6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-11-01 15:17:25 +00:00
Code Issues Projects Releases Wiki Activity

Add scoped-noalias metadata

Browse Source 
This commit adds scoped noalias metadata. The primary motivations for this
feature are:
  1. To preserve noalias function attribute information when inlining
  2. To provide the ability to model block-scope C99 restrict pointers

Neither of these two abilities are added here, only the necessary
infrastructure. In fact, there should be no change to existing functionality,
only the addition of new features. The logic that converts noalias function
parameters into this metadata during inlining will come in a follow-up commit.

What is added here is the ability to generally specify noalias memory-access
sets. Regarding the metadata, alias-analysis scopes are defined similar to TBAA
nodes:

!scope0 = metadata !{ metadata !"scope of foo()" }
!scope1 = metadata !{ metadata !"scope 1", metadata !scope0 }
!scope2 = metadata !{ metadata !"scope 2", metadata !scope0 }
!scope3 = metadata !{ metadata !"scope 2.1", metadata !scope2 }
!scope4 = metadata !{ metadata !"scope 2.2", metadata !scope2 }

Loads and stores can be tagged with an alias-analysis scope, and also, with a
noalias tag for a specific scope:

... = load %ptr1, !alias.scope !{ !scope1 }
... = load %ptr2, !alias.scope !{ !scope1, !scope2 }, !noalias !{ !scope1 }

When evaluating an aliasing query, if one of the instructions is associated
with an alias.scope id that is identical to the noalias scope associated with
the other instruction, or is a descendant (in the scope hierarchy) of the
noalias scope associated with the other instruction, then the two memory
accesses are assumed not to alias.

Note that is the first element of the scope metadata is a string, then it can
be combined accross functions and translation units. The string can be replaced
by a self-reference to create globally unqiue scope identifiers.

[Note: This overview is slightly stylized, since the metadata nodes really need
to just be numbers (!0 instead of !scope0), and the scope lists are also global
unnamed metadata.]

Existing noalias metadata in a callee is "cloned" for use by the inlined code.
This is necessary because the aliasing scopes are unique to each call site
(because of possible control dependencies on the aliasing properties). For
example, consider a function: foo(noalias a, noalias b) { *a = *b; } that gets
inlined into bar() { ... if (...) foo(a1, b1); ... if (...) foo(a2, b2); } --
now just because we know that a1 does not alias with b1 at the first call site,
and a2 does not alias with b2 at the second call site, we cannot let inlining
these functons have the metadata imply that a1 does not alias with b2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213864 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel
2014-07-24 14:25:39 +00:00
parent e8d5c379ac
commit 16fd27b2c3
31 changed files with 834 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
include/llvm/IR/IRBuilder.h
View File

@@ -364,43 +364,60 @@ public:
/// \brief Create and insert a memset to the specified pointer and the
/// specified value.
///
/// If the pointer isn't an i8*, it will be converted. If a TBAA tag is
/// specified, it will be added to the instruction.
/// If the pointer isn't an i8*, it will be converted. If a TBAA tag is
/// specified, it will be added to the instruction. Likewise with alias.scope
/// and noalias tags.
CallInst *CreateMemSet(Value *Ptr, Value *Val, uint64_t Size, unsigned Align,
bool isVolatile = false, MDNode *TBAATag = nullptr) {
return CreateMemSet(Ptr, Val, getInt64(Size), Align, isVolatile, TBAATag);
bool isVolatile = false, MDNode *TBAATag = nullptr,
MDNode *ScopeTag = nullptr,
MDNode *NoAliasTag = nullptr) {
return CreateMemSet(Ptr, Val, getInt64(Size), Align, isVolatile,
TBAATag, ScopeTag, NoAliasTag);
}
CallInst *CreateMemSet(Value *Ptr, Value *Val, Value *Size, unsigned Align,
bool isVolatile = false, MDNode *TBAATag = nullptr);
bool isVolatile = false, MDNode *TBAATag = nullptr,
MDNode *ScopeTag = nullptr,
MDNode *NoAliasTag = nullptr);
/// \brief Create and insert a memcpy between the specified pointers.
///
/// If the pointers aren't i8*, they will be converted. If a TBAA tag is
/// specified, it will be added to the instruction.
/// specified, it will be added to the instruction. Likewise with alias.scope
/// and noalias tags.
CallInst *CreateMemCpy(Value *Dst, Value *Src, uint64_t Size, unsigned Align,
bool isVolatile = false, MDNode *TBAATag = nullptr,
MDNode *TBAAStructTag = nullptr) {
MDNode *TBAAStructTag = nullptr,
MDNode *ScopeTag = nullptr,
MDNode *NoAliasTag = nullptr) {
return CreateMemCpy(Dst, Src, getInt64(Size), Align, isVolatile, TBAATag,
TBAAStructTag);
TBAAStructTag, ScopeTag, NoAliasTag);
}
CallInst *CreateMemCpy(Value *Dst, Value *Src, Value *Size, unsigned Align,
bool isVolatile = false, MDNode *TBAATag = nullptr,
MDNode *TBAAStructTag = nullptr);
MDNode *TBAAStructTag = nullptr,
MDNode *ScopeTag = nullptr,
MDNode *NoAliasTag = nullptr);
/// \brief Create and insert a memmove between the specified
/// pointers.
///
/// If the pointers aren't i8*, they will be converted. If a TBAA tag is
/// specified, it will be added to the instruction.
/// specified, it will be added to the instruction. Likewise with alias.scope
/// and noalias tags.
CallInst *CreateMemMove(Value *Dst, Value *Src, uint64_t Size, unsigned Align,
bool isVolatile = false, MDNode *TBAATag = nullptr) {
return CreateMemMove(Dst, Src, getInt64(Size), Align, isVolatile, TBAATag);
bool isVolatile = false, MDNode *TBAATag = nullptr,
MDNode *ScopeTag = nullptr,
MDNode *NoAliasTag = nullptr) {
return CreateMemMove(Dst, Src, getInt64(Size), Align, isVolatile,
TBAATag, ScopeTag, NoAliasTag);
}
CallInst *CreateMemMove(Value *Dst, Value *Src, Value *Size, unsigned Align,
bool isVolatile = false, MDNode *TBAATag = nullptr);
bool isVolatile = false, MDNode *TBAATag = nullptr,
MDNode *ScopeTag = nullptr,
MDNode *NoAliasTag = nullptr);
/// \brief Create a lifetime.start intrinsic.
///

