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[clang][driver] Use $ prefix with config file options to have them added after all of the command line options (#117573)
Currently, if a -l (or -Wl,) flag is added into a config file (e.g. clang.cfg), it is situated before any object file in the effective command line. If the library requested by given -l flag is static, its symbols will not be made visible to any of the object files provided by the user. Also, the presence of any of the linker flags in a config file confuses the driver whenever the user invokes clang without any parameters (see issue #67209). This patch attempts to solve both of the problems, by allowing a split of the arguments list into two parts. The head part of the list will be used as before, but the tail part will be appended after the command line flags provided by the user and only when it is known that the linking should occur. The $-prefixed arguments will be added to the tail part.
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‎clang/docs/UsersManual.rst‎

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@@ -1059,6 +1059,16 @@ In this way, the user may only need to specify a root configuration file with
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-L <CFGDIR>/lib
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-T <CFGDIR>/ldscripts/link.ld
10611061

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Usually, config file options are placed before command-line options, regardless
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of the actual operation to be performed. The exception is being made for the
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options prefixed with the ``$`` character. These will be used only when linker
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is being invoked, and added after all of the command-line specified linker
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inputs. Here is some example of ``$``-prefixed options:
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::
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$-Wl,-Bstatic $-lm
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$-Wl,-Bshared
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Language and Target-Independent Features
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========================================
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‎clang/include/clang/Driver/Driver.h‎

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@@ -297,8 +297,11 @@ class Driver {
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/// Object that stores strings read from configuration file.
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llvm::StringSaver Saver;
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300-
/// Arguments originated from configuration file.
301-
std::unique_ptr<llvm::opt::InputArgList> CfgOptions;
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/// Arguments originated from configuration file (head part).
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std::unique_ptr<llvm::opt::InputArgList> CfgOptionsHead;
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/// Arguments originated from configuration file (tail part).
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std::unique_ptr<llvm::opt::InputArgList> CfgOptionsTail;
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/// Arguments originated from command line.
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std::unique_ptr<llvm::opt::InputArgList> CLOptions;

‎clang/lib/Driver/Driver.cpp‎

Lines changed: 49 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -1039,34 +1039,59 @@ bool Driver::readConfigFile(StringRef FileName,
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}
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// Try reading the given file.
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SmallVector<const char *, 32> NewCfgArgs;
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if (llvm::Error Err = ExpCtx.readConfigFile(FileName, NewCfgArgs)) {
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SmallVector<const char *, 32> NewCfgFileArgs;
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if (llvm::Error Err = ExpCtx.readConfigFile(FileName, NewCfgFileArgs)) {
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Diag(diag::err_drv_cannot_read_config_file)
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<< FileName << toString(std::move(Err));
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return true;
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}
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// Populate head and tail lists. The tail list is used only when linking.
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SmallVector<const char *, 32> NewCfgHeadArgs, NewCfgTailArgs;
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for (const char *Opt : NewCfgFileArgs) {
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// An $-prefixed option should go to the tail list.
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if (Opt[0] == '$' && Opt[1])
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NewCfgTailArgs.push_back(Opt + 1);
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else
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NewCfgHeadArgs.push_back(Opt);
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}
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// Read options from config file.
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llvm::SmallString<128> CfgFileName(FileName);
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llvm::sys::path::native(CfgFileName);
1052-
bool ContainErrors;
1053-
auto NewOptions = std::make_unique<InputArgList>(
1054-
ParseArgStrings(NewCfgArgs, /*UseDriverMode=*/true, ContainErrors));
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bool ContainErrors = false;
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auto NewHeadOptions = std::make_unique<InputArgList>(
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ParseArgStrings(NewCfgHeadArgs, /*UseDriverMode=*/true, ContainErrors));
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if (ContainErrors)
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return true;
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auto NewTailOptions = std::make_unique<InputArgList>(
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ParseArgStrings(NewCfgTailArgs, /*UseDriverMode=*/true, ContainErrors));
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if (ContainErrors)
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return true;
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// Claim all arguments that come from a configuration file so that the driver
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// does not warn on any that is unused.
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for (Arg *A : *NewOptions)
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for (Arg *A : *NewHeadOptions)
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A->claim();
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for (Arg *A : *NewTailOptions)
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A->claim();
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1063-
if (!CfgOptions)
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CfgOptions = std::move(NewOptions);
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if (!CfgOptionsHead)
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CfgOptionsHead = std::move(NewHeadOptions);
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else {
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// If this is a subsequent config file, append options to the previous one.
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for (auto *Opt : *NewHeadOptions)
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appendOneArg(*CfgOptionsHead, Opt);
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}
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if (!CfgOptionsTail)
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CfgOptionsTail = std::move(NewTailOptions);
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else {
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// If this is a subsequent config file, append options to the previous one.
1067-
for (auto *Opt : *NewOptions)
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appendOneArg(*CfgOptions, Opt);
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for (auto *Opt : *NewTailOptions)
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appendOneArg(*CfgOptionsTail, Opt);
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}
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10701095
ConfigFiles.push_back(std::string(CfgFileName));
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return false;
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}
@@ -1243,13 +1268,14 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
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// Try parsing configuration file.
12441269
if (!ContainsError)
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ContainsError = loadConfigFiles();
1246-
bool HasConfigFile = !ContainsError && (CfgOptions.get() != nullptr);
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bool HasConfigFileHead = !ContainsError && CfgOptionsHead;
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bool HasConfigFileTail = !ContainsError && CfgOptionsTail;
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// All arguments, from both config file and command line.
1249-
InputArgList Args = std::move(HasConfigFile ? std::move(*CfgOptions)
1250-
: std::move(*CLOptions));
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InputArgList Args =
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HasConfigFileHead ? std::move(*CfgOptionsHead) : std::move(*CLOptions);
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1252-
if (HasConfigFile)
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if (HasConfigFileHead)
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for (auto *Opt : *CLOptions)
12541280
if (!Opt->getOption().matches(options::OPT_config))
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appendOneArg(Args, Opt);
@@ -1540,6 +1566,15 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
15401566
// Construct the list of inputs.
15411567
InputList Inputs;
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BuildInputs(C->getDefaultToolChain(), *TranslatedArgs, Inputs);
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if (HasConfigFileTail && Inputs.size()) {
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Arg *FinalPhaseArg;
1571+
if (getFinalPhase(*TranslatedArgs, &FinalPhaseArg) == phases::Link) {
1572+
DerivedArgList TranslatedLinkerIns(*CfgOptionsTail);
1573+
for (Arg *A : *CfgOptionsTail)
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TranslatedLinkerIns.append(A);
1575+
BuildInputs(C->getDefaultToolChain(), TranslatedLinkerIns, Inputs);
1576+
}
1577+
}
15431578

