From 1c80fbfeca2cd5d871d905bed26aea4671ee8f3d Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 27 Nov 2011 20:51:47 +0000
Subject: [PATCH] distribute various bullets to different sections.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145196 91177308-0d34-0410-b5e6-96231b3b80d8
---
 docs/ReleaseNotes.html | 418 ++++++++++++++++++++++-------------------
 1 file changed, 222 insertions(+), 196 deletions(-)

diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html
index 7568575d9be..d756fb3576e 100644
--- a/docs/ReleaseNotes.html
+++ b/docs/ReleaseNotes.html
@@ -743,210 +743,54 @@ be used to verify some algorithms.
    loop dependence analysis
    CorrelatedValuePropagation
    lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
-   -->
+   Integrated assembler on by default for arm/thumb?
 
-<p><b>llvm-gcc is gone</b>.  LLVM's configure script doesn't depend on llvm-gcc anymore, clean layering.</p>
+   -->
 
-<p>LLVM 3.0 includes several major new capabilities:</p>
-  
-<!-- Near dead:
+  <!-- Near dead:
    Analysis/RegionInfo.h + Dom Frontiers
    SparseBitVector: used in LiveVar.
    llvm/lib/Archive - replace with lib object?
- -->
-  
-<!--
- Type system rewrite: http://blog.llvm.org/2011/11/llvm-30-type-system-rewrite.html
- Better performance for Neon code in clang due to SRoA improvements.
- New regalloc on by default. Lin scan going away in 3.1
- PGO / builtin_expect improvements (summary needed)
- Big EH rewrite.
- AVX support, assembler, compiler and disassembler.
- IndVar improvements: andy
- PTX backend improvements: Justin
- llvm-rtdyld & MC JIT: JimG
- InstAliases now automatically used in the asmprinter where they are shorter.
- Integrated assembler on by default for arm/thumb?
- PostOrder Dominator frontiers were removed.
- Line Profiling / gcov support
- EH and debug information produced with CFI directives, yielding smaller executables: http://blog.mozilla.com/respindola/2011/05/12/cfi-directives/
- X86-64 generates smaller and faster code at -O0 (fast isel improvements)
- Better code generation for Cortex-A9
- Many APIs take ArrayRef's now.
- Pass manager extension API.
- ARM inline asm constraints implemented.
- LangRef.html#fnattrs uwtable attribute for asynch unwind tables.
- better performance for indirect gotos.
- llvm.prefetch now takes a 4th argument that specifies whether the prefetch happens to the icache or dcache.
- New PackedVector, TinyPtrVector class (see Programmer's Manual)
- New nonlazybind function attribute.
- ARC language specific optimizer (Transforms/ObjCARC) a decent example of language-specific transformation.
- LLVM 3.0 removes support for reading LLVM 2.8 and earlier files.  Aim to maintain compatibility all the way back to 3.0 "forever".
-
- New llvm.expect intrinsic.
- Table generated MC expansion logic for pseudo instructions that expand to multiple MC instructions through the PseudoInstExpansion class. (JimG)
- New llvm.fma intrinsic.
- 
- Euro dev meeting and main one too.
- New atomics instructions, "#i_fence" instruction, cmpxchg, atomicrmw too.  What target support (X86/ARM)? Also 'atomic load/store'.  See Atomics.html
- X86: inline assembler supports .code32 and .code64.
- Exception handling rewrite: new landingpad and resume instruction.  Unwind gone.
- LowerSetJmp pass removed, unused.
- llvm-objdump / dwarf parser library / llvm-dwarfdump (d0k)
- object file parsing stuff and llvm-size (mspencer)
- llvm-cov (devang)
- Old arm disassembler replaced with a new one based on autogenerated encoding information from ARM .td files.
- Frontend tests removed from llvm/test/Frontend* (was this completed for 3.0?)
- Segmented stack support (X86 only?) Rafael and Sanjoy Das: docs/SegmentedStacks.html should be in CodeGen.html status table?
- X86 backend support for NaCl (David Meyer / Nick L)
- Codegen now supports vector "select" operations on vector comparisons, turning
-   them into various optimized code sequences (e.g. using the SSE4/AVX "blend"
-   instructions).
-  #line directives in integrated assembler
- SSE domain fixing code enabled for AVX (Bruno/Jakob).  Domain fixing pass is
-     now target independent (ExecutionDepsFix pass). (Jakob)
- X86 backend synthesizes horizontal add/sub instructions from generic code.
- returns_twice attribute (rafael)
- Tablegen has been split into a library, clang tblgen pieces now live in clang.
-   The llvm version is now named llvm-tblgen instead of tblgen.
- X86: Tons of encoding improvements and new instructions (e.g. Atom, Ivy Bridge,
-      and BMI instructions)
-     added to assembler and disassembler (Craig Topper)
- data layout string can encode the natural alignment of the target's stack for better optimization (LangRef.html#datalayout)
- -->
-  
-<ul>
-
-<!--
-<li></li>
--->
-  
-</ul>
-  
-</div>
+   -->
 
