Restore part of "[ThinLTO] Prevent exporting of locals used/defined in module level...

This restores the part of r286297 that didn't require adding a
dependency from the Analysis to Object library. There are two parts
to the original fix, and this will address the handling for the case
where locals are used in module level asm.

The part that requires functionality in libObject handles local defs
in module level asm, and was reverted because our downstream build
of clang builds lib/Bitcode into a single library, and this new
dependency introduced a cycle there. I am trying to get that fixed
(see D26502), so for now that change isn't being restored

llvm-svn: 286475

diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
index 09d18eb..a3f4307 100644 (file)
--- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -194,12 +194,22 @@ 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<GlobalValue *, 8> LocalsUsed;
   SmallPtrSet<GlobalValue *, 8> Used;
+  // First collect those in the llvm.used set.
   collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
-  SmallPtrSet<GlobalValue *, 8> 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);

diff --git a/llvm/test/ThinLTO/X86/Inputs/module_asm2.ll b/llvm/test/ThinLTO/X86/Inputs/module_asm2.ll
new file mode 100644 (file)
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 (file)
index 0000000..3ec0945
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/module_asm2.ll
@@ -0,0 +1,87 @@
+; 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. We have to check in the importing module, however, as we
+; don't currently generate a summary for values defined in module asm,
+; so they couldn't get promoted even if we exported a reference.
+; 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 b and x are likewise not exported (imported as refs
+; into the other module), since they can't be promoted. Additionally,
+; referencing functions func2 and func3 should not have been
+; imported.
+; FIXME: Likewise, foo should not be exported, along with referencing function
+; func1. However, this relies on being able to add a dependence from
+; libAnalysis to libObject, which is currently blocked (see revert of
+; r286297).
+; NM1-NOT: b
+; NM1-NOT: x
+; NM1-DAG: U func2
+; NM1-DAG: U func3
+; NM1-DAG: T main
+; 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
+}