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copied!<p>For top level declarations, it's not too hard. Local definitions can be harder to recognize as their names get mangled and they are likely to get inlined.</p> <p>Let's see what happens when we compile this simple module.</p> <pre class="lang-hs prettyprint-override"><code>module Example where add :: Int -> Int -> Int add x y = x + y </code></pre> <pre class="lang-asm prettyprint-override"><code><strong>.data .align 8 .globl Example_add_closure .type Example_add_closure, @object Example_add_closure: .quad Example_add_info .text .align 8 .quad 8589934604 .quad 0 .quad 15 .globl Example_add_info .type Example_add_info, @object Example_add_info: .LckX: jmp base_GHCziBase_plusInt_info</strong> .data .align 8 _module_registered: .quad 0 .text .align 8 .globl __stginit_Example_ .type __stginit_Example_, @object __stginit_Example_: .Lcl7: cmpq $0,_module_registered jne .Lcl8 .Lcl9: movq $1,_module_registered addq $-8,%rbp movq $__stginit_base_Prelude_,(%rbp) .Lcl8: addq $8,%rbp jmp *-8(%rbp) .text .align 8 .globl __stginit_Example .type __stginit_Example, @object __stginit_Example: .Lcld: jmp __stginit_Example_ .section .note.GNU-stack,"",@progbits .ident "GHC 7.0.2" </code></pre> <p>You can see that our function <code>Example.add</code> resulted in the generation of <code>Example_add_closure</code> and <code>Example_add_info</code>. The <code>_closure</code> part, as the name suggests, has to do with closures. The <code>_info</code> part contains the actual instructions of the function. In this case, this is simply a jump to the built-in function <code>GHC.Base.plusInt</code>. </p> <p>Note that assembly generated from Haskell code looks quite different from what you might get from other languages. The calling conventions are different, and things can get reordered a lot.</p> <p>In most cases you don't want to jump straight to assembly. It is usually much easier to understand <em>core</em>, a simplified version of Haskell. (Simpler to compile, not necessarily to read). To get at the core, compile with the <code>-ddump-simpl</code> option.</p> <pre class="lang-none prettyprint-override"><code>Example.add :: GHC.Types.Int -> GHC.Types.Int -> GHC.Types.Int [GblId, Arity=2] Example.add = \ (x_abt :: GHC.Types.Int) (y_abu :: GHC.Types.Int) -> GHC.Num.+ @ GHC.Types.Int GHC.Num.$fNumInt x_abt y_abu </code></pre> <p>For some good resources on how to read core, see <a href="https://stackoverflow.com/questions/6121146/reading-ghc-core/6121495#6121495">this question</a>.</p>

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