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DIEHash: Refactor ref attribute hashing into smaller functions

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193360 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Blaikie 2013-10-24 17:51:43 +00:00
parent 724452e94c
commit 851aa948cb
3 changed files with 98 additions and 68 deletions
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1
lib/CodeGen/AsmPrinter/DIE.h
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@ -138,6 +138,7 @@ namespace llvm {
// Accessors.
DIEAbbrev &getAbbrev() { return Abbrev; }
const DIEAbbrev &getAbbrev() const { return Abbrev; }
unsigned getAbbrevNumber() const { return Abbrev.getNumber(); }
dwarf::Tag getTag() const { return Abbrev.getTag(); }
unsigned getOffset() const { return Offset; }

152
lib/CodeGen/AsmPrinter/DIEHash.cpp
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@ -28,9 +28,9 @@ using namespace llvm;
/// \brief Grabs the string in whichever attribute is passed in and returns
/// a reference to it.
static StringRef getDIEStringAttr(DIE *Die, uint16_t Attr) {
const SmallVectorImpl<DIEValue *> &Values = Die->getValues();
const DIEAbbrev &Abbrevs = Die->getAbbrev();
static StringRef getDIEStringAttr(const DIE &Die, uint16_t Attr) {
const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
const DIEAbbrev &Abbrevs = Die.getAbbrev();
// Iterate through all the attributes until we find the one we're
// looking for, if we can't find it return an empty string.
@ -109,7 +109,7 @@ void DIEHash::addParentContext(DIE *Parent) {
addULEB128(Die->getTag());
// ... Then the name, taken from the DW_AT_name attribute.
StringRef Name = getDIEStringAttr(Die, dwarf::DW_AT_name);
StringRef Name = getDIEStringAttr(*Die, dwarf::DW_AT_name);
DEBUG(dbgs() << "... adding context: " << Name << "\n");
if (!Name.empty())
addString(Name);
@ -187,6 +187,84 @@ void DIEHash::collectAttributes(DIE *Die, DIEAttrs &Attrs) {
}
}
void DIEHash::hashShallowTypeReference(dwarf::Attribute Attribute,
const DIE &Entry, StringRef Name) {
// append the letter 'N'
addULEB128('N');
// the DWARF attribute code (DW_AT_type or DW_AT_friend),
addULEB128(Attribute);
// the context of the tag,
if (DIE *Parent = Entry.getParent())
addParentContext(Parent);
// the letter 'E',
addULEB128('E');
// and the name of the type.
addString(Name);
// Currently DW_TAG_friends are not used by Clang, but if they do become so,
// here's the relevant spec text to implement:
//
// For DW_TAG_friend, if the referenced entry is the DW_TAG_subprogram,
// the context is omitted and the name to be used is the ABI-specific name
// of the subprogram (e.g., the mangled linker name).
}
void DIEHash::hashRepeatedTypeReference(dwarf::Attribute Attribute,
unsigned DieNumber) {
// a) If T is in the list of [previously hashed types], use the letter
// 'R' as the marker
addULEB128('R');
addULEB128(Attribute);
// and use the unsigned LEB128 encoding of [the index of T in the
// list] as the attribute value;
addULEB128(DieNumber);
}
void DIEHash::hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
DIE &Entry) {
assert(Tag != dwarf::DW_TAG_friend && "No current LLVM clients emit friend "
"tags. Add support here when there's "
"a use case");
// Step 5
// If the tag in Step 3 is one of [the below tags]
if ((Tag == dwarf::DW_TAG_pointer_type ||
Tag == dwarf::DW_TAG_reference_type ||
Tag == dwarf::DW_TAG_rvalue_reference_type ||
Tag == dwarf::DW_TAG_ptr_to_member_type) &&
// and the referenced type (via the [below attributes])
// FIXME: This seems overly restrictive, and causes hash mismatches
// there's a decl/def difference in the containing type of a
// ptr_to_member_type, but it's what DWARF says, for some reason.
Attribute == dwarf::DW_AT_type) {
// [FIXME] ... has a DW_AT_name attribute,
hashShallowTypeReference(Attribute, Entry,
