOptLevel0,
+    EP_Peephole,
+    EP_LateLoopOptimizations,
+    EP_CGSCCOptimizerLate,
+    EP_FullLinkTimeOptimizationEarly,
+    EP_FullLinkTimeOptimizationLast,
+} LLVMPassManagerBuilderExtensionPointTy;
+
+void LLVMPassManagerBuilderAddExtension(LLVMPassManagerBuilderRef PMB,
+                                        LLVMPassManagerBuilderExtensionPointTy Ty,
+                                        LLVMPassManagerBuilderExtensionFunction Fn, void *Ctx);
 
 LLVM_C_EXTERN_C_END
 #endif
diff --git a/deps/LLVMExtra/lib/llvm-api.cpp b/deps/LLVMExtra/lib/llvm-api.cpp
index c937dac5..ce7ff270 100644
--- a/deps/LLVMExtra/lib/llvm-api.cpp
+++ b/deps/LLVMExtra/lib/llvm-api.cpp
@@ -21,6 +21,8 @@
 #endif
 #include <llvm/Transforms/Utils/Cloning.h>
 #include <llvm/Transforms/Utils/ModuleUtils.h>
+#include <llvm/Target/TargetMachine.h>
+#include <llvm/Transforms/IPO/PassManagerBuilder.h>
 
 using namespace llvm;
 using namespace llvm::legacy;
@@ -548,3 +550,17 @@ LLVMValueRef LLVMBuildCallWithOpBundle(LLVMBuilderRef B, LLVMValueRef Fn,
     return wrap(unwrap(B)->CreateCall(FnT, unwrap(Fn), makeArrayRef(unwrap(Args), NumArgs),
                                       BundleArray, Name));
 }
+
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(TargetMachine, LLVMTargetMachineRef)
+void LLVMAdjustPassManager(LLVMTargetMachineRef TM, LLVMPassManagerBuilderRef PMB) {
+  unwrap(TM)->adjustPassManager(*unwrap(PMB));
+}
+
+void LLVMPassManagerBuilderAddExtension(LLVMPassManagerBuilderRef PMB,
+                                        LLVMPassManagerBuilderExtensionPointTy Ty,
+                                        LLVMPassManagerBuilderExtensionFunction Fn, void *Ctx) {
+  PassManagerBuilder &Builder = *unwrap(PMB);
+  Builder.addExtension((PassManagerBuilder::ExtensionPointTy)Ty,
+    [&](const PassManagerBuilder &Builder, legacy::PassManagerBase &PM) {
+        Fn(Ctx, wrap(const_cast<PassManagerBuilder*>(&Builder)), wrap(&PM)); });
+}
\ No newline at end of file
diff --git a/lib/libLLVM_extra.jl b/lib/libLLVM_extra.jl
index e739b5f1..baa57c08 100644
--- a/lib/libLLVM_extra.jl
+++ b/lib/libLLVM_extra.jl
@@ -419,3 +419,28 @@ function LLVMBuildCallWithOpBundle(B, Fn, Args, NumArgs, Bundles, NumBundles, Na
     ccall((:LLVMBuildCallWithOpBundle, libLLVMExtra), LLVMValueRef, (LLVMBuilderRef, LLVMValueRef, Ptr{LLVMValueRef}, Cuint, Ptr{LLVMOperandBundleDefRef}, Cuint, Cstring), B, Fn, Args, NumArgs, Bundles, NumBundles, Name)
 end
 
