the noalias argument on function attributes be usable to model the
C99 restrict keyword on arguments, and to allow AliasAnalysis to
consider a noalias-attributed argument to be an "identified object".
To support this, refactor a new "based on" concept out of the current
pointer aliasing "associated" concept. This "based on" concept is very
similar to (though it is not identical with) the "based on" concept
in C99.
Also, reword the definition of NoAlias to more closely describe the
concept that the optimizer uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107495 91177308-0d34-0410-b5e6-96231b3b80d8
Objective-C metadata types which should be marked as "weak", but which the
linker will remove upon final linkage. However, this linkage isn't specific to
Objective-C.
For example, the "objc_msgSend_fixup_alloc" symbol is defined like this:
.globl l_objc_msgSend_fixup_alloc
.weak_definition l_objc_msgSend_fixup_alloc
.section __DATA, __objc_msgrefs, coalesced
.align 3
l_objc_msgSend_fixup_alloc:
.quad _objc_msgSend_fixup
.quad L_OBJC_METH_VAR_NAME_1
This is different from the "linker_private" linkage type, because it can't have
the metadata defined with ".weak_definition".
Currently only supported on Darwin platforms.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107433 91177308-0d34-0410-b5e6-96231b3b80d8
metadata types which should be marked as "weak", but which the linker will
remove upon final linkage. For example, the "objc_msgSend_fixup_alloc" symbol is
defined like this:
.globl l_objc_msgSend_fixup_alloc
.weak_definition l_objc_msgSend_fixup_alloc
.section __DATA, __objc_msgrefs, coalesced
.align 3
l_objc_msgSend_fixup_alloc:
.quad _objc_msgSend_fixup
.quad L_OBJC_METH_VAR_NAME_1
This is different from the "linker_private" linkage type, because it can't have
the metadata defined with ".weak_definition".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107205 91177308-0d34-0410-b5e6-96231b3b80d8
NOTE: 2nd part changeset for cfe trunk to follow.
*** PRE-PATCH ISSUES ADDRESSED
- clang api docs fail build from objdir
- clang/llvm api docs collide in install PREFIX/
- clang/llvm main docs collide in install
- clang/llvm main docs have full of hard coded destination
assumptions and make use of absolute root in static html files;
namely CommandGuide tools hard codes a website destination
for cross references and some html cross references assume
website root paths
*** IMPROVEMENTS
- bumped Doxygen from 1.4.x -> 1.6.3
- splits llvm/clang docs into 'main' and 'api' (doxygen) build trees
- provide consistent, reliable doc builds for both main+api docs
- support buid vs. install vs. website intentions
- support objdir builds
- document targets with 'make help'
- correct clean and uninstall operations
- use recursive dir delete only where absolutely necessary
- added call function fn.RMRF which safeguards against botched 'rm -rf';
if any target (or any variable is evaluated) which attempts
to remove any dirs which match a hard-coded 'safelist', a verbose
error will be printed and make will error-stop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103213 91177308-0d34-0410-b5e6-96231b3b80d8
terminator instructions so that it applies to all terminators with
multiple successors, including invoke.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102909 91177308-0d34-0410-b5e6-96231b3b80d8
of dependence and define trap values in terms of dependence, instead
of trying to cover the concept with a flurry of ad-hoc rules.
The dependence model isn't complete yet, but it's already much more
rigorous than the description it replaces.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102479 91177308-0d34-0410-b5e6-96231b3b80d8
traps flowing through memory references, add some text to
better cover phi nodes and externally-visible side effects,
add an example of instructions being control-dependent
on a trap value, and reword some of the existing trap rules.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102399 91177308-0d34-0410-b5e6-96231b3b80d8
the definition of the nsw and nuw flags to make use of it.
nsw was introduced to help optimizers answer yes to the following:
// Can we change i from i32 to i64 to eliminate the cast inside the loop?
for (int i = 0; i < n; ++i) A[i] *= 0.1;
// Can we assume that this loop will eventually terminate?
for (int i = 0; i <= n; ++i) A[i] *= 0.1;
In its current form, it isn't truly sufficient for either.
In the first case, if the increment overflows, it'll still have some
valid i32 value; sign-extending it will produce a value which is 33
homogeneous sign bits trailed by 31 independent undef bits. If i is
promoted to i64, it won't have those same values when it reaches that
point. (The compiler could recover here by reasoning about how i is
used by the load, but that's a lot more complicated and isn't always
possible.)
In the second case, there is no value for i which will be greater than
n, so having the increment return undef on overflow doesn't help.
Trap values are a formalization of some existing concepts that we have
about LLVM IR, and give the optimizers a better basis for answering yes
to both questions above.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102140 91177308-0d34-0410-b5e6-96231b3b80d8
Have the asmprinter use the mdnode to scavenge a source location if
present. Document this nonsense in langref.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100607 91177308-0d34-0410-b5e6-96231b3b80d8