15441579
// Populate the tool chains for the offloading devices, if any.
15451580
CreateOffloadingDeviceToolChains(*C, Inputs);

‎clang/test/Driver/Inputs/config-l.cfg‎

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@@ -0,0 +1,3 @@
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-Wall $-lm
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-Wl,--as-needed $-Wl,-Bstatic
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$-lhappy $-Wl,-Bdynamic

‎clang/test/Driver/config-file.c‎

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@@ -82,3 +82,29 @@
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// CHECK-TWO-CONFIGS: -isysroot
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// CHECK-TWO-CONFIGS-SAME: /opt/data
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// CHECK-TWO-CONFIGS-SAME: -Wall
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//--- The linker input flags should be moved to the end of input list and appear only when linking.
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// RUN: %clang --target=aarch64-unknown-linux-gnu --config %S/Inputs/config-l.cfg %s -lmylib -Wl,foo.a -### 2>&1 | FileCheck %s -check-prefix CHECK-LINKING
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// RUN: %clang --target=aarch64-unknown-linux-gnu --config %S/Inputs/config-l.cfg -fopenmp %s -lmylib -Wl,foo.a -### 2>&1 | FileCheck %s -check-prefix CHECK-LINKING-LIBOMP-GOES-AFTER
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// RUN: %clang --target=aarch64-unknown-linux-gnu --config %S/Inputs/config-l.cfg -S %s -### 2>&1 | FileCheck %s -check-prefix CHECK-NOLINKING
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// RUN: %clang --target=aarch64-unknown-linux-gnu --config %S/Inputs/config-l.cfg -fopenmp -S %s -### 2>&1 | FileCheck %s -check-prefix CHECK-NOLINKING-OPENMP
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// RUN: %clang --target=x86_64-pc-windows-msvc --config %S/Inputs/config-l.cfg %s -lmylib -Wl,foo.lib -### 2>&1 | FileCheck %s -check-prefix CHECK-LINKING-MSVC
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// RUN: %clang --target=x86_64-pc-windows-msvc --config %S/Inputs/config-l.cfg -S %s -### 2>&1 | FileCheck %s -check-prefix CHECK-NOLINKING-MSVC
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// CHECK-LINKING: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
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// CHECK-LINKING: "-Wall"
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// CHECK-LINKING: "--as-needed" "{{.*}}-{{.*}}.o" "-lmylib" "foo.a" "-lm" "-Bstatic" "-lhappy" "-Bdynamic"
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// CHECK-LINKING-LIBOMP-GOES-AFTER: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
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// CHECK-LINKING-LIBOMP-GOES-AFTER: "-Wall" {{.*}}"-fopenmp"
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// CHECK-LINKING-LIBOMP-GOES-AFTER: "--as-needed" "{{.*}}-{{.*}}.o" "-lmylib" "foo.a" "-lm" "-Bstatic" "-lhappy" "-Bdynamic" {{.*}}"-lomp"
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// CHECK-NOLINKING: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
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// CHECK-NOLINKING: "-Wall"
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// CHECK-NOLINKING-NO: "-lm" "-Bstatic" "-lhappy" "-Bdynamic"
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// CHECK-NOLINKING-OPENMP: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
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// CHECK-NOLINKING-OPENMP: "-Wall" {{.*}}"-fopenmp"
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// CHECK-NOLINKING-OPENMP-NO: "-lm" "-Bstatic" "-lhappy" "-Bdynamic" {{.*}}"-lomp"
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// CHECK-LINKING-MSVC: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
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// CHECK-LINKING-MSVC: "-Wall"
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// CHECK-LINKING-MSVC: "--as-needed" "{{.*}}-{{.*}}.o" "mylib.lib" "foo.lib" "m.lib" "-Bstatic" "happy.lib" "-Bdynamic"
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// CHECK-NOLINKING-MSVC: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
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// CHECK-NOLINKING-MSVC: "-Wall"
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// CHECK-NOLINKING-MSVC-NO: "m.lib" "-Bstatic" "happy.lib" "-Bdynamic"

