From 23ecb8f9e59b9853fb5abfb91b44af80eda76b8b Mon Sep 17 00:00:00 2001 From: Mitch Phillips Date: Wed, 6 Mar 2019 19:17:18 +0000 Subject: [PATCH] Revert "[IR][ARM] Add function pointer alignment to datalayout" This reverts commit 2391bfca97290181ae65796ea6da135d1b6d037b. This reverts rL355522 (https://reviews.llvm.org/D57335). Kills buildbots that use '-Werror' with the following error: /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm/lib/IR/Value.cpp:657:7: error: default label in switch which covers all enumeration values [-Werror,-Wcovered-switch-default] See buildbots http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/30200/steps/check-llvm%20asan/logs/stdio for more information. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355537 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/LangRef.rst | 8 --- include/llvm/IR/DataLayout.h | 23 ------- lib/IR/ConstantFold.cpp | 28 ++------ lib/IR/DataLayout.cpp | 20 ------ lib/IR/Value.cpp | 14 ++-- lib/Target/ARM/ARMTargetMachine.cpp | 4 -- unittests/IR/CMakeLists.txt | 1 - unittests/IR/ConstantsTest.cpp | 100 ---------------------------- unittests/IR/DataLayoutTest.cpp | 47 ------------- unittests/IR/FunctionTest.cpp | 25 ------- 10 files changed, 8 insertions(+), 262 deletions(-) delete mode 100644 unittests/IR/DataLayoutTest.cpp diff --git a/docs/LangRef.rst b/docs/LangRef.rst index 261d1d47d20..86972acf6ad 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -2004,14 +2004,6 @@ as follows: targets. ``a::`` This specifies the alignment for an object of aggregate type. -``F`` - This specifies the alignment for function pointers. - The options for ```` are: - - * ``i``: The alignment of function pointers is independent of the alignment - of functions, and is a multiple of ````. - * ``n``: The alignment of function pointers is a multiple of the explicit - alignment specified on the function, and is a multiple of ````. ``m:`` If present, specifies that llvm names are mangled in the output. Symbols prefixed with the mangling escape character ``\01`` are passed through diff --git a/include/llvm/IR/DataLayout.h b/include/llvm/IR/DataLayout.h index 05c72f10d30..869b27b1fda 100644 --- a/include/llvm/IR/DataLayout.h +++ b/include/llvm/IR/DataLayout.h @@ -108,13 +108,6 @@ struct PointerAlignElem { /// generating LLVM IR is required to generate the right target data for the /// target being codegen'd to. class DataLayout { -public: - enum class FunctionPtrAlignType { - /// The function pointer alignment is independent of the function alignment. - Independent, - /// The function pointer alignment is a multiple of the function alignment. - MultipleOfFunctionAlign, - }; private: /// Defaults to false. bool BigEndian; @@ -123,9 +116,6 @@ private: unsigned StackNaturalAlign; unsigned ProgramAddrSpace; - unsigned FunctionPtrAlign; - FunctionPtrAlignType TheFunctionPtrAlignType; - enum ManglingModeT { MM_None, MM_ELF, @@ -209,8 +199,6 @@ public: BigEndian = DL.isBigEndian(); AllocaAddrSpace = DL.AllocaAddrSpace; StackNaturalAlign = DL.StackNaturalAlign; - FunctionPtrAlign = DL.FunctionPtrAlign; - TheFunctionPtrAlignType = DL.TheFunctionPtrAlignType; ProgramAddrSpace = DL.ProgramAddrSpace; ManglingMode = DL.ManglingMode; LegalIntWidths = DL.LegalIntWidths; @@ -268,17 +256,6 @@ public: unsigned getStackAlignment() const { return StackNaturalAlign; } unsigned getAllocaAddrSpace() const { return AllocaAddrSpace; } - /// Returns the alignment of function pointers, which may or may not be - /// related to the alignment of functions. - /// \see getFunctionPtrAlignType - unsigned getFunctionPtrAlign() const { return FunctionPtrAlign; } - - /// Return the type of function pointer alignment. - /// \see getFunctionPtrAlign - FunctionPtrAlignType getFunctionPtrAlignType() const { - return TheFunctionPtrAlignType; - } - unsigned getProgramAddressSpace() const { return ProgramAddrSpace; } bool hasMicrosoftFastStdCallMangling() const { diff --git a/lib/IR/ConstantFold.cpp b/lib/IR/ConstantFold.cpp index 3784405ecb0..037f120f47d 100644 --- a/lib/IR/ConstantFold.cpp +++ b/lib/IR/ConstantFold.cpp @@ -26,7 +26,6 @@ #include "llvm/IR/GlobalAlias.h" #include "llvm/IR/GlobalVariable.h" #include "llvm/IR/Instructions.h" -#include "llvm/IR/Module.h" #include "llvm/IR/Operator.h" #include "llvm/IR/PatternMatch.h" #include "llvm/Support/ErrorHandling.h" @@ -1077,29 +1076,10 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1, isa(CE1->getOperand(0))) { GlobalValue *GV = cast(CE1->getOperand(0)); - unsigned GVAlign; - - if (Module *TheModule = GV->getParent()) { - GVAlign = GV->getPointerAlignment(TheModule->getDataLayout()); - - // If the function alignment is not specified then assume that it - // is 4. - // This is dangerous; on x86, the alignment of the pointer - // corresponds to the alignment of the function, but might be less - // than 4 if it isn't explicitly specified. - // However, a fix for this behaviour was reverted because it - // increased code size (see https://reviews.llvm.org/D55115) - // FIXME: This code should be deleted once existing targets have - // appropriate defaults - if (GVAlign == 0U && isa(GV)) - GVAlign = 4U; - } else if (isa(GV)) { - // Without a datalayout we have to assume the worst case: that the - // function pointer isn't aligned at all. - GVAlign = 0U; - } else { - GVAlign = GV->getAlignment(); - } + // Functions are at least 4-byte aligned. + unsigned GVAlign = GV->getAlignment(); + if (isa(GV)) + GVAlign = std::max(GVAlign, 4U); if (GVAlign > 1) { unsigned DstWidth = CI2->getType()->getBitWidth(); diff --git a/lib/IR/DataLayout.cpp b/lib/IR/DataLayout.cpp index 943f5381c64..2644214a49c 100644 --- a/lib/IR/DataLayout.cpp +++ b/lib/IR/DataLayout.cpp @@ -184,8 +184,6 @@ void DataLayout::reset(StringRef Desc) { AllocaAddrSpace = 0; StackNaturalAlign = 0; ProgramAddrSpace = 0; - FunctionPtrAlign = 0; - TheFunctionPtrAlignType = FunctionPtrAlignType::Independent; ManglingMode = MM_None; NonIntegralAddressSpaces.clear(); @@ -381,22 +379,6 @@ void DataLayout::parseSpecifier(StringRef Desc) { StackNaturalAlign = inBytes(getInt(Tok)); break; } - case 'F': { - switch (Tok.front()) { - case 'i': - TheFunctionPtrAlignType = FunctionPtrAlignType::Independent; - break; - case 'n': - TheFunctionPtrAlignType = FunctionPtrAlignType::MultipleOfFunctionAlign; - break; - default: - report_fatal_error("Unknown function pointer alignment type in " - "datalayout string"); - } - Tok = Tok.substr(1); - FunctionPtrAlign = inBytes(getInt(Tok)); - break; - } case 'P': { // Function address space. ProgramAddrSpace = getAddrSpace(Tok); break; @@ -450,8 +432,6 @@ bool DataLayout::operator==(const DataLayout &Other) const { AllocaAddrSpace == Other.AllocaAddrSpace && StackNaturalAlign == Other.StackNaturalAlign && ProgramAddrSpace == Other.ProgramAddrSpace && - FunctionPtrAlign == Other.FunctionPtrAlign && - TheFunctionPtrAlignType == Other.TheFunctionPtrAlignType && ManglingMode == Other.ManglingMode && LegalIntWidths == Other.LegalIntWidths && Alignments == Other.Alignments && Pointers == Other.Pointers; diff --git a/lib/IR/Value.cpp b/lib/IR/Value.cpp index 28263ede39d..38eed76fe45 100644 --- a/lib/IR/Value.cpp +++ b/lib/IR/Value.cpp @@ -648,16 +648,10 @@ unsigned Value::getPointerAlignment(const DataLayout &DL) const { unsigned Align = 0; if (auto *GO = dyn_cast(this)) { - if (isa(GO)) { - switch (DL.getFunctionPtrAlignType()) { - case DataLayout::FunctionPtrAlignType::Independent: - return DL.getFunctionPtrAlign(); - case DataLayout::FunctionPtrAlignType::MultipleOfFunctionAlign: - return std::max(DL.getFunctionPtrAlign(), GO->getAlignment()); - default: - llvm_unreachable("unknown function pointer align type"); - } - } + // Don't make any assumptions about function pointer alignment. Some + // targets use the LSBs to store additional information. + if (isa(GO)) + return 0; Align = GO->getAlignment(); if (Align == 0) { if (auto *GVar = dyn_cast(GO)) { diff --git a/lib/Target/ARM/ARMTargetMachine.cpp b/lib/Target/ARM/ARMTargetMachine.cpp index 401843c1e0f..9954eee2e5f 100644 --- a/lib/Target/ARM/ARMTargetMachine.cpp +++ b/lib/Target/ARM/ARMTargetMachine.cpp @@ -141,10 +141,6 @@ static std::string computeDataLayout(const Triple &TT, StringRef CPU, // Pointers are 32 bits and aligned to 32 bits. Ret += "-p:32:32"; - // Function pointers are aligned to 8 bits (because the LSB stores the - // ARM/Thumb state). - Ret += "-Fi8"; - // ABIs other than APCS have 64 bit integers with natural alignment. if (ABI != ARMBaseTargetMachine::ARM_ABI_APCS) Ret += "-i64:64"; diff --git a/unittests/IR/CMakeLists.txt b/unittests/IR/CMakeLists.txt index c3cdf90c0ef..a823407169f 100644 --- a/unittests/IR/CMakeLists.txt +++ b/unittests/IR/CMakeLists.txt @@ -13,7 +13,6 @@ add_llvm_unittest(IRTests CFGBuilder.cpp ConstantRangeTest.cpp ConstantsTest.cpp - DataLayoutTest.cpp DebugInfoTest.cpp DebugTypeODRUniquingTest.cpp DominatorTreeTest.cpp diff --git a/unittests/IR/ConstantsTest.cpp b/unittests/IR/ConstantsTest.cpp index c0fe18b1182..6b26b38e35e 100644 --- a/unittests/IR/ConstantsTest.cpp +++ b/unittests/IR/ConstantsTest.cpp @@ -475,105 +475,5 @@ TEST(ConstantsTest, BitcastToGEP) { ASSERT_EQ(cast(C)->getOpcode(), Instruction::BitCast); } -bool foldFuncPtrAndConstToNull(LLVMContext &Context, Module *TheModule, - uint64_t AndValue, unsigned FunctionAlign = 0) { - Type *VoidType(Type::getVoidTy(Context)); - FunctionType *FuncType(FunctionType::get(VoidType, false)); - Function *Func(Function::Create( - FuncType, GlobalValue::ExternalLinkage, "", TheModule)); - - if (FunctionAlign) Func->setAlignment(FunctionAlign); - - IntegerType *ConstantIntType(Type::getInt32Ty(Context)); - ConstantInt *TheConstant(ConstantInt::get(ConstantIntType, AndValue)); - - Constant *TheConstantExpr( - ConstantExpr::getPtrToInt(Func, ConstantIntType)); - - return ConstantExpr::get(Instruction::And, TheConstantExpr, - TheConstant)->isNullValue(); -} - -TEST(ConstantsTest, FoldFunctionPtrAlignUnknownAnd2) { - LLVMContext Context; - Module TheModule("TestModule", Context); - // When the DataLayout doesn't specify a function pointer alignment we - // assume in this case that it is 4 byte aligned. This is a bug but we can't - // fix it directly because it causes a code size regression on X86. - // FIXME: This test should be changed once existing targets have - // appropriate defaults. See associated FIXME in ConstantFoldBinaryInstruction - ASSERT_TRUE(foldFuncPtrAndConstToNull(Context, &TheModule, 2)); -} - -TEST(ConstantsTest, DontFoldFunctionPtrAlignUnknownAnd4) { - LLVMContext Context; - Module TheModule("TestModule", Context); - ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, &TheModule, 4)); -} - -TEST(ConstantsTest, FoldFunctionPtrAlign4) { - LLVMContext Context; - Module TheModule("TestModule", Context); - const char* AlignmentStrings[] = { "Fi32", "Fn32" }; - - for (unsigned AndValue = 1; AndValue <= 2; ++AndValue) { - for (const char *AlignmentString : AlignmentStrings) { - TheModule.setDataLayout(AlignmentString); - ASSERT_TRUE(foldFuncPtrAndConstToNull(Context, &TheModule, AndValue)); - } - } -} - -TEST(ConstantsTest, DontFoldFunctionPtrAlign1) { - LLVMContext Context; - Module TheModule("TestModule", Context); - const char* AlignmentStrings[] = { "Fi8", "Fn8" }; - - for (const char* AlignmentString : AlignmentStrings) { - TheModule.setDataLayout(AlignmentString); - ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, &TheModule, 2)); - } -} - -TEST(ConstantsTest, FoldFunctionAlign4PtrAlignMultiple) { - LLVMContext Context; - Module TheModule("TestModule", Context); - TheModule.setDataLayout("Fn8"); - ASSERT_TRUE(foldFuncPtrAndConstToNull(Context, &TheModule, 2, 4)); -} - -TEST(ConstantsTest, DontFoldFunctionAlign4PtrAlignIndependent) { - LLVMContext Context; - Module TheModule("TestModule", Context); - TheModule.setDataLayout("Fi8"); - ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, &TheModule, 2, 4)); -} - -TEST(ConstantsTest, DontFoldFunctionPtrIfNoModule) { - LLVMContext Context; - // Even though the function is explicitly 4 byte aligned, in the absence of a - // DataLayout we can't assume that the function pointer is aligned. - ASSERT_FALSE(foldFuncPtrAndConstToNull(Context, nullptr, 2, 4)); -} - -TEST(ConstantsTest, FoldGlobalVariablePtr) { - LLVMContext Context; - - - IntegerType *IntType(Type::getInt32Ty(Context)); - - GlobalVariable Global(IntType, true, GlobalValue::ExternalLinkage); - - Global.setAlignment(4); - - ConstantInt *TheConstant(ConstantInt::get(IntType, 2)); - - Constant *TheConstantExpr( - ConstantExpr::getPtrToInt(&Global, IntType)); - - ASSERT_TRUE(ConstantExpr::get( \ - Instruction::And, TheConstantExpr, TheConstant)->isNullValue()); -} - } // end anonymous namespace } // end namespace llvm diff --git a/unittests/IR/DataLayoutTest.cpp b/unittests/IR/DataLayoutTest.cpp deleted file mode 100644 index e7ed70b7de5..00000000000 --- a/unittests/IR/DataLayoutTest.cpp +++ /dev/null @@ -1,47 +0,0 @@ -//===- ConstantRangeTest.cpp - ConstantRange tests ------------------------===// -// -// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. -// See https://llvm.org/LICENSE.txt for license information. -// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception -// -//===----------------------------------------------------------------------===// - -#include "llvm/IR/DataLayout.h" -#include "gtest/gtest.h" - -using namespace llvm; - -namespace { - -TEST(DataLayoutTest, FunctionPtrAlign) { - EXPECT_EQ(0U, DataLayout("").getFunctionPtrAlign()); - EXPECT_EQ(1U, DataLayout("Fi8").getFunctionPtrAlign()); - EXPECT_EQ(2U, DataLayout("Fi16").getFunctionPtrAlign()); - EXPECT_EQ(4U, DataLayout("Fi32").getFunctionPtrAlign()); - EXPECT_EQ(8U, DataLayout("Fi64").getFunctionPtrAlign()); - EXPECT_EQ(1U, DataLayout("Fn8").getFunctionPtrAlign()); - EXPECT_EQ(2U, DataLayout("Fn16").getFunctionPtrAlign()); - EXPECT_EQ(4U, DataLayout("Fn32").getFunctionPtrAlign()); - EXPECT_EQ(8U, DataLayout("Fn64").getFunctionPtrAlign()); - EXPECT_EQ(DataLayout::FunctionPtrAlignType::Independent, \ - DataLayout("").getFunctionPtrAlignType()); - EXPECT_EQ(DataLayout::FunctionPtrAlignType::Independent, \ - DataLayout("Fi8").getFunctionPtrAlignType()); - EXPECT_EQ(DataLayout::FunctionPtrAlignType::MultipleOfFunctionAlign, \ - DataLayout("Fn8").getFunctionPtrAlignType()); - EXPECT_EQ(DataLayout("Fi8"), DataLayout("Fi8")); - EXPECT_NE(DataLayout("Fi8"), DataLayout("Fi16")); - EXPECT_NE(DataLayout("Fi8"), DataLayout("Fn8")); - - DataLayout a(""), b("Fi8"), c("Fn8"); - EXPECT_NE(a, b); - EXPECT_NE(a, c); - EXPECT_NE(b, c); - - a = b; - EXPECT_EQ(a, b); - a = c; - EXPECT_EQ(a, c); -} - -} // anonymous namespace diff --git a/unittests/IR/FunctionTest.cpp b/unittests/IR/FunctionTest.cpp index c68b064afe3..10a359ff64b 100644 --- a/unittests/IR/FunctionTest.cpp +++ b/unittests/IR/FunctionTest.cpp @@ -129,29 +129,4 @@ TEST(FunctionTest, setSection) { EXPECT_TRUE(F->hasSection()); } -TEST(FunctionTest, GetPointerAlignment) { - LLVMContext Context; - Type *VoidType(Type::getVoidTy(Context)); - FunctionType *FuncType(FunctionType::get(VoidType, false)); - Function *Func = Function::Create( - FuncType, GlobalValue::ExternalLinkage); - EXPECT_EQ(0U, Func->getPointerAlignment(DataLayout(""))); - EXPECT_EQ(1U, Func->getPointerAlignment(DataLayout("Fi8"))); - EXPECT_EQ(1U, Func->getPointerAlignment(DataLayout("Fn8"))); - EXPECT_EQ(2U, Func->getPointerAlignment(DataLayout("Fi16"))); - EXPECT_EQ(2U, Func->getPointerAlignment(DataLayout("Fn16"))); - EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fi32"))); - EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fn32"))); - - Func->setAlignment(4U); - - EXPECT_EQ(0U, Func->getPointerAlignment(DataLayout(""))); - EXPECT_EQ(1U, Func->getPointerAlignment(DataLayout("Fi8"))); - EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fn8"))); - EXPECT_EQ(2U, Func->getPointerAlignment(DataLayout("Fi16"))); - EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fn16"))); - EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fi32"))); - EXPECT_EQ(4U, Func->getPointerAlignment(DataLayout("Fn32"))); -} - } // end namespace -- 2.50.1