+function LLVMAdjustPassManager(TM, PMB)
+    ccall((:LLVMAdjustPassManager, libLLVMExtra), Cvoid, (LLVMTargetMachineRef, LLVMPassManagerBuilderRef), TM, PMB)
+end
+
+const LLVMPassManagerBuilderExtensionFunction = Ptr{Cvoid}
+
+# See llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h
+@cenum LLVMPassManagerBuilderExtensionPointTy::UInt32 begin
+    EP_EarlyAsPossible = 0
+    EP_ModuleOptimizerEarly = 1
+    EP_LoopOptimizerEnd = 2
+    EP_ScalarOptimizerLate = 3
+    EP_OptimizerLast = 4
+    EP_VectorizerStart = 5
+    EP_EnabledOnOptLevel0 = 6
+    EP_Peephole = 7
+    EP_LateLoopOptimizations= 8
+    EP_CGSCCOptimizerLate = 9
+    EP_FullLinkTimeOptimizationEarly = 10
+    EP_FullLinkTimeOptimizationLast = 11
+end
+
+function LLVMPassManagerBuilderAddExtension(PMB, Ty, Fn, Ctx)
+    ccall((:LLVMPassManagerBuilderAddExtension, libLLVMExtra), Cvoid, (LLVMPassManagerBuilderRef, LLVMPassManagerBuilderExtensionPointTy, LLVMPassManagerBuilderExtensionFunction, Ptr{Cvoid}), PMB, Ty, Fn, Ctx)
+end
\ No newline at end of file
diff --git a/src/targetmachine.jl b/src/targetmachine.jl
index ee3899d6..f1232abb 100644
--- a/src/targetmachine.jl
+++ b/src/targetmachine.jl
@@ -18,6 +18,12 @@ TargetMachine(t::Target, triple::String, cpu::String="", features::String="";
     TargetMachine(API.LLVMCreateTargetMachine(t, triple, cpu, features, optlevel,
                                               reloc, code))
 
+function TargetMachine()
+    host_triple = triple()
+    host_t = Target(triple=host_triple)
+    TargetMachine(host_t, host_triple)
+end
+
 dispose(tm::TargetMachine) = API.LLVMDisposeTargetMachine(tm)
 
 function TargetMachine(f::Core.Function, args...; kwargs...)
diff --git a/src/transform.jl b/src/transform.jl
index c8d395b9..93f06144 100644
--- a/src/transform.jl
+++ b/src/transform.jl
@@ -3,11 +3,17 @@
 export PassManagerBuilder, dispose,
        optlevel!, sizelevel!,
        unit_at_a_time!, unroll_loops!, simplify_libcalls!, inliner!,
-       populate!
+       populate!, adjust!, extend!
+
+mutable struct Callback
+    fn
+end
 
 @checked struct PassManagerBuilder
     ref::API.LLVMPassManagerBuilderRef
+    rooted::Vector{Callback}
 end
+PassManagerBuilder(ref) = PassManagerBuilder(ref, Callback[])
 
 Base.unsafe_convert(::Type{API.LLVMPassManagerBuilderRef}, pmb::PassManagerBuilder) = pmb.ref
 
@@ -50,6 +56,23 @@ populate!(fpm::FunctionPassManager, pmb::PassManagerBuilder) =
 populate!(mpm::ModulePassManager, pmb::PassManagerBuilder) =
     API.LLVMPassManagerBuilderPopulateModulePassManager(pmb, mpm)
 
+adjust!(pmb::PassManagerBuilder, tm::TargetMachine) =
+    API.LLVMAdjustPassManager(tm, pmb)
+
+function extend_callback(ctx, pmb, pm)
+    cb = Base.unsafe_pointer_to_objref(ctx)
+    cb.fn(PassManagerBuilder(pmb), PassManager(pm))
+    return nothing
+end
+
+function extend!(pmb::PassManagerBuilder, ep, fn)
+    cb = Callback(fn)
+    push!(pmb.rooted, cb) # root through pmb
+    c_cb = @cfunction(extend_callback, Cvoid, (Ptr{Cvoid}, API.LLVMPassManagerBuilderRef, API.LLVMPassManagerRef))
+    API.LLVMPassManagerBuilderAddExtension(pmb, ep, c_cb, Base.pointer_from_objref(cb))
+end
+
+extend!(fn, pmb::PassManagerBuilder, ep) = extend!(pmb, ep, fn)
 
 ## auxiliary
 
diff --git a/test/transform.jl b/test/transform.jl
index f91b262d..3ccefbab 100644
--- a/test/transform.jl
+++ b/test/transform.jl
@@ -14,6 +14,14 @@ PassManagerBuilder() do pmb
     simplify_libcalls!(pmb, false)
     inliner!(pmb, 0)
 
+    TargetMachine() do tm
+        adjust!(pmb, tm)
+    end
+
+    extend!(pmb, LLVM.API.EP_EarlyAsPossible) do pmb, pm
+        verifier!(pm)
+    end
+
     Context() do ctx
     LLVM.Module("SomeModule"; ctx) do mod
         FunctionPassManager(mod) do fpm