From 6955feebf31bb75e7055c7c0c1e6a2c698dfbe77 Mon Sep 17 00:00:00 2001 From: Teresa Johnson Date: Tue, 8 Nov 2016 21:53:35 +0000 Subject: [PATCH] [ThinLTO] Prevent exporting of locals used/defined in module level asm Summary: This patch uses the same approach added for inline asm in r285513 to similarly prevent promotion/renaming of locals used or defined in module level asm. All static global values defined in normal IR and used in module level asm should be included on either the llvm.used or llvm.compiler.used global. The former were already being flagged as NoRename in the summary, and I've simply added llvm.compiler.used values to this handling. Module level asm may also contain defs of values. We need to prevent export of any refs to local values defined in module level asm (e.g. a ref in normal IR), since that also requires renaming/promotion of the local. To do that, the summary index builder looks at all values in the module level asm string that are not marked Weak or Global, which is exactly the set of locals that are defined. A summary is created for each of these local defs and flagged as NoRename. This required adding handling to the BitcodeWriter to look at GV declarations to see if they have a summary (rather than skipping them all). Finally, added an assert to IRObjectFile::CollectAsmUndefinedRefs to ensure that an MCAsmParser is available, otherwise the module asm parse would silently fail. Initialized the asm parser in the opt tool for use in testing this fix. Fixes PR30610. Reviewers: mehdi_amini Subscribers: johanengelen, krasin, llvm-commits Differential Revision: https://reviews.llvm.org/D26146 llvm-svn: 286297 --- llvm/include/llvm/Support/TargetRegistry.h | 3 ++ llvm/lib/Analysis/LLVMBuild.txt | 2 +- llvm/lib/Analysis/ModuleSummaryAnalysis.cpp | 61 +++++++++++++++++++-- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | 23 +++++--- llvm/lib/Object/IRObjectFile.cpp | 3 +- llvm/test/LTO/X86/current-section.ll | 3 ++ llvm/test/ThinLTO/X86/Inputs/module_asm2.ll | 12 +++++ llvm/test/ThinLTO/X86/module_asm2.ll | 84 +++++++++++++++++++++++++++++ llvm/tools/opt/opt.cpp | 1 + 9 files changed, 179 insertions(+), 13 deletions(-) create mode 100644 llvm/test/ThinLTO/X86/Inputs/module_asm2.ll create mode 100644 llvm/test/ThinLTO/X86/module_asm2.ll diff --git a/llvm/include/llvm/Support/TargetRegistry.h b/llvm/include/llvm/Support/TargetRegistry.h index f868c07..954cdb1 100644 --- a/llvm/include/llvm/Support/TargetRegistry.h +++ b/llvm/include/llvm/Support/TargetRegistry.h @@ -280,6 +280,9 @@ public: /// hasMCAsmBackend - Check if this target supports .o generation. bool hasMCAsmBackend() const { return MCAsmBackendCtorFn != nullptr; } + /// hasMCAsmParser - Check if this target supports assembly parsing. + bool hasMCAsmParser() const { return MCAsmParserCtorFn != nullptr; } + /// @} /// @name Feature Constructors /// @{ diff --git a/llvm/lib/Analysis/LLVMBuild.txt b/llvm/lib/Analysis/LLVMBuild.txt index 08af5f3..15c757b 100644 --- a/llvm/lib/Analysis/LLVMBuild.txt +++ b/llvm/lib/Analysis/LLVMBuild.txt @@ -19,4 +19,4 @@ type = Library name = Analysis parent = Libraries -required_libraries = Core Support ProfileData +required_libraries = Core Support ProfileData Object diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp index 09d18eb..5cf4a89 100644 --- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp +++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp @@ -13,6 +13,7 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/ModuleSummaryAnalysis.h" +#include "llvm/ADT/Triple.h" #include "llvm/Analysis/BlockFrequencyInfo.h" #include "llvm/Analysis/BlockFrequencyInfoImpl.h" #include "llvm/Analysis/BranchProbabilityInfo.h" @@ -24,6 +25,7 @@ #include "llvm/IR/InstIterator.h" #include "llvm/IR/IntrinsicInst.h" #include "llvm/IR/ValueSymbolTable.h" +#include "llvm/Object/IRObjectFile.h" #include "llvm/Pass.h" using namespace llvm; @@ -194,12 +196,22 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex( ProfileSummaryInfo *PSI) { ModuleSummaryIndex Index; - // Identify the local values in the llvm.used set, which should not be - // exported as they would then require renaming and promotion, but we - // may have opaque uses e.g. in inline asm. + // Identify the local values in the llvm.used and llvm.compiler.used sets, + // which should not be exported as they would then require renaming and + // promotion, but we may have opaque uses e.g. in inline asm. We collect them + // here