patch brings numerous advantages to LLVM. One way to look at it
is through diffstat:
109 files changed, 3005 insertions(+), 5906 deletions(-)
Removing almost 3K lines of code is a good thing. Other advantages
include:
1. Value::getType() is a simple load that can be CSE'd, not a mutating
union-find operation.
2. Types a uniqued and never move once created, defining away PATypeHolder.
3. Structs can be "named" now, and their name is part of the identity that
uniques them. This means that the compiler doesn't merge them structurally
which makes the IR much less confusing.
4. Now that there is no way to get a cycle in a type graph without a named
struct type, "upreferences" go away.
5. Type refinement is completely gone, which should make LTO much MUCH faster
in some common cases with C++ code.
6. Types are now generally immutable, so we can use "Type *" instead
"const Type *" everywhere.
Downsides of this patch are that it removes some functions from the C API,
so people using those will have to upgrade to (not yet added) new API.
"LLVM 3.0" is the right time to do this.
There are still some cleanups pending after this, this patch is large enough
as-is.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134829 91177308-0d34-0410-b5e6-96231b3b80d8
and clean recursive descent parser.
This change has a couple of ramifications:
1. The parser code is about 400 lines shorter (in what we maintain, not
including what is autogenerated).
2. The code should be significantly faster than the old code because we
don't have to work around bison's poor handling of datatypes with
ctors/dtors. This also makes the code much more resistant to memory
leaks.
3. We now get caret diagnostics from the .ll parser, woo.
4. The actual diagnostics emited from the parser are completely different
so a bunch of testcases had to be updated.
5. I now disallow "%ty = type opaque %ty = type i32". There was no good
reason to support this, it was just an accident of the old
implementation. I have no reason to think that anyone is actually using
this.
6. The syntax for sticking a global variable has changed to make it
unambiguous. I don't think anyone is depending on this since only clang
supports this and it is not solid yet, so I'm not worried about anything
breaking.
7. This gets rid of the last use of bison, and along with it the .cvs files.
I'll prune this from the makefiles as a subsequent commit.
There are a few minor cleanups that can be done after this commit (suggestions
welcome!) but this passes dejagnu testing and is ready for its time in the
limelight.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61558 91177308-0d34-0410-b5e6-96231b3b80d8