4
include/llvm/IR/LLVMContext.h
View File

@@ -52,7 +52,9 @@ public:
MD_fpmath = 3, // "fpmath"
MD_range = 4, // "range"
MD_tbaa_struct = 5, // "tbaa.struct"
MD_invariant_load = 6 // "invariant.load"
MD_invariant_load = 6, // "invariant.load"
MD_alias_scope = 7, // "alias.scope"
MD_noalias = 8 // "noalias"
};
/// getMDKindID - Return a unique non-zero ID for the specified metadata kind.

31
include/llvm/IR/MDBuilder.h
View File

@@ -63,24 +63,49 @@ public:
MDNode *createRange(const APInt &Lo, const APInt &Hi);
//===------------------------------------------------------------------===//
// TBAA metadata.
// AA metadata.
//===------------------------------------------------------------------===//
/// \brief Return metadata appropriate for a TBAA root node. Each returned
protected:
/// \brief Return metadata appropriate for a AA root node (scope or TBAA).
/// Each returned node is distinct from all other metadata and will never
/// be identified (uniqued) with anything else.
MDNode *createAnonymousAARoot(StringRef Name = StringRef());
public:
/// \brief Return metadata appropriate for a TBAA root node. Each returned
/// node is distinct from all other metadata and will never be identified
/// (uniqued) with anything else.
MDNode *createAnonymousTBAARoot();
MDNode *createAnonymousTBAARoot() {
return createAnonymousAARoot();
}
/// \brief Return metadata appropriate for an alias scope root node.
/// Each returned node is distinct from all other metadata and will never
/// be identified (uniqued) with anything else.
MDNode *createAnonymousAliasScopeRoot(StringRef Name = StringRef()) {
return createAnonymousAARoot(Name);
}
/// \brief Return metadata appropriate for a TBAA root node with the given
/// name. This may be identified (uniqued) with other roots with the same
/// name.
MDNode *createTBAARoot(StringRef Name);
/// \brief Return metadata appropriate for an alias scope root node with
/// the given name. This may be identified (uniqued) with other roots with
/// the same name.
MDNode *createAliasScopeRoot(StringRef Name);
/// \brief Return metadata for a non-root TBAA node with the given name,
/// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
MDNode *createTBAANode(StringRef Name, MDNode *Parent,
bool isConstant = false);
/// \brief Return metadata for a non-root alias scope node with the given
/// name and parent in the scope tree.
MDNode *createAliasScopeNode(StringRef Name, MDNode *Parent);
struct TBAAStructField {
uint64_t Offset;
uint64_t Size;

24
include/llvm/IR/Metadata.h
View File

@@ -70,8 +70,8 @@ public:
/// AAMDNodes - A collection of metadata nodes that might be associated with a
/// memory access used by the alias-analysis infrastructure.
struct AAMDNodes {
AAMDNodes(MDNode *T = nullptr)
: TBAA(T) {}
AAMDNodes(MDNode *T = nullptr, MDNode *S = nullptr, MDNode *N = nullptr)
: TBAA(T), Scope(S), NoAlias(N) {}
bool operator == (const AAMDNodes &A) const {
return equals(A);
@@ -82,15 +82,21 @@ struct AAMDNodes {
}
operator bool() const {
return TBAA;
return TBAA || Scope || NoAlias;
}
/// TBAA - The tag for type-based alias analysis.
MDNode *TBAA;
/// Scope - The tag for alias scope specification (used with noalias).
MDNode *Scope;
/// NoAlias - The tag specifying the noalias scope.
MDNode *NoAlias;
protected:
bool equals(const AAMDNodes &A) const {
return TBAA == A.TBAA;
return TBAA == A.TBAA && Scope == A.Scope && NoAlias == A.NoAlias;
}
};
@@ -98,13 +104,15 @@ protected:
template<>
struct DenseMapInfo<AAMDNodes> {
static inline AAMDNodes getEmptyKey() {
return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey());
return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(), 0, 0);
}
static inline AAMDNodes getTombstoneKey() {
return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey());
return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(), 0, 0);
}
static unsigned getHashValue(const AAMDNodes &Val) {
return DenseMapInfo<MDNode *>::getHashValue(Val.TBAA);
return DenseMapInfo<MDNode *>::getHashValue(Val.TBAA) ^
DenseMapInfo<MDNode *>::getHashValue(Val.Scope) ^
DenseMapInfo<MDNode *>::getHashValue(Val.NoAlias);
}
static bool isEqual(const AAMDNodes &LHS, const AAMDNodes &RHS) {
return LHS == RHS;
@@ -214,6 +222,8 @@ public:
bool isTBAAVtableAccess() const;
/// Methods for metadata merging.
static MDNode *concatenate(MDNode *A, MDNode *B);
static MDNode *intersect(MDNode *A, MDNode *B);
static MDNode *getMostGenericTBAA(MDNode *A, MDNode *B);
static AAMDNodes getMostGenericAA(const AAMDNodes &A, const AAMDNodes &B);
static MDNode *getMostGenericFPMath(MDNode *A, MDNode *B);