commit c2ec0725cedceb851858c3991fbdd36ee9ac85dd
author Nick Lewycky <nicholas@mxc.ca> Sat Jul 06 00:29:58 2013 +0000
committer Nick Lewycky <nicholas@mxc.ca> Sat Jul 06 00:29:58 2013 +0000
tree 841ddf4ab15a0d446543803d7124a7716619cb04
parent e8545dde7be8fe78e64bf4d9578c25368243c274

Extend 'readonly' and 'readnone' to work on function arguments as well as
functions. Make the function attributes pass add it to known library functions
and when it can deduce it.

llvm-svn: 185735

llvm/lib/IR/Attributes.cpp

diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index 2160ea2..59da815 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -1157,6 +1157,8 @@
       .addAttribute(Attribute::Nest)
       .addAttribute(Attribute::NoAlias)
       .addAttribute(Attribute::NoCapture)
+      .addAttribute(Attribute::ReadNone)
+      .addAttribute(Attribute::ReadOnly)
       .addAttribute(Attribute::StructRet);
 
   return AttributeSet::get(Ty->getContext(), Index, Incompatible);

llvm/lib/IR/Function.cpp

diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 7f7efabf..bf9d949 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -131,6 +131,15 @@
     hasAttribute(getArgNo()+1, Attribute::Returned);
 }
 
+/// Return true if this argument has the readonly or readnone attribute on it
+/// in its containing function.
+bool Argument::onlyReadsMemory() const {
+  return getParent()->getAttributes().
+      hasAttribute(getArgNo()+1, Attribute::ReadOnly) ||
+      getParent()->getAttributes().
+      hasAttribute(getArgNo()+1, Attribute::ReadNone);
+}
+
 /// addAttr - Add attributes to an argument.
 void Argument::addAttr(AttributeSet AS) {
   assert(AS.getNumSlots() <= 1 &&
@@ -711,4 +720,3 @@
 
   return false;
 }
-

llvm/lib/IR/Verifier.cpp

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 8b4c165..420bc15 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -654,7 +654,7 @@
 }
 
 void Verifier::VerifyAttributeTypes(AttributeSet Attrs, unsigned Idx,
-                                    bool isFunction, const Value* V) {
+                                    bool isFunction, const Value *V) {
   unsigned Slot = ~0U;
   for (unsigned I = 0, E = Attrs.getNumSlots(); I != E; ++I)
     if (Attrs.getSlotIndex(I) == Idx) {
@@ -671,8 +671,6 @@
 
     if (I->getKindAsEnum() == Attribute::NoReturn ||
         I->getKindAsEnum() == Attribute::NoUnwind ||
-        I->getKindAsEnum() == Attribute::ReadNone ||
-        I->getKindAsEnum() == Attribute::ReadOnly ||
         I->getKindAsEnum() == Attribute::NoInline ||
         I->getKindAsEnum() == Attribute::AlwaysInline ||
         I->getKindAsEnum() == Attribute::OptimizeForSize ||
@@ -696,14 +694,21 @@
         I->getKindAsEnum() == Attribute::NoBuiltin ||
         I->getKindAsEnum() == Attribute::Cold) {
       if (!isFunction) {
-          CheckFailed("Attribute '" + I->getAsString() +
-                      "' only applies to functions!", V);
-          return;
+        CheckFailed("Attribute '" + I->getAsString() +
+                    "' only applies to functions!", V);
+        return;
+      }
+    } else if (I->getKindAsEnum() == Attribute::ReadOnly ||
+               I->getKindAsEnum() == Attribute::ReadNone) {
+      if (Idx == 0) {
+        CheckFailed("Attribute '" + I->getAsString() +
+                    "' does not apply to function returns");
+        return;
       }
     } else if (isFunction) {
-        CheckFailed("Attribute '" + I->getAsString() +
-                    "' does not apply to functions!", V);
-        return;
+      CheckFailed("Attribute '" + I->getAsString() +
+                  "' does not apply to functions!", V);
+      return;
     }
   }
 }