because we use this information to mark functions containing inline + // assembly calls as not importable. + SmallPtrSet LocalsUsed; SmallPtrSet Used; + // First collect those in the llvm.used set. collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false); - SmallPtrSet LocalsUsed; + for (auto *V : Used) { + if (V->hasLocalLinkage()) + LocalsUsed.insert(V); + } + Used.clear(); + // Next collect those in the llvm.compiler.used set. + collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ true); for (auto *V : Used) { if (V->hasLocalLinkage()) LocalsUsed.insert(V); @@ -244,6 +256,47 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex( Summary->setNoRename(); } + if (!M.getModuleInlineAsm().empty()) { + // Collect the local values defined by module level asm, and set up + // summaries for these symbols so that they can be marked as NoRename, + // to prevent export of any use of them in regular IR that would require + // renaming within the module level asm. Note we don't need to create a + // summary for weak or global defs, as they don't need to be flagged as + // NoRename, and defs in module level asm can't be imported anyway. + // Also, any values used but not defined within module level asm should + // be listed on the llvm.used or llvm.compiler.used global and marked as + // referenced from there. + // FIXME: Rename CollectAsmUndefinedRefs to something more general, as we + // are also using it to find the file-scope locals defined in module asm. + object::IRObjectFile::CollectAsmUndefinedRefs( + Triple(M.getTargetTriple()), M.getModuleInlineAsm(), + [&M, &Index](StringRef Name, object::BasicSymbolRef::Flags Flags) { + // Symbols not marked as Weak or Global are local definitions. + if (Flags & (object::BasicSymbolRef::SF_Weak || + object::BasicSymbolRef::SF_Global)) + return; + GlobalValue *GV = M.getNamedValue(Name); + if (!GV) + return; + assert(GV->isDeclaration() && "Def in module asm already has definition"); + GlobalValueSummary::GVFlags GVFlags(GlobalValue::InternalLinkage, + /* NoRename */ true, + /*IsNotViableToInline */ true); + // Create the appropriate summary type. + if (isa(GV)) { + std::unique_ptr Summary = + llvm::make_unique(GVFlags, 0); + Summary->setNoRename(); + Index.addGlobalValueSummary(Name, std::move(Summary)); + } else { + std::unique_ptr Summary = + llvm::make_unique(GVFlags); + Summary->setNoRename(); + Index.addGlobalValueSummary(Name, std::move(Summary)); + } + }); + } + return Index; } diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp index 8de61bc..7b49aac0 100644 --- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp +++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp @@ -3327,11 +3327,16 @@ void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord( void ModuleBitcodeWriter::writeModuleLevelReferences( const GlobalVariable &V, SmallVector &NameVals, unsigned FSModRefsAbbrev) { - // Only interested in recording variable defs in the summary. - if (V.isDeclaration()) + auto Summaries = + Index->findGlobalValueSummaryList(GlobalValue::getGUID(V.getName())); + if (Summaries == Index->end()) { + // Only declarations should not have a summary (a declaration might however + // have a summary if the def was in module level asm). + assert(V.isDeclaration()); return; + } + auto *Summary = Summaries->second.front().get(); NameVals.push_back(VE.getValueID(&V)); - auto *Summary = Index->getGlobalValueSummary(V); GlobalVarSummary *VS = cast(Summary); NameVals.push_back(getEncodedGVSummaryFlags(VS->flags())); @@ -3409,14 +3414,20 @@ void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() { // Iterate over the list of functions instead of the Index to // ensure the ordering is stable. for (const Function &F : M) { - if (F.isDeclaration()) - continue; // Summary emission does not support anonymous functions, they have to // renamed using the anonymous function renaming pass. if (!F.hasName()) report_fatal_error("Unexpected anonymous function when writing summary"); - auto *Summary = Index->getGlobalValueSummary(F); + auto Summaries = + Index->findGlobalValueSummaryList(GlobalValue::getGUID(F.getName())); + if (Summaries == Index->end()) { + // Only declarations should not have a summary (a declaration might + // however have a summary if the def was in module level asm). + assert(F.isDeclaration()); + continue; + } + auto *Summary = Summaries->second.front().get(); writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F), FSCallsAbbrev, FSCallsProfileAbbrev, F); } diff --git a/llvm/lib/Object/IRObjectFile.cpp b/llvm/lib/Object/IRObjectFile.cpp index 8769f8f..d9474b94 100644 --- a/llvm/lib/Object/IRObjectFile.cpp +++ b/llvm/lib/Object/IRObjectFile.cpp @@ -54,8 +54,7 @@ void IRObjectFile::CollectAsmUndefinedRefs( std::string Err; const Target *T = TargetRegistry::lookupTarget(TT.str(), Err); - if (!T) - return; + assert(T && T->hasMCAsmParser()); std::unique_ptr MRI(T->createMCRegInfo(TT.str())); if (!MRI) diff --git a/llvm/test/LTO/X86/current-section.ll b/llvm/test/LTO/X86/current-section.ll index 49eee49..69f8bfa 100644 --- a/llvm/test/LTO/X86/current-section.ll +++ b/llvm/test/LTO/X86/current-section.ll @@ -2,4 +2,7 @@ ; RUN: llvm-lto -o %t2 %t1 ; REQUIRES: default_triple +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + module asm ".align 4" diff --git a/llvm/test/ThinLTO/X86/Inputs/module_asm2.ll b/llvm/test/ThinLTO/X86/Inputs/module_asm2.ll new file mode 100644 index 0000000..e823277 --- /dev/null +++ b/llvm/test/ThinLTO/X86/Inputs/module_asm2.ll @@ -0,0 +1,12 @@ +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +define i32 @main({ i64, { i64, i8* }* } %unnamed) #0 { + %1 = call i32 @func1() #1 + %2 = call i32 @func2() #1 + %3 = call i32 @func3() #1 + ret i32 %1 +} +declare i32 @func1() #1 +declare i32 @func2() #1 +declare i32 @func3() #1 diff --git a/llvm/test/ThinLTO/X86/module_asm2.ll b/llvm/test/ThinLTO/X86/module_asm2.ll new file mode 100644 index 0000000..90ef75f --- /dev/null +++ b/llvm/test/ThinLTO/X86/module_asm2.ll @@ -0,0 +1,84 @@ +; Test to ensure that uses and defs in module level asm are handled +; appropriately. Specifically, we should conservatively block importing +; of any references to these values, as they can't be renamed. +; RUN: opt -module-summary %s -o %t1.bc +; RUN: opt -module-summary %p/Inputs/module_asm2.ll -o %t2.bc + +; RUN: llvm-lto -thinlto-action=run -exported-symbol=main -exported-symbol=func1 -exported-symbol=func2 -exported-symbol=func3 %t1.bc %t2.bc +; RUN: llvm-nm %t1.bc.thinlto.o | FileCheck %s --check-prefix=NM0 +; RUN: llvm-nm %t2.bc.thinlto.o | FileCheck %s --check-prefix=NM1 + +; RUN: llvm-lto2 %t1.bc %t2.bc -o %t.o -save-temps \ +; RUN: -r=%t1.bc,foo,plx \ +; RUN: -r=%t1.bc,b,pl \ +; RUN: -r=%t1.bc,x,pl \ +; RUN: -r=%t1.bc,func1,pl \ +; RUN: -r=%t1.bc,func2,pl \ +; RUN: -r=%t1.bc,func3,pl \ +; RUN: -r=%t2.bc,main,plx \ +; RUN: -r=%t2.bc,func1,l \ +; RUN: -r=%t2.bc,func2,l \ +; RUN: -r=%t2.bc,func3,l +; RUN: llvm-nm %t.o.0 | FileCheck %s --check-prefix=NM0 +; RUN: llvm-nm %t.o.1 | FileCheck %s --check-prefix=NM1 + +; Check that local values b and x, which are referenced on +; llvm.used and llvm.compiler.used, respectively, are not promoted. +; Similarly, foo which is defined in module level asm should not be +; promoted. +; NM0-DAG: d b +; NM0-DAG: d x +; NM0-DAG: t foo +; NM0-DAG: T func1 +; NM0-DAG: T func2 +; NM0-DAG: T func3 + +; Ensure that foo, b and x are likewise not exported (imported as refs +; into the other module), since they can't be promoted. Additionally, +; referencing functions func1, func2 and func3 should not have been +; imported. +; NM1-NOT: foo +; NM1-NOT: b +; NM1-NOT: x +; NM1-DAG: U func1 +; NM1-DAG: U func2 +; NM1-DAG: U func3 +; NM1-DAG: T main +; NM1-NOT: foo +; NM1-NOT: b +; NM1-NOT: x + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +@b = internal global i32 1, align 4 +@x = internal global i32 1, align 4 + +@llvm.compiler.used = appending global [1 x i8*] [i8* bitcast (i32* @b to i8*)], section "llvm.metadata" +@llvm.used = appending global [1 x i8*] [i8* bitcast (i32* @x to i8*)], section "llvm.metadata" + +module asm "\09.text" +module asm "\09.type\09foo,@function" +module asm "foo:" +module asm "\09movl b, %eax" +module asm "\09movl x, %edx" +module asm "\09ret " +module asm "\09.size\09foo, .-foo" +module asm "" + +declare i16 @foo() #0 + +define i32 @func1() #1 { + call i16 @foo() + ret i32 1 +} + +define i32 @func2() #1 { + %1 = load i32, i32* @b, align 4 + ret i32 %1 +} + +define i32 @func3() #1 { + %1 = load i32, i32* @x, align 4 + ret i32 %1 +} diff --git a/llvm/tools/opt/opt.cpp b/llvm/tools/opt/opt.cpp index ef4f975..0a42c13 100644 --- a/llvm/tools/opt/opt.cpp +++ b/llvm/tools/opt/opt.cpp @@ -364,6 +364,7 @@ int main(int argc, char **argv) { InitializeAllTargets(); InitializeAllTargetMCs(); InitializeAllAsmPrinters(); + InitializeAllAsmParsers(); // Initialize passes PassRegistry &Registry = *PassRegistry::getPassRegistry(); -- 2.7.4