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author | Tom Stellard <thomas.stellard@amd.com> | 2015-11-11 21:45:36 +0000 |
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committer | Tom Stellard <thomas.stellard@amd.com> | 2015-11-11 21:45:36 +0000 |
commit | 2f5098ca7d2d90b2baae76f7447fb16e55aeb4fd (patch) | |
tree | f523455ae57d34643b7d891094529a6c0d06f1dc | |
parent | 7f42f9d4d7895f8ffc546ac4bbcc8d9a61bc9288 (diff) |
Merging r246882:
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r246882 | hfinkel | 2015-09-04 17:49:21 -0400 (Fri, 04 Sep 2015) | 32 lines
Don't crash on a self-alias declaration
We were crashing in CodeGen given input like this:
int self_alias(void) __attribute__((weak, alias("self_alias")));
such a self-alias is invalid, but instead of diagnosing the situation, we'd
proceed to produce IR for both the function declaration and the alias. Because
we already had a function named 'self_alias', the alias could not be named the
same thing, and so LLVM would pick a different name ('self_alias1' for example)
for that value. When we later called CodeGenModule::checkAliases, we'd look up
the IR value corresponding to the alias name, find the function declaration
instead, and then assert in a cast to llvm::GlobalAlias. The easiest way to prevent
this is simply to avoid creating the wrongly-named alias value in the first
place and issue the diagnostic there (instead of in checkAliases). We detect a
related cycle case in CodeGenModule::EmitAliasDefinition already, so this just
adds a second such check.
Even though the other test cases for this 'alias definition is part of a cycle'
diagnostic are in test/Sema/attr-alias-elf.c, I've added a separate regression
test for this case. This is because I can't add this check to
test/Sema/attr-alias-elf.c without disturbing the other test cases in that
file. In order to avoid construction of the bad IR values, this diagnostic
is emitted from within CodeGenModule::EmitAliasDefinition (and the relevant
declaration is not added to the Aliases vector). The other cycle checks are
done within the CodeGenModule::checkAliases function based on the Aliases
vector, called from CodeGenModule::Release. However, if there have been errors
earlier, HandleTranslationUnit does not call Release, and so checkAliases is
never called, and so none of the other diagnostics would be produced.
Fixes PR23509.
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_37@252808 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | lib/CodeGen/CodeGenModule.cpp | 5 | ||||
-rw-r--r-- | test/Sema/attr-self-alias.c | 4 |
2 files changed, 9 insertions, 0 deletions
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp index a179ad42ea..c9c48c7628 100644 --- a/lib/CodeGen/CodeGenModule.cpp +++ b/lib/CodeGen/CodeGenModule.cpp @@ -2493,6 +2493,11 @@ void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { StringRef MangledName = getMangledName(GD); + if (AA->getAliasee() == MangledName) { + Diags.Report(AA->getLocation(), diag::err_cyclic_alias); + return; + } + // If there is a definition in the module, then it wins over the alias. // This is dubious, but allow it to be safe. Just ignore the alias. llvm::GlobalValue *Entry = GetGlobalValue(MangledName); diff --git a/test/Sema/attr-self-alias.c b/test/Sema/attr-self-alias.c new file mode 100644 index 0000000000..7c50458be3 --- /dev/null +++ b/test/Sema/attr-self-alias.c @@ -0,0 +1,4 @@ +// RUN: %clang_cc1 -triple x86_64-pc-linux -fsyntax-only -verify -emit-llvm-only %s + +int self_alias(void) __attribute__((weak, alias("self_alias"))); // expected-error {{alias definition is part of a cycle}} + |