-<!--=========================================================================-->
-
-<!-- EH details: to be moved to a blog post:
- 
+<p>LLVM 3.0 includes several major changes:</p>
 
+<ul>
+<li>llvm-gcc is no longer supported, and not included in the release.  We 
+    recommend switching to <a
+       href="http://clang.llvm.org/">Clang</a> or <a 
+       href="http://dragonegg.llvm.org/">DragonEgg</a>.</li>
+
+<li>The linear scan register allocator has been replaced with a new "greedy"
+    register allocator, enabling live range splitting and many other
+    optimizations that lead to better code quality.  Please see its <a
+    href="http://blog.llvm.org/2011/09/greedy-register-allocation-in-llvm-30.html">blog post</a> or its talk at the <a 
+      href="http://llvm.org/devmtg/2011-11/">Developer Meeting</a>
+    for more information.</li>
+<li> New <a href="Atomics.html">atomics</a> instructions, "#i_fence" instruction, cmpxchg, atomicrmw too.  What target support (X86/ARM)? Also 'atomic load/store'. 
+</li>
+<li>The LLVM IR exception handling representation has been redesigned and
+    reimplemented, making it more elegant, fixing a huge number of bugs, and
+    enabling inlining and other optimizations.  Please see its blog post (XXX
+    not yet) for more information.</li>
+<li>The LLVM IR Type system has been redesigned and reimplemented, making it
+    faster and solving some long-standing problems.
+    Please see its <a 
+    href="http://blog.llvm.org/2011/11/llvm-30-type-system-rewrite.html">blog
+    post</a> for more information.</li>
   
+<li>The MIPS backend has made major leaps in this release, going from an
+    experimental target to being virtually production quality that supports a
+    wide variety of MIPS subtargets.  See the <a href="#MIPS">MIPS section</a>
+    below for more information.</li>
   
-<p>One of the biggest changes is that 3.0 has a new exception handling
-   system. The old system used LLVM intrinsics to convey the exception handling
-   information to the code generator. It worked in most cases, but not
-   all. Inlining was especially difficult to get right. Also, the intrinsics
-   could be moved away from the <code>invoke</code> instruction, making it hard
-   to recover that information.</p>
-
-<p>The new EH system makes exception handling a first-class member of the IR. It
-   adds two new instructions:</p>
-
-<ul>
-  <li><a href="LangRef.html#i_landingpad"><code>landingpad</code></a> &mdash;
-      this instruction defines a landing pad basic block. It contains all of the
-      information that's needed by the code generator. It's also required to be
-      the first non-PHI instruction in the landing pad. In addition, a landing
-      pad may be jumped to only by the unwind edge of an <code>invoke</code>
-      instruction.</li>
-
-  <li><a href="LangRef.html#i_resume"><code>resume</code></a> &mdash; this
-      instruction causes the current exception to resume traveling up the
-      stack. It replaces the <code>@llvm.eh.resume</code> intrinsic.</li>
+<li>The optimizer and code generator now supports gprof and gcov-style coverage
+    and profiling information, and includes a new llvm-cov tool.  Clang exposes
+    this through GCC-compatible command line options.</li>
 </ul>
 
-<p>Converting from the old EH API to the new EH API is rather simple, because a
-   lot of complexity has been removed. The two intrinsics,
-   <code>@llvm.eh.exception</code> and <code>@llvm.eh.selector</code> have been
-   superseded by the <code>landingpad</code> instruction. Instead of generating
-   a call to <code>@llvm.eh.exception</code> and <code>@llvm.eh.selector</code>:
-
-<div class="doc_code">
-<pre>
-Function *ExcIntr = Intrinsic::getDeclaration(TheModule,
-                                              Intrinsic::eh_exception);
-Function *SlctrIntr = Intrinsic::getDeclaration(TheModule,
-                                                Intrinsic::eh_selector);
-
-// The exception pointer.
-Value *ExnPtr = Builder.CreateCall(ExcIntr, "exc_ptr");
-
-std::vector&lt;Value*&gt; Args;
-Args.push_back(ExnPtr);
-Args.push_back(Builder.CreateBitCast(Personality,
-                                     Type::getInt8PtrTy(Context)));
-
-<i>// Add selector clauses to Args.</i>
-
-// The selector call.
-Builder.CreateCall(SlctrIntr, Args, "exc_sel");
-</pre>
-</div>
-
-<p>You should instead generate a <code>landingpad</code> instruction, that
-   returns an exception object and selector value:</p>
-
-<div class="doc_code">
-<pre>
-LandingPadInst *LPadInst =
-  Builder.CreateLandingPad(StructType::get(Int8PtrTy, Int32Ty, NULL),
-                           Personality, 0);
-
-Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
-Builder.CreateStore(LPadExn, getExceptionSlot());
-
-Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
-Builder.CreateStore(LPadSel, getEHSelectorSlot());
-</pre>
 </div>
 
