[llvm] r180019 - Clarify that llvm.used can contain aliases.
Daniel Dunbar
daniel at zuster.org
Wed Apr 24 09:33:22 PDT 2013
Hi Rafael,
This change causes a Clang crash when using LTO and building the test-suite
tools, which completely breaks testing with LTO. Can you take a look?
--
$ cd ~/llvm-test-suite/tools
$ clang-r180193-t20130424_085843-b4726/bin/clang -v
clang version 3.3 (trunk 180193)
Target: x86_64-apple-darwin10.7.0
Thread model: posix
$ env DYLD_LIBRARY_PATH=$(pwd)/clang-r180193-t20130424_085843-b4726/lib
clang-r180193-t20130424_085843-b4726/bin/clang -flto -Os timeit.c Assertion
failed: (isa<X>(Val) && "cast<Ty>() argument of incompatible type!"),
function cast, file
/Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/build.clang-x86_64-darwin10-RA/llvm/include/llvm/Support/Casting.h,
line 237.
Stack dump:
0. Running pass 'Merge Duplicate Global Constants' on module 'ld-temp.o'.
clang: error: unable to execute command: Illegal instruction
clang: error: linker command failed due to signal (use -v to see invocation)
--
- Daniel
On Mon, Apr 22, 2013 at 7:58 AM, Rafael Espindola <
rafael.espindola at gmail.com> wrote:
> Author: rafael
> Date: Mon Apr 22 09:58:02 2013
> New Revision: 180019
>
> URL: http://llvm.org/viewvc/llvm-project?rev=180019&view=rev
> Log:
> Clarify that llvm.used can contain aliases.
>
> Also add a check for llvm.used in the verifier and simplify clients now
> that
> they can assume they have a ConstantArray.
>
> Added:
> llvm/trunk/test/Verifier/llvm.used-invalid-init.ll
> llvm/trunk/test/Verifier/llvm.used-invalid-init2.ll
> llvm/trunk/test/Verifier/llvm.used-invalid-type.ll
> llvm/trunk/test/Verifier/llvm.used-invalid-type2.ll
> llvm/trunk/test/Verifier/llvm.used-ptr-type.ll
> Modified:
> llvm/trunk/docs/LangRef.rst
> llvm/trunk/include/llvm/CodeGen/AsmPrinter.h
> llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
> llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp
> llvm/trunk/lib/IR/Verifier.cpp
> llvm/trunk/lib/Transforms/IPO/ConstantMerge.cpp
> llvm/trunk/lib/Transforms/IPO/StripSymbols.cpp
> llvm/trunk/lib/Transforms/Scalar/GlobalMerge.cpp
> llvm/trunk/test/Feature/aliases.ll
>
> Modified: llvm/trunk/docs/LangRef.rst
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/docs/LangRef.rst (original)
> +++ llvm/trunk/docs/LangRef.rst Mon Apr 22 09:58:02 2013
> @@ -2868,9 +2868,9 @@ All globals of this sort should have a s
> The '``llvm.used``' Global Variable
> -----------------------------------
>
> -The ``@llvm.used`` global is an array with i8\* element type which has
> -:ref:`appending linkage <linkage_appending>`. This array contains a list
> of
> -pointers to global variables and functions which may optionally have a
> +The ``@llvm.used`` global is an array which has
> + :ref:`appending linkage <linkage_appending>`. This array contains a list
> of
> +pointers to global variables, functions and aliases which may optionally
> have a
> pointer cast formed of bitcast or getelementptr. For example, a legal
> use of it is:
>
> @@ -2884,13 +2884,13 @@ use of it is:
> i8* bitcast (i32* @Y to i8*)
> ], section "llvm.metadata"
>
> -If a global variable appears in the ``@llvm.used`` list, then the
> -compiler, assembler, and linker are required to treat the symbol as if
> -there is a reference to the global that it cannot see. For example, if a
> -variable has internal linkage and no references other than that from the
> -``@llvm.used`` list, it cannot be deleted. This is commonly used to
> -represent references from inline asms and other things the compiler
> -cannot "see", and corresponds to "``attribute((used))``" in GNU C.
> +If a symbol appears in the ``@llvm.used`` list, then the compiler,
> assembler,
> +and linker are required to treat the symbol as if there is a reference to
> the
> +symbol that it cannot see. For example, if a variable has internal
> linkage and
> +no references other than that from the ``@llvm.used`` list, it cannot be
> +deleted. This is commonly used to represent references from inline asms
> and
> +other things the compiler cannot "see", and corresponds to
> +"``attribute((used))``" in GNU C.
