[C++11] Add range based accessors for the Use-Def chain of a Value.

This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
   detail
2) Change it to actually be a *Use* iterator rather than a *User*
   iterator.
3) Add an adaptor which is a User iterator that always looks through the
   Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
   they wanted a use_iterator (and to explicitly dig out the User when
   needed), or a user_iterator which makes the Use itself totally
   opaque.

Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.

The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.

However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203364 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth
2014-03-09 03:16:01 +00:00
parent b033b03c23
commit 36b699f2b1
100 changed files with 920 additions and 1075 deletions

View File

@ -332,7 +332,7 @@ void BitcodeReaderValueList::ResolveConstantForwardRefs() {
// new value. If they reference more than one placeholder, update them all
// at once.
while (!Placeholder->use_empty()) {
Value::use_iterator UI = Placeholder->use_begin();
auto UI = Placeholder->user_begin();
User *U = *UI;
// If the using object isn't uniqued, just update the operands. This
@ -3116,8 +3116,8 @@ error_code BitcodeReader::Materialize(GlobalValue *GV) {
for (UpgradedIntrinsicMap::iterator I = UpgradedIntrinsics.begin(),
E = UpgradedIntrinsics.end(); I != E; ++I) {
if (I->first != I->second) {
for (Value::use_iterator UI = I->first->use_begin(),
UE = I->first->use_end(); UI != UE; ) {
for (auto UI = I->first->user_begin(), UE = I->first->user_end();
UI != UE;) {
if (CallInst* CI = dyn_cast<CallInst>(*UI++))
UpgradeIntrinsicCall(CI, I->second);
}
@ -3172,8 +3172,8 @@ error_code BitcodeReader::MaterializeModule(Module *M) {
for (std::vector<std::pair<Function*, Function*> >::iterator I =
UpgradedIntrinsics.begin(), E = UpgradedIntrinsics.end(); I != E; ++I) {
if (I->first != I->second) {
for (Value::use_iterator UI = I->first->use_begin(),
UE = I->first->use_end(); UI != UE; ) {
for (auto UI = I->first->user_begin(), UE = I->first->user_end();
UI != UE;) {
if (CallInst* CI = dyn_cast<CallInst>(*UI++))
UpgradeIntrinsicCall(CI, I->second);
}