-<p>It's now trivial to add the individual clauses to the <code>landingpad</code>
-   instruction.</p>
-
-<div class="doc_code">
-<pre>
-<i><b>// Adding a catch clause</b></i>
-Constant *TypeInfo = getTypeInfo();
-LPadInst-&gt;addClause(TypeInfo);
-
-<i><b>// Adding a C++ catch-all</b></i>
-LPadInst-&gt;addClause(Constant::getNullValue(Builder.getInt8PtrTy()));
-
-<i><b>// Adding a cleanup</b></i>
-LPadInst-&gt;setCleanup(true);
-
-<i><b>// Adding a filter clause</b></i>
-std::vector&lt;Constant*&gt; TypeInfos;
-Constant *TypeInfo = getFilterTypeInfo();
-TypeInfos.push_back(Builder.CreateBitCast(TypeInfo, Builder.getInt8PtrTy()));
-
-ArrayType *FilterTy = ArrayType::get(Int8PtrTy, TypeInfos.size());
-LPadInst-&gt;addClause(ConstantArray::get(FilterTy, TypeInfos));
-</pre>
-</div>
-
-<p>Converting from using the <code>@llvm.eh.resume</code> intrinsic to
-   the <code>resume</code> instruction is trivial. It takes the exception
-   pointer and exception selector values returned by
-   the <code>landingpad</code> instruction:</p>
-
-<div class="doc_code">
-<pre>
-Type *UnwindDataTy = StructType::get(Builder.getInt8PtrTy(),
-                                     Builder.getInt32Ty(), NULL);
-Value *UnwindData = UndefValue::get(UnwindDataTy);
-Value *ExcPtr = Builder.CreateLoad(getExceptionObjSlot());
-Value *ExcSel = Builder.CreateLoad(getExceptionSelSlot());
-UnwindData = Builder.CreateInsertValue(UnwindData, ExcPtr, 0, "exc_ptr");
-UnwindData = Builder.CreateInsertValue(UnwindData, ExcSel, 1, "exc_sel");
-Builder.CreateResume(UnwindData);
-</pre>
-</div>
-
-
- 
- 
- -->
   
 <!--=========================================================================-->
 <h3>
@@ -958,8 +802,15 @@ Builder.CreateResume(UnwindData);
 <p>LLVM IR has several new features for better support of new targets and that
    expose new optimization opportunities:</p>
 
-  
-  
+  New llvm.expect intrinsic.
+  New llvm.fma intrinsic.
+
+  LangRef.html#fnattrs uwtable attribute for asynch unwind tables.
+  llvm.prefetch now takes a 4th argument that specifies whether the prefetch happens to the icache or dcache.
+  New nonlazybind function attribute.
+  data layout string can encode the natural alignment of the target's stack for better optimization (LangRef.html#datalayout)
+  returns_twice attribute (rafael)
+
 </div>
 
 <!--=========================================================================-->
@@ -997,6 +848,8 @@ Builder.CreateResume(UnwindData);
    optimizers:</p>
 
 <ul>
+  Pass manager extension API.
+
 <li>Information about <a href="BranchWeightMetadata.html">branch probability</a>
     and basic block frequency is now available within LLVM, based on a
     combination of static branch prediction heuristics and
@@ -1004,7 +857,9 @@ Builder.CreateResume(UnwindData);
     register spill placement and if-conversion, with additional optimizations
     planned for future releases.  The same framework is intended for eventual
     use with profile-guided optimization.</li>
-</li>
+
+  ARC language specific optimizer (Transforms/ObjCARC) a decent example of language-specific transformation.
+
   
 </ul>
 
@@ -1038,6 +893,17 @@ compiler and provides better integration with the platform ABI as a result.</p>
    the <a href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro
    to the LLVM MC Project Blog Post</a>.</p>
 