>
> On some targets, the code generator must emit a directive to the
> assembler or object file to prevent the assembler and linker from
>
> Modified: llvm/trunk/include/llvm/CodeGen/AsmPrinter.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/AsmPrinter.h?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/CodeGen/AsmPrinter.h (original)
> +++ llvm/trunk/include/llvm/CodeGen/AsmPrinter.h Mon Apr 22 09:58:02 2013
> @@ -25,6 +25,7 @@ namespace llvm {
> class BlockAddress;
> class GCStrategy;
> class Constant;
> + class ConstantArray;
> class GCMetadataPrinter;
> class GlobalValue;
> class GlobalVariable;
> @@ -480,7 +481,7 @@ namespace llvm {
> void EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
> const MachineBasicBlock *MBB,
> unsigned uid) const;
> - void EmitLLVMUsedList(const Constant *List);
> + void EmitLLVMUsedList(const ConstantArray *InitList);
> void EmitXXStructorList(const Constant *List, bool isCtor);
> GCMetadataPrinter *GetOrCreateGCPrinter(GCStrategy *C);
> };
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp Mon Apr 22 09:58:02
> 2013
> @@ -1213,7 +1213,7 @@ void AsmPrinter::EmitJumpTableEntry(cons
> bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
> if (GV->getName() == "llvm.used") {
> if (MAI->hasNoDeadStrip()) // No need to emit this at all.
> - EmitLLVMUsedList(GV->getInitializer());
> + EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
> return true;
> }
>
> @@ -1256,11 +1256,8 @@ bool AsmPrinter::EmitSpecialLLVMGlobal(c
> /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark
> each
> /// global in the specified llvm.used list for which emitUsedDirectiveFor
> /// is true, as being used with this directive.
> -void AsmPrinter::EmitLLVMUsedList(const Constant *List) {
> +void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
> // Should be an array of 'i8*'.
> - const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
> - if (InitList == 0) return;
> -
> for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
> const GlobalValue *GV =
> dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
>
> Modified: llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp (original)
> +++ llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp Mon Apr 22 09:58:02 2013
> @@ -326,8 +326,7 @@ void MachineModuleInfo::AnalyzeModule(co
> if (!GV || !GV->hasInitializer()) return;
>
> // Should be an array of 'i8*'.
> - const ConstantArray *InitList =
> dyn_cast<ConstantArray>(GV->getInitializer());
> - if (InitList == 0) return;
> + const ConstantArray *InitList =
> cast<ConstantArray>(GV->getInitializer());
>
> for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
> if (const Function *F =
>
> Modified: llvm/trunk/lib/IR/Verifier.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Verifier.cpp?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/IR/Verifier.cpp (original)
> +++ llvm/trunk/lib/IR/Verifier.cpp Mon Apr 22 09:58:02 2013
> @@ -449,6 +449,29 @@ void Verifier::visitGlobalVariable(Globa
> }
> }
>
> + if (GV.hasName() && (GV.getName() == "llvm.used")) {
> + Assert1(!GV.hasInitializer() || GV.hasAppendingLinkage(),
> + "invalid linkage for intrinsic global variable", &GV);
> + Type *GVType = GV.getType()->getElementType();
> + if (ArrayType *ATy = dyn_cast<ArrayType>(GVType)) {
> + PointerType *PTy = dyn_cast<PointerType>(ATy->getElementType());
> + Assert1(PTy, "wrong type for intrinsic global variable", &GV);
> + if (GV.hasInitializer()) {
> + Constant *Init = GV.getInitializer();
> + ConstantArray *InitArray = dyn_cast<ConstantArray>(Init);
> + Assert1(InitArray, "wrong initalizer for intrinsic global
> variable",
> + Init);
> + for (unsigned i = 0, e = InitArray->getNumOperands(); i != e;
> ++i) {
> + Value *V = Init->getOperand(i)->stripPointerCasts();
> + // stripPointerCasts strips aliases, so we only need to check
> for
> + // variables and functions.
> + Assert1(isa<GlobalVariable>(V) || isa<Function>(V),
> + "invalid llvm.used member", V);
> + }
> + }
> + }
> + }
> +
> visitGlobalValue(GV);
> }
>
>
> Modified: llvm/trunk/lib/Transforms/IPO/ConstantMerge.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/ConstantMerge.cpp?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Transforms/IPO/ConstantMerge.cpp (original)
> +++ llvm/trunk/lib/Transforms/IPO/ConstantMerge.cpp Mon Apr 22 09:58:02
> 2013
> @@ -66,9 +66,8 @@ ModulePass *llvm::createConstantMergePas
> static void FindUsedValues(GlobalVariable *LLVMUsed,
> SmallPtrSet<const GlobalValue*, 8>
> &UsedValues) {
> if (LLVMUsed == 0) return;
> - ConstantArray *Inits =
> dyn_cast<ConstantArray>(LLVMUsed->getInitializer());
> - if (Inits == 0) return;
> -
> + ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
> +
> for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
> if (GlobalValue *GV =
> dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
>
> Modified: llvm/trunk/lib/Transforms/IPO/StripSymbols.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/StripSymbols.cpp?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Transforms/IPO/StripSymbols.cpp (original)
> +++ llvm/trunk/lib/Transforms/IPO/StripSymbols.cpp Mon Apr 22 09:58:02 2013
> @@ -195,10 +195,9 @@ static void findUsedValues(GlobalVariabl
> SmallPtrSet<const GlobalValue*, 8>
> &UsedValues) {
> if (LLVMUsed == 0) return;
> UsedValues.insert(LLVMUsed);
> -
> - ConstantArray *Inits =
> dyn_cast<ConstantArray>(LLVMUsed->getInitializer());
> - if (Inits == 0) return;
> -
> +
> + ConstantArray *Inits = cast<ConstantArray>(LLVMUsed->getInitializer());
> +
> for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
> if (GlobalValue *GV =
>
> dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
>
> Modified: llvm/trunk/lib/Transforms/Scalar/GlobalMerge.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GlobalMerge.cpp?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Scalar/GlobalMerge.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/GlobalMerge.cpp Mon Apr 22 09:58:02
> 2013
> @@ -200,9 +200,8 @@ void GlobalMerge::collectUsedGlobalVaria
> if (!GV || !GV->hasInitializer()) return;
>
> // Should be an array of 'i8*'.
