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author | Tanya Lattner <tonic@nondot.org> | 2007-05-16 23:25:46 +0000 |
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committer | Tanya Lattner <tonic@nondot.org> | 2007-05-16 23:25:46 +0000 |
commit | b6ec3a933d13fbfd4fe3d8944ae58770affec2f1 (patch) | |
tree | e565c35bf653f77b87a09a40df8b2892e655867f /docs/ReleaseNotes.html | |
parent | 98a6c62aff7393683571b05f73f6f22701569c09 (diff) | |
download | external_llvm-b6ec3a933d13fbfd4fe3d8944ae58770affec2f1.zip external_llvm-b6ec3a933d13fbfd4fe3d8944ae58770affec2f1.tar.gz external_llvm-b6ec3a933d13fbfd4fe3d8944ae58770affec2f1.tar.bz2 |
Merged in both release announcement guts.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37131 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs/ReleaseNotes.html')
-rw-r--r-- | docs/ReleaseNotes.html | 253 |
1 files changed, 241 insertions, 12 deletions
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index df23d29..179e23a 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -96,8 +96,58 @@ release series, like we did within the 1.x series.</li> </p> <ul> -<li>ding dong llvm-gcc3 is dead</li> -<li>bytecode -> bitcode</li> + +<li>llvm-gcc3 is now officially unsupported. Users are required to + upgrade to llvm-gcc4. llvm-gcc4 includes many features over + llvm-gcc3, is faster, and is much easier to build.</li> + +<li>Integer types are now completely signless. This means that we + have types like i8/i16/i32 instead of ubyte/sbyte/short/ushort/int + etc. LLVM operations that depend on sign have been split up into + separate instructions (<a href="http://llvm.org/PR950">PR950</a>).</li> + +<li>Arbitrary bitwidth integers (e.g. i13, i36, i42, etc) are now + supported in the LLVM IR and optimizations. However, neither llvm-gcc nor + the native code generators support non-standard width integers + (<a href="http://llvm.org/PR1043">PR1043</a>).</li> + +<li>'type planes' have been removed (<a href="http://llvm.org/PR411">PR411</a>). + It is no longer possible to have two values with the same name in the + same symbol table. This simplifies LLVM internals, allowing significant + speedups.</li> + +<li>Global variables and functions in .ll files are now prefixed with + @ instead of % (<a href="http://llvm.org/PR645">PR645</a>).</li> + +<li>The LLVM 1.x "bytecode" format has been replaced with a + completely new binary representation, named 'bitcode'. Because we + plan to maintain binary compatibility between LLVM 2.x ".bc" files, + this is an important change to get right. Bitcode brings a number of + advantages to the LLVM over the old bytecode format. It is denser + (files are smaller), more extensible, requires less memory to read, + is easier to keep backwards compatible (so LLVM 2.5 will read 2.0 .bc + files), and has many other nice features.</li> + +<li>Support was added for alignment values on load and store + instructions (<a href="http://www.llvm.org/PR400">PR400</a>). This + allows the IR to express loads that are not + sufficiently aligned (e.g. due to pragma packed) or to capture extra + alignment information. </li> + +<li>LLVM now has a new MSIL backend. llc - march=msil will now turn LLVM + into MSIL (".net") bytecode. This is still fairly early development + with a number of limitations.</li> + +<li>Support has been added for 'protected visibility' in ELF.</li> + +<li>Thread Local Storage with the __thread keyword was implemented along + with added codegen support for Linux on X86 and ARM.</li> + +<li>ELF symbol aliases supported has been added.</li> + +<li>Added support for 'polymorphic intrinsics', allowing things like + llvm.ctpop to work on arbitrary width integers.</li> + </ul> </div> @@ -111,8 +161,30 @@ Improvements</a></div> </p> <ul> -<li>many new supported things</li> -<li>easier to configure on linux</li> +<li>Precompiled Headers (PCH) support has been implemented.</li> + +<li>Support for external weak linkage and hidden visibility has been added.</li> + +<li>Packed structure types are now supported , which allows LLVM to express + unaligned data more naturally.