getDIEStringAttr(Entry, dwarf::DW_AT_name));
return;
}
unsigned &DieNumber = Numbering[&Entry];
if (DieNumber) {
hashRepeatedTypeReference(Attribute, DieNumber);
return;
}
// otherwise, b) use the letter 'T' as a the marker, ...
addULEB128('T');
addULEB128(Attribute);
// ... process the type T recursively by performing Steps 2 through 7, and
// use the result as the attribute value.
DieNumber = Numbering.size();
computeHash(&Entry);
}
// Hash an individual attribute \param Attr based on the type of attribute and
// the form.
void DIEHash::hashAttribute(AttrEntry Attr, dwarf::Tag Tag) {
@ -198,69 +276,7 @@ void DIEHash::hashAttribute(AttrEntry Attr, dwarf::Tag Tag) {
// ... An attribute that refers to another type entry T is processed as
// follows:
if (const DIEEntry *EntryAttr = dyn_cast<DIEEntry>(Value)) {
DIE *Entry = EntryAttr->getEntry();
assert(Tag != dwarf::DW_TAG_friend && "No current LLVM clients emit friend "
"tags. Add support here when there's "
"a use case");
// Step 5
// If the tag in Step 3 is one of [the below tags]
if ((Tag == dwarf::DW_TAG_pointer_type ||
Tag == dwarf::DW_TAG_reference_type ||
Tag == dwarf::DW_TAG_rvalue_reference_type ||
Tag == dwarf::DW_TAG_ptr_to_member_type) &&
// and the referenced type (via the [below attributes])
// FIXME: This seems overly restrictive, and causes hash mismatches
// there's a decl/def difference in the containing type of a
// ptr_to_member_type.
Attribute == dwarf::DW_AT_type) {
// [FIXME] ... has a DW_AT_name attribute,
// append the letter 'N'
addULEB128('N');
// the DWARF attribute code (DW_AT_type or DW_AT_friend),
addULEB128(Desc->getAttribute());
// the context of the tag,
if (DIE *Parent = Entry->getParent())
addParentContext(Parent);
// the letter 'E',
addULEB128('E');
// and the name of the type.
addString(getDIEStringAttr(Entry, dwarf::DW_AT_name));
// FIXME:
// For DW_TAG_friend, if the referenced entry is the DW_TAG_subprogram,
// the context is omitted and the name to be used is the ABI-specific name
// of the subprogram (e.g., the mangled linker name).
return;
}
unsigned &DieNumber = Numbering[Entry];
if (DieNumber) {
// a) If T is in the list of [previously hashed types], use the letter
// 'R' as the marker
addULEB128('R');
addULEB128(Attribute);
// and use the unsigned LEB128 encoding of [the index of T in the
// list] as the attribute value;
addULEB128(DieNumber);
return;
}
// otherwise, b) use the letter 'T' as a the marker, ...
addULEB128('T');
addULEB128(Attribute);
// ... process the type T recursively by performing Steps 2 through 7, and
// use the result as the attribute value.
DieNumber = Numbering.size();
computeHash(Entry);
hashDIEEntry(Attribute, Tag, *EntryAttr->getEntry());
return;
}
@ -407,7 +423,7 @@ uint64_t DIEHash::computeDIEODRSignature(DIE *Die) {
addULEB128(Die->getTag());
// Add the name of the type to the hash.
addString(getDIEStringAttr(Die, dwarf::DW_AT_name));
addString(getDIEStringAttr(*Die, dwarf::DW_AT_name));
// Now get the result.
MD5::MD5Result Result;

13
lib/CodeGen/AsmPrinter/DIEHash.h
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@ -124,6 +124,19 @@ private:
/// \brief Hashes an individual attribute.
void hashAttribute(AttrEntry Attr, dwarf::Tag Tag);
/// \brief Hashes an attribute that refers to another DIE.
void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
DIE &Entry);
/// \brief Hashes a reference to a named type in such a way that is
/// independent of whether that type is described by a declaration or a
/// definition.
void hashShallowTypeReference(dwarf::Attribute Attribute,
const DIE &Entry, StringRef Name);
/// \brief Hashes a reference to a previously referenced type DIE.
void hashRepeatedTypeReference(dwarf::Attribute Attribute, unsigned DieNumber);
private:
MD5 Hash;
DenseMap<DIE*, unsigned> Numbering;