[ThinLTO] Import local variables from the same module as caller
Summary:
We can sometimes end up with multiple copies of a local variable that
have the same GUID in the index. This happens when there are local
variables with the same name that are in different source files having the
same name/path at compile time (but compiled into different bitcode objects).
In this case make sure we import the copy in the caller's module.
This enables importing both of the variables having the same GUID
(but which will have different promoted names since the module paths,
and therefore the module hashes, will be distinct).
Importing the wrong copy is particularly problematic for read only
variables, since we must import them as a local copy whenever
referenced. Otherwise we get undefs at link time.
Note that the llvm-lto.cpp and ThinLTOCodeGenerator changes are needed
for testing the distributed index case via clang, which will be sent as
a separate clang-side patch shortly. We were previously not doing the
dead code/read only computation before computing imports when testing
distributed index generation (like it was for testing importing and
other ThinLTO mechanisms alone).
Reviewers: evgeny777
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, dang, llvm-commits
Differential Revision: https://reviews.llvm.org/D55047
llvm-svn: 347886
2018-11-30 01:02:42 +08:00
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; Test handling when two files with the same source file name contain
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; static read only variables with the same name (which will have the same GUID
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; in the combined index).
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; Do setup work for all below tests: generate bitcode and combined index
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; RUN: opt -module-summary -module-hash %s -o %t.bc
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; RUN: opt -module-summary -module-hash %p/Inputs/local_name_conflict_var1.ll -o %t2.bc
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; RUN: opt -module-summary -module-hash %p/Inputs/local_name_conflict_var2.ll -o %t3.bc
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; RUN: llvm-lto -thinlto-action=thinlink -o %t4.bc %t.bc %t2.bc %t3.bc
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; This module will import a() and b() which should cause the read only copy
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; of baz from each of those modules to be imported. Check that the both are
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; imported as local copies.
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; RUN: llvm-lto -thinlto-action=import -exported-symbol=main %t.bc -thinlto-index=%t4.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=IMPORT
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; IMPORT: @baz.llvm.{{.*}} = internal global i32 10
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; IMPORT: @baz.llvm.{{.*}} = internal global i32 10
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; ModuleID = 'local_name_conflict_var_main.o'
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source_filename = "local_name_conflict_var_main.c"
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2019-09-11 07:15:38 +08:00
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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[ThinLTO] Import local variables from the same module as caller
Summary:
We can sometimes end up with multiple copies of a local variable that
have the same GUID in the index. This happens when there are local
variables with the same name that are in different source files having the
same name/path at compile time (but compiled into different bitcode objects).
In this case make sure we import the copy in the caller's module.
This enables importing both of the variables having the same GUID
(but which will have different promoted names since the module paths,
and therefore the module hashes, will be distinct).
Importing the wrong copy is particularly problematic for read only
variables, since we must import them as a local copy whenever
referenced. Otherwise we get undefs at link time.
Note that the llvm-lto.cpp and ThinLTOCodeGenerator changes are needed
for testing the distributed index case via clang, which will be sent as
a separate clang-side patch shortly. We were previously not doing the
dead code/read only computation before computing imports when testing
distributed index generation (like it was for testing importing and
other ThinLTO mechanisms alone).
Reviewers: evgeny777
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, dang, llvm-commits
Differential Revision: https://reviews.llvm.org/D55047
llvm-svn: 347886
2018-11-30 01:02:42 +08:00
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target triple = "x86_64-unknown-linux-gnu"
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; Function Attrs: noinline nounwind uwtable
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define i32 @main() {
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entry:
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%call1 = call i32 (...) @a()
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%call2 = call i32 (...) @b()
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ret i32 0
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}
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declare i32 @a(...)
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declare i32 @b(...)
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