+  
+  InstAliases now automatically used in the asmprinter where they are shorter.
+
+  Table generated MC expansion logic for pseudo instructions that expand to multiple MC instructions through the PseudoInstExpansion class. (JimG)
+  
+  #line directives in integrated assembler
+
+  llvm-rtdyld: JimG
+  llvm-objdump / dwarf parser library / llvm-dwarfdump (d0k)
+  object file parsing stuff and llvm-size (mspencer)
+
 </div>
 
 <!--=========================================================================-->
@@ -1052,6 +918,17 @@ compiler and provides better integration with the platform ABI as a result.</p>
    make it run faster:</p>
 
 <ul>
+  
+  better performance for indirect gotos through new tail dup pass.
+
+  Codegen now supports vector "select" operations on vector comparisons, turning
+  them into various optimized code sequences (e.g. using the SSE4/AVX "blend"
+  instructions).
+
+  EH and debug information produced with CFI directives, yielding smaller executables: http://blog.mozilla.com/respindola/2011/05/12/cfi-directives/
+
+  Domain fixing pass is now target independent (ExecutionDepsFix pass). (Jakob)
+
 <!--
 <li></li>
 -->
@@ -1081,6 +958,16 @@ compiler and provides better integration with the platform ABI as a result.</p>
       <code>@llvm.x86.sse42.crc32.32.[8|16|32]</code> and
       <code>@llvm.x86.sse42.crc32.64.[8|64]</code>.</li>
 
+  X86: inline assembler supports .code32 and .code64.
+  AVX support, assembler, compiler and disassembler.
+  X86 backend support for NaCl (David Meyer / Nick L)
+  SSE domain fixing code enabled for AVX (Bruno/Jakob).  
+  X86 backend synthesizes horizontal add/sub instructions from generic code.
+  X86: Tons of encoding improvements and new instructions (e.g. Atom, Ivy Bridge,
+  and BMI instructions)
+  added to assembler and disassembler (Craig Topper)
+  X86-64 generates smaller and faster code at -O0 (fast isel improvements)
+
 </ul>
 
 </div>
@@ -1098,6 +985,12 @@ compiler and provides better integration with the platform ABI as a result.</p>
   <li>Reworked Set Jump Long Jump EH Lowering,</li>
   <li>improved support for Cortex-M series processors, and</li>
   <li>beta quality integrated assembler support.</li>
+  
+  Better code generation for Cortex-A9
+  ARM inline asm constraints implemented.
+  Old arm disassembler replaced with a new one based on autogenerated encoding information from ARM .td files.
+  Better performance for Neon code in clang due to SRoA improvements.
+
 </ul>
 </div>
 
@@ -1181,6 +1074,15 @@ compiler and provides better integration with the platform ABI as a result.</p>
    from the previous release.</p>
 
 <ul>
+  <li>LLVM's configure script doesn't depend on llvm-gcc anymore, clean layering.</p>
+  LLVM 3.0 removes support for reading LLVM 2.8 and earlier files.  Aim to maintain compatibility all the way back to 3.0 "forever".
+  Frontend tests removed from llvm/test/Frontend* 
+  Tablegen has been split into a library, clang tblgen pieces now live in clang.
+  The llvm version is now named llvm-tblgen instead of tblgen.
+    PostOrder Dominator frontiers were removed.
+    LowerSetJmp pass removed, unused.
+
+
   <li>The <code>LLVMC</code> meta compiler driver was removed.</li>
   <li>The <code>LowerSetJmp</code> pass wasn't used effectively by any
       target and has been removed.</li>
@@ -1343,8 +1245,8 @@ compiler and provides better integration with the platform ABI as a result.</p>
   
 <ul>
   <li>The Alpha, Blackfin, CellSPU, MSP430, PTX, SystemZ and
-      XCore backends are experimental, and several of these have already been
-      removed from mainline.</li>
+      XCore backends are experimental, and the Alpha, Blackfin and SystemZ
+      targets have already been removed from mainline.</li>
 
   <li>The integrated assembler, disassembler, and JIT is not supported by
       several targets.  If an integrated assembler is not supported, then a
@@ -1381,6 +1283,130 @@ compiler and provides better integration with the platform ABI as a result.</p>
 