</li> + +<li>Inline assembly support has been improved and many bugs were fixed. + The two large missing features are support for 80-bit floating point stack + registers on X86 (<a href="http://llvm.org/PR879">PR879</a>), and support for inline asm in the C backend (<a href="http://llvm.org/PR802">PR802</a>).</li> + +<li>Ada support, such as nested functions, has been improved.</li> + +<li>Tracking function parameter/result attributes is now possible.</li> + +<li>Its is now easier to configure llvm-gcc for linux.</li> + +<li>Many enhancements have been added, such as improvements to NON_LVALUE_EXPR, + arrays with non-zero base, structs with variable sized fields, + VIEW_CONVERT_EXPR, CEIL_DIV_EXPR, and many other things.</li> + +<li>Improved "attribute packed" support in the CFE, and handle many + other obscure struct layout cases correctly.</li> + </ul> </div> @@ -125,7 +197,29 @@ Improvements</a></div> </p> <ul> -<li></li> +<li>The pass manager has been entirely rewritten, making it significantly + smaller, simpler, and more extensible. Support has been added to run + FunctionPasses interlaced with CallGraphSCCPasses.</li> + +<li>The -scalarrepl pass can now promote unions containing FP values into + a register, it can also handle unions of vectors of the same size.</li> + +<li>The predicate simplifier pass has been improved, making it able to do + simple value range propagation and eliminate more conditionals.</li> + +<li>There is a new new LoopPass class. The passmanager has been + modified to support it, and all existing loop xforms have been + converted to use it. </li> + +<li>There is a new loop rotation pass, which converts "for loops" into + "do/while loops", where the condition is at the bottom of the loop.</li> + +<li>ModulePasses may now use the result of FunctionPasses.</li> + +<li>The [Post]DominatorSet classes have been removed from LLVM and clients switched to use the far-more-efficient ETForest class instead. </li> + +<li>The ImmediateDominator class has also been removed, and clients have been switched to use DominatorTree instead.</li> + </ul> </div> @@ -140,14 +234,64 @@ New features include: </p> <ul> -<li></li> +<li>Support for Zero-cost DWARF exception handling has been added. It is mostly + complete and just in need of continued bug fixes and optimizations at + this point.</li> + +<li>Progress has been made on a direct Mach-o .o file writer. Many small + apps work, but it is not quite complete yet.</li> + +<li>Support was added for software floating point routines.</li> + +<li>DWARF debug information generation has been improved. LLVM now passes + most of the GDB testsuite on MacOS and debug info is more dense.</li> + +<li>A new register scavenger has been implemented, which is useful for + finding free registers after register allocation. This is useful when + rewriting frame references on RISC targets, for example.</li> + +<li>Heuristics have been added to avoid coalescing vregs with very large live + ranges to physregs.</li> + +<li>Support now exists for very simple (but still very useful) + rematerialization the register allocator, enough to move + instructions like "load immediate" and constant pool loads.</li> + +<li>Significantly improved 'switch' lowering, improving codegen for + sparse switches that have dense subregions, and implemented support + for the shift/and trick.</li> + +<li>The code generator now has more accurate and general hooks for + describing addressing modes ("isLegalAddressingMode") to + optimizations like loop strength reduction and code sinking.</li> + +<li>The Loop Strength Reduction pass has been improved, and support added + for sinking expressions across blocks to reduce register pressure.</li> + +<li>Added support for tracking physreg sub-registers and super-registers + in the code generator, as well as extensive register + allocator changes to track them.</li> + +<li>There is initial support for virtreg sub-registers + (<a href="http://llvm.org/PR1350">PR1350</a>).</li> + </ul> <p>In addition, the LLVM target description format has itself been extended in several ways:</p> <ul> -<li></li> +<li>Extended TargetData to support better target parameterization in + the .ll/.bc files, eliminating the 'pointersize/endianness' attributes + in the files (<a href="http://llvm.org/PR761">PR761</a>).