diff --git a/src/environment/llvm-prefix.ts b/src/environment/llvm-prefix.ts
deleted file mode 100644
index 1af4b92..0000000
--- a/src/environment/llvm-prefix.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-import path from "path";
-
-export interface Toolchain {
-    /**
-     * C compiler.
-     */
-    CC: string;
-
-    /**
-     * C++ compiler.
-     */
-    CXX: string;
-
-    /**
-     * Fortran compiler.
-     */
-    FC: string;
-};
-
-export function llvmToolchain(prefix: string) {
-    const bin = path.resolve(prefix, "bin");
-    return {
-        CC: path.resolve(bin, "clang"),
-        CXX: path.resolve(bin, "clang++"),
-        FC: path.resolve(bin, "flang"),
-        LLVM_EXTRACT: path.resolve(bin, "llvm-extract"),
-    };
-}
diff --git a/src/toolchain/index.ts b/src/toolchain/index.ts
new file mode 100644
index 0000000..9098a0e
--- /dev/null
+++ b/src/toolchain/index.ts
@@ -0,0 +1,115 @@
+import { spawn } from 'child_process';
+import { promisifySpawn } from 'lyc/cli';
+import { generalCommand, extractCommand } from 'lyc/commands/compiler';
+import path from 'path';
+
+export interface Toolchain {
+    /**
+     * C compiler.
+     */
+    CC: string;
+
+    /**
+     * C++ compiler.
+     */
+    CXX: string;
+
+    /**
+     * Fortran compiler.
+     */
+    FC: string;
+};
+
+export interface LLVMToolchain extends Toolchain {
+    /**
+     * An llvm tooling that may extract part of LLVM IR.
+     */
+    LLVM_EXTRACT: string;
+}
+
+export function llvmToolchain(prefix: string) {
+    const bin = path.resolve(prefix, "bin");
+    return {
+        CC: path.resolve(bin, "clang"),
+        CXX: path.resolve(bin, "clang++"),
+        FC: path.resolve(bin, "flang"),
+        LLVM_EXTRACT: path.resolve(bin, "llvm-extract"),
+    };
+}
+
+/**
+ * Give an LLVM toolchain, and a desired IR, a list of function names.
+ * Generate a function that takes vFnPath and sFnPath, used for path calculation.
+ */
+export function reduceIR(llvmTC: LLVMToolchain, IR: string) {
+    const objFlags = [
+        ...generalCommand({
+            outputKind: 'object',
+        }),
+        '-x', 'ir',
+        // Read from stdin.
+        '-',
+    ];
+
+    return {
+        mkFnObjects: async (fnList: string[], vFnPath: (fn: string) => string, sFnPath: (fn: string) => string) => {
+            // Parse the IR with all function names
+            // For each function, extract it.
+            await Promise.all(fnList.map(fn => {
+                const proc = spawn(llvmTC.LLVM_EXTRACT, [
+                    ...extractCommand({
+                        func: [fn],
+                        asm: true,
+                        input: '-',
+                        output: '-',
+                    }),
+                ]);
+
+                // Write IR and close stdin
+                proc.stdin.write(IR);
+                proc.stdin.end();
+
+                const compileVector = spawn(llvmTC.FC, [
+                    ...objFlags,
+                    ...generalCommand({ output: vFnPath(fn), }),
+                    '-msimd',
+                ]);
+
+                const compileScalar = spawn(llvmTC.FC, [
+                    ...objFlags,
+                    ...generalCommand({ output: sFnPath(fn) }),
+                ]);
+
+                proc.stdout.pipe(compileVector.stdin);
+                proc.stdout.pipe(compileScalar.stdin);
+
+                return Promise.all([proc, compileScalar, compileScalar].map(promisifySpawn));
+            }));
+        },
+        mkGlobalObject: async (globalPath: string) => {
+            const proc = spawn(llvmTC.LLVM_EXTRACT, [
+                ...extractCommand({
+                    asm: true,
+                    input: "-",
+                    output: "-",
+                }),
+                // Extract all global variables.
+                "-rglob",
+                ".*",
+            ], { stdio: ['pipe', 'pipe', 'inherit'] });
+
+            // Write IR and close stdin
+            proc.stdin.write(IR);
+            proc.stdin.end();
+
+            const compileScalar = spawn(llvmTC.FC, [
+                ...objFlags,
+                ...generalCommand({ output: globalPath }),
+            ], { stdio: ['pipe', 'inherit', 'inherit'] });
+
+            proc.stdout.pipe(compileScalar.stdin);
+
+            return Promise.all([proc, compileScalar].map(promisifySpawn));
+        }
+    };
+}