 </div>
 
+<!--=========================================================================-->
+
+<!-- EH details: to be moved to a blog post:
+ 
+
+  
+  
+<p>One of the biggest changes is that 3.0 has a new exception handling
+   system. The old system used LLVM intrinsics to convey the exception handling
+   information to the code generator. It worked in most cases, but not
+   all. Inlining was especially difficult to get right. Also, the intrinsics
+   could be moved away from the <code>invoke</code> instruction, making it hard
+   to recover that information.</p>
+
+<p>The new EH system makes exception handling a first-class member of the IR. It
+   adds two new instructions:</p>
+
+<ul>
+  <li><a href="LangRef.html#i_landingpad"><code>landingpad</code></a> &mdash;
+      this instruction defines a landing pad basic block. It contains all of the
+      information that's needed by the code generator. It's also required to be
+      the first non-PHI instruction in the landing pad. In addition, a landing
+      pad may be jumped to only by the unwind edge of an <code>invoke</code>
+      instruction.</li>
+
+  <li><a href="LangRef.html#i_resume"><code>resume</code></a> &mdash; this
+      instruction causes the current exception to resume traveling up the
+      stack. It replaces the <code>@llvm.eh.resume</code> intrinsic.</li>
+</ul>
+
+<p>Converting from the old EH API to the new EH API is rather simple, because a
+   lot of complexity has been removed. The two intrinsics,
+   <code>@llvm.eh.exception</code> and <code>@llvm.eh.selector</code> have been
+   superseded by the <code>landingpad</code> instruction. Instead of generating
+   a call to <code>@llvm.eh.exception</code> and <code>@llvm.eh.selector</code>:
+
+<div class="doc_code">
+<pre>
+Function *ExcIntr = Intrinsic::getDeclaration(TheModule,
+                                              Intrinsic::eh_exception);
+Function *SlctrIntr = Intrinsic::getDeclaration(TheModule,
+                                                Intrinsic::eh_selector);
+
+// The exception pointer.
+Value *ExnPtr = Builder.CreateCall(ExcIntr, "exc_ptr");
+
+std::vector&lt;Value*&gt; Args;
+Args.push_back(ExnPtr);
+Args.push_back(Builder.CreateBitCast(Personality,
+                                     Type::getInt8PtrTy(Context)));
+
+<i>// Add selector clauses to Args.</i>
+
+// The selector call.
+Builder.CreateCall(SlctrIntr, Args, "exc_sel");
+</pre>
+</div>
+
+<p>You should instead generate a <code>landingpad</code> instruction, that
+   returns an exception object and selector value:</p>
+
+<div class="doc_code">
+<pre>
+LandingPadInst *LPadInst =
+  Builder.CreateLandingPad(StructType::get(Int8PtrTy, Int32Ty, NULL),
+                           Personality, 0);
+
+Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
+Builder.CreateStore(LPadExn, getExceptionSlot());
+
+Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
+Builder.CreateStore(LPadSel, getEHSelectorSlot());
+</pre>
+</div>
+
+<p>It's now trivial to add the individual clauses to the <code>landingpad</code>
+   instruction.</p>
+
+<div class="doc_code">
+<pre>
+<i><b>// Adding a catch clause</b></i>
+Constant *TypeInfo = getTypeInfo();
+LPadInst-&gt;addClause(TypeInfo);
+
+<i><b>// Adding a C++ catch-all</b></i>
+LPadInst-&gt;addClause(Constant::getNullValue(Builder.getInt8PtrTy()));
+
+<i><b>// Adding a cleanup</b></i>
+LPadInst-&gt;setCleanup(true);
+
+<i><b>// Adding a filter clause</b></i>
+std::vector&lt;Constant*&gt; TypeInfos;
+Constant *TypeInfo = getFilterTypeInfo();
+TypeInfos.push_back(Builder.CreateBitCast(TypeInfo, Builder.getInt8PtrTy()));
+
+ArrayType *FilterTy = ArrayType::get(Int8PtrTy, TypeInfos.size());
+LPadInst-&gt;addClause(ConstantArray::get(FilterTy, TypeInfos));
+</pre>
+</div>
+
+<p>Converting from using the <code>@llvm.eh.resume</code> intrinsic to
+   the <code>resume</code> instruction is trivial. It takes the exception
+   pointer and exception selector values returned by
+   the <code>landingpad</code> instruction:</p>
+
+<div class="doc_code">
+<pre>
+Type *UnwindDataTy = StructType::get(Builder.getInt8PtrTy(),
+                                     Builder.getInt32Ty(), NULL);
+Value *UnwindData = UndefValue::get(UnwindDataTy);
+Value *ExcPtr = Builder.CreateLoad(getExceptionObjSlot());
+Value *ExcSel = Builder.CreateLoad(getExceptionSelSlot());
+UnwindData = Builder.CreateInsertValue(UnwindData, ExcPtr, 0, "exc_ptr");
+UnwindData = Builder.CreateInsertValue(UnwindData, ExcSel, 1, "exc_sel");
+Builder.CreateResume(UnwindData);
+</pre>
+</div>
+
+
+ 
+ 
+ -->
+
+  
 <!-- *********************************************************************** -->
 
 <hr>
-- 
2.34.1