</li> + +<li>TargetData was generalized for finer grained alignment handling, + handling of vector alignment, and handling of preferred alignment</li> + +<li>LLVM now supports describing target calling conventions + explicitly in .td files, reducing the amount of C++ code that needs + to be written for a port.</li> + </ul> <p>Further, several significant target-specific enhancements are included in @@ -165,25 +309,110 @@ Improvements</a></div> <div class="doc_text"> -<p>New features include: +<p>X86-Specific Code Generator Enhancements: </p> <ul> -<li></li> +<li>The scheduler was improved to better reduce register pressure on + X86 and other targets that are register pressure sensitive</li> +<li>Linux/x86-64 support has been improved.</li> +<li>PIC support for linux/x86 has been added.</li> +<li>Support now exists for the GCC regparm attribute, and code in the X86 + backend to respect it.</li> +<li>Various improvements have been made for the X86-64 JIT, allowing it to + generate code in the large code model</li> +<li>LLVM now supports inline asm with multiple constraint letters per operand + (like "ri") which is common in X86 inline asms.</li> +<li>Early support has been added for X86 inline asm in the C backend.</li> +<li>Added support for the X86 MMX instruction set.</li> + </ul> - + +<p>ARM-Specific Code Generator Enhancements: +</p> + +<ul> +<li>Several improvements have been made to the ARM backend, including basic + inline asm support, weak linkage support, static ctor/dtor support and + many bug fixes.</li> +<li>There are major enhancements to the ARM backend, including support for ARM + v4-v6, vfp support, soft float, pre/postinc support, load/store multiple + generation, constant pool entry motion (to support large functions), + and enhancements to ARM constant island pass. + </li> +<li>Added support for Thumb code generation (an ARM subtarget).</li> +<li>More aggressive size analysis for ARM inline asm strings was + implemented.</li> +</ul> + +</div> + +<p>Other Target-Specific Code Generator Enhancements: +</p> + +<ul> +<li>The PowerPC 64 JIT now supports addressing code loaded above the 2G + boundary.</li> + +<li>Improved support for the Linux/ppc ABI and the linux/ppc JIT is fully + functional now. llvm-gcc and static compilation are not fully supported + yet though.<</li> + +<li>Many bugs fixed for PowerPC 64.</li> + +<li>Support was added for the ARM AAPCS and EABI ABIs and PIC codegen on + arm/linux.</li> + +<li>Several bugs in DWARF debug emission on linux and cygwin/mingw were fixed. + Debugging basically works on these targets now.</li> + +<li>Support has been added for the X86-64 large code model to the JIT, + which is useful if JIT'd function bodies are more than 2G away from + library functions.</li> + +<li>Several bugs were fixed for DWARF debug info generation on arm/linux.</li> + +</ul> + </div> <!--_________________________________________________________________________--> <div class="doc_subsubsection"><a name="other">Other Improvements</a></div> <div class="doc_text"> -<p></p> + +<p>This release includes many other improvements, including +performance work, specifically designed to tune datastructure +usage. This makes several critical components faster.</p> <p>More specific changes include:</p> <ul> -<li></li> +<li>ConstantBool, ConstantIntegral and ConstantInt classes have been merged + together, we now just have ConstantInt</li> + +<li>LLVM no longer relies on static destructors to shut itself down. Instead, + it lazily initializes itself and shuts down when llvm_shutdown() is + explicitly called.</li> + +<li>LLVM now has significantly fewer static constructors, reducing startup time. + </li> + +<li>Several classes have been refactored to reduce the amount of code that + gets linked into apps that use the JIT.</li> + +<li>Construction of intrinsic function declarations has been simplified.</li> + +<li>The llvm-upgrade tool now exists. This migrates LLVM 1.9 .ll files to + LLVM 2.0 syntax.</li> + +<li>The gccas/gccld tools have been removed.</li> + +<li>Support has been added to llvm-test for running on low-memory + or slow machines (make SMALL_PROBLEM_SIZE=1).</li> + +<li>llvm-test is now more portable and should build with MS Visual Studio.</li> + </ul> </div> |