[IR/AsmWriter] Output escape sequences if the first character isdigit()

If the first character in a metadata attachment's name is a digit, it has
to be output using an escape sequence, otherwise it's not valid text IR.

Removed an over-zealous assert from LLVMContext which didn't allow this.
The rule should only apply to text IR. Actual names can have any sequence
of non-NUL bytes.

Also added some documentation on accepted names.

Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238867 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Filipe Cabecinhas 2015-06-02 21:25:08 +00:00
parent 66774f6700
commit 6af0f89f37
4 changed files with 23 additions and 9 deletions

View File

@ -834,6 +834,11 @@ Named metadata is a collection of metadata. :ref:`Metadata
nodes <metadata>` (but not metadata strings) are the only valid
operands for a named metadata.
#. Named metadata are represented as a string of characters with the
metadata prefix. The rules for metadata names are the same as for
identifiers, but quoted names are not allowed. ``"\xx"`` type escapes
are still valid, which allows any character to be part of a name.
Syntax::
; Some unnamed metadata nodes, which are referenced by the named metadata.

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@ -2215,9 +2215,8 @@ void AssemblyWriter::printModule(const Module *M) {
}
}
void AssemblyWriter::printNamedMDNode(const NamedMDNode *NMD) {
Out << '!';
StringRef Name = NMD->getName();
static void printMetadataIdentifier(StringRef Name,
formatted_raw_ostream &Out) {
if (Name.empty()) {
Out << "<empty name> ";
} else {
@ -2235,6 +2234,11 @@ void AssemblyWriter::printNamedMDNode(const NamedMDNode *NMD) {
Out << '\\' << hexdigit(C >> 4) << hexdigit(C & 0x0F);
}
}
}
void AssemblyWriter::printNamedMDNode(const NamedMDNode *NMD) {
Out << '!';
printMetadataIdentifier(NMD->getName(), Out);
Out << " = !{";
for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
if (i)
@ -3006,9 +3010,10 @@ void AssemblyWriter::printMetadataAttachments(
for (const auto &I : MDs) {
unsigned Kind = I.first;
Out << Separator;
if (Kind < MDNames.size())
Out << "!" << MDNames[Kind];
else
if (Kind < MDNames.size()) {
Out << "!";
printMetadataIdentifier(MDNames[Kind], Out);
} else
Out << "!<unknown kind #" << Kind << ">";
Out << ' ';
WriteAsOperandInternal(Out, I.second, &TypePrinter, &Machine, TheModule);

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@ -242,9 +242,6 @@ void LLVMContext::emitError(unsigned LocCookie, const Twine &ErrorStr) {
/// Return a unique non-zero ID for the specified metadata kind.
unsigned LLVMContext::getMDKindID(StringRef Name) const {
assert(!std::isdigit(Name.front()) &&
"Named metadata may not start with a digit");
// If this is new, assign it its ID.
return pImpl->CustomMDKindNames.insert(
std::make_pair(

View File

@ -22,6 +22,13 @@ define void @test3() !bar !3 {
unreachable, !bar !4
}
; CHECK-LABEL: define void @test_attachment_name() {
; CHECK: unreachable, !\342abc !4
define void @test_attachment_name() {
;; Escape the first character when printing text IR, since it's a digit
unreachable, !\34\32abc !4
}
!0 = !DILocation(line: 662302, column: 26, scope: !1)
!1 = !DISubprogram(name: "foo")
!2 = distinct !{}