> - const ConstantArray *InitList =
> dyn_cast<ConstantArray>(GV->getInitializer());
> - if (InitList == 0) return;
> -
> + const ConstantArray *InitList =
> cast<ConstantArray>(GV->getInitializer());
> +
> for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
> if (const GlobalVariable *G =
>
> dyn_cast<GlobalVariable>(InitList->getOperand(i)->stripPointerCasts()))
>
> Modified: llvm/trunk/test/Feature/aliases.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Feature/aliases.ll?rev=180019&r1=180018&r2=180019&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/Feature/aliases.ll (original)
> +++ llvm/trunk/test/Feature/aliases.ll Mon Apr 22 09:58:02 2013
> @@ -2,6 +2,8 @@
> ; RUN: llvm-as %t1.ll -o - | llvm-dis > %t2.ll
> ; RUN: diff %t1.ll %t2.ll
>
> + at llvm.used = appending global [1 x i8*] [i8* bitcast (i32* @foo1 to
> i8*)], section "llvm.metadata"
> +
> @bar = external global i32
> @foo1 = alias i32* @bar
> @foo2 = alias i32* @bar
>
> Added: llvm/trunk/test/Verifier/llvm.used-invalid-init.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Verifier/llvm.used-invalid-init.ll?rev=180019&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Verifier/llvm.used-invalid-init.ll (added)
> +++ llvm/trunk/test/Verifier/llvm.used-invalid-init.ll Mon Apr 22 09:58:02
> 2013
> @@ -0,0 +1,6 @@
> +; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
> +
> + at llvm.used = appending global [1 x i8*] zeroinitializer, section
> "llvm.metadata"
> +
> +; CHECK: wrong initalizer for intrinsic global variable
> +; CHECK-NEXT: [1 x i8*] zeroinitializer
>
> Added: llvm/trunk/test/Verifier/llvm.used-invalid-init2.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Verifier/llvm.used-invalid-init2.ll?rev=180019&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Verifier/llvm.used-invalid-init2.ll (added)
> +++ llvm/trunk/test/Verifier/llvm.used-invalid-init2.ll Mon Apr 22
> 09:58:02 2013
> @@ -0,0 +1,7 @@
> +; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
> +
> + at a = global i8 42
> + at llvm.used = appending global [2 x i8*] [i8* @a, i8* null], section
> "llvm.metadata"
> +
> +; CHECK: invalid llvm.used member
> +; CHECK-NEXT: i8* null
>
> Added: llvm/trunk/test/Verifier/llvm.used-invalid-type.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Verifier/llvm.used-invalid-type.ll?rev=180019&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Verifier/llvm.used-invalid-type.ll (added)
> +++ llvm/trunk/test/Verifier/llvm.used-invalid-type.ll Mon Apr 22 09:58:02
> 2013
> @@ -0,0 +1,6 @@
> +; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
> +
> + at llvm.used = appending global [1 x i32] [i32 0], section "llvm.metadata"
> +
> +; CHECK: wrong type for intrinsic global variable
> +; CHECK-NEXT: [1 x i32]* @llvm.used
>
> Added: llvm/trunk/test/Verifier/llvm.used-invalid-type2.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Verifier/llvm.used-invalid-type2.ll?rev=180019&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Verifier/llvm.used-invalid-type2.ll (added)
> +++ llvm/trunk/test/Verifier/llvm.used-invalid-type2.ll Mon Apr 22
> 09:58:02 2013
> @@ -0,0 +1,5 @@
> +; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
> + at llvm.used = appending global i32 0, section "llvm.metadata"
> +
> +; CHECK: Only global arrays can have appending linkage!
> +; CHEKC-NEXT: i32* @llvm.used
>
> Added: llvm/trunk/test/Verifier/llvm.used-ptr-type.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Verifier/llvm.used-ptr-type.ll?rev=180019&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Verifier/llvm.used-ptr-type.ll (added)
> +++ llvm/trunk/test/Verifier/llvm.used-ptr-type.ll Mon Apr 22 09:58:02 2013
> @@ -0,0 +1,4 @@
> +; RUN: llvm-as < %s -o /dev/null
> +
> + at a = global i32 42
> + at llvm.used = appending global [1 x i32*] [i32* @a], section
> "llvm.metadata"
>
>
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