[x86] Allow address-size overrides for STOS[BWLQ] (PR9385)

[oota-llvm.git] / docs / CodeGenerator.rst

diff --git a/docs/CodeGenerator.rst b/docs/CodeGenerator.rst
index 1f2dc6ca7f7f40035aa8a0873aa8e1341a3b3d3e..b89d2f426f388a25cb206b4095246ff33d2a8707 100644 (file)
--- a/docs/CodeGenerator.rst
+++ b/docs/CodeGenerator.rst
@@ -434,12 +434,12 @@ For example, consider this simple LLVM example:
 .. code-block:: llvm
 
   define i32 @test(i32 %X, i32 %Y) {
 .. code-block:: llvm
 
   define i32 @test(i32 %X, i32 %Y) {

-    %Z = udiv i32 %X, %Y
+    %Z = sdiv i32 %X, %Y

     ret i32 %Z
   }
 
     ret i32 %Z
   }
 

-The X86 instruction selector produces this machine code for the ``div`` and
-``ret`` (use "``llc X.bc -march=x86 -print-machineinstrs``" to get this):
+The X86 instruction selector might produce this machine code for the ``div`` and
+``ret``:

 
 .. code-block:: llvm
 
 
 .. code-block:: llvm
 


@@ -454,8 +454,8 @@ The X86 instruction selector produces this machine code for the ``div`` and
   %EAX = mov %reg1026           ;; 32-bit return value goes in EAX
   ret
 
   %EAX = mov %reg1026           ;; 32-bit return value goes in EAX
   ret
 

-By the end of code generation, the register allocator has coalesced the
-registers and deleted the resultant identity moves producing the following
+By the end of code generation, the register allocator would coalesce the
+registers and delete the resultant identity moves producing the following

 code:
 
 .. code-block:: llvm
 code:
 
 .. code-block:: llvm


@@ -636,6 +636,18 @@ file (MCObjectStreamer).  MCAsmStreamer is a straight-forward implementation
 that prints out a directive for each method (e.g. ``EmitValue -> .byte``), but
 MCObjectStreamer implements a full assembler.
 
 that prints out a directive for each method (e.g. ``EmitValue -> .byte``), but
 MCObjectStreamer implements a full assembler.
 

+For target specific directives, the MCStreamer has a MCTargetStreamer instance.
+Each target that needs it defines a class that inherits from it and is a lot
+like MCStreamer itself: It has one method per directive and two classes that
+inherit from it, a target object streamer and a target asm streamer. The target
+asm streamer just prints it (``emitFnStart -> .fnstrart``), and the object
+streamer implement the assembler logic for it.
+
+To make llvm use these classes, the target initialization must call
+TargetRegistry::RegisterAsmStreamer and TargetRegistry::RegisterMCObjectStreamer
+passing callbacks that allocate the corresponding target streamer and pass it
+to createAsmStreamer or to the appropriate object streamer constructor.
+

 The ``MCContext`` class
 -----------------------
 
 The ``MCContext`` class
 -----------------------
 


@@ -1614,7 +1626,7 @@ Implementing a Native Assembler
 ===============================
 
 Though you're probably reading this because you want to write or maintain a
 ===============================
 
 Though you're probably reading this because you want to write or maintain a

-compiler backend, LLVM also fully supports building a native assemblers too.
+compiler backend, LLVM also fully supports building a native assembler.

 We've tried hard to automate the generation of the assembler from the .td files
 (in particular the instruction syntax and encodings), which means that a large
 part of the manual and repetitive data entry can be factored and shared with the
 We've tried hard to automate the generation of the assembler from the .td files
 (in particular the instruction syntax and encodings), which means that a large
 part of the manual and repetitive data entry can be factored and shared with the