‎flang/test/Driver/Inputs/config-l.cfg‎

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@@ -0,0 +1,3 @@
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-ffast-math $-lm
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-Wl,--as-needed $-Wl,-Bstatic
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$-lhappy $-Wl,-Bdynamic

‎flang/test/Driver/config-file.f90‎

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@@ -61,3 +61,29 @@
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! CHECK-TWO-CONFIGS-NEXT: Configuration file: {{.*}}Inputs{{.}}config2{{.}}config-4.cfg
6262
! CHECK-TWO-CONFIGS: -ffp-contract=fast
6363
! CHECK-TWO-CONFIGS: -O3
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!--- The linker input flags should be moved to the end of input list and appear only when linking.
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! RUN: %flang --target=aarch64-unknown-linux-gnu --config %S/Inputs/config-l.cfg %s -lmylib -Wl,foo.a -### 2>&1 | FileCheck %s -check-prefix CHECK-LINKING
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! RUN: %flang --target=aarch64-unknown-linux-gnu --config %S/Inputs/config-l.cfg -fopenmp %s -lmylib -Wl,foo.a -### 2>&1 | FileCheck %s -check-prefix CHECK-LINKING-LIBOMP-GOES-AFTER
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! RUN: %flang --target=aarch64-unknown-linux-gnu --config %S/Inputs/config-l.cfg -S %s -### 2>&1 | FileCheck %s -check-prefix CHECK-NOLINKING
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! RUN: %flang --target=aarch64-unknown-linux-gnu --config %S/Inputs/config-l.cfg -fopenmp -S %s -### 2>&1 | FileCheck %s -check-prefix CHECK-NOLINKING-OPENMP
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! RUN: %flang --target=x86_64-pc-windows-msvc --config %S/Inputs/config-l.cfg %s -lmylib -Wl,foo.lib -### 2>&1 | FileCheck %s -check-prefix CHECK-LINKING-MSVC
71+
! RUN: %flang --target=x86_64-pc-windows-msvc --config %S/Inputs/config-l.cfg -S %s -### 2>&1 | FileCheck %s -check-prefix CHECK-NOLINKING-MSVC
72+
! CHECK-LINKING: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
73+
! CHECK-LINKING: "-ffast-math"
74+
! CHECK-LINKING: "--as-needed" "{{.*}}-{{.*}}.o" "-lmylib" "foo.a" "-lm" "-Bstatic" "-lhappy" "-Bdynamic"
75+
! CHECK-LINKING-LIBOMP-GOES-AFTER: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
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! CHECK-LINKING-LIBOMP-GOES-AFTER: "-ffast-math" {{.*}}"-fopenmp"
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! CHECK-LINKING-LIBOMP-GOES-AFTER: "--as-needed" "{{.*}}-{{.*}}.o" "-lmylib" "foo.a" "-lm" "-Bstatic" "-lhappy" "-Bdynamic" {{.*}}"-lomp"
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! CHECK-NOLINKING: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
79+
! CHECK-NOLINKING: "-ffast-math"
80+
! CHECK-NOLINKING-NO: "-lm" "-Bstatic" "-lhappy" "-Bdynamic"
81+
! CHECK-NOLINKING-OPENMP: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
82+
! CHECK-NOLINKING-OPENMP: "-ffast-math" {{.*}}"-fopenmp"
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! CHECK-NOLINKING-OPENMP-NO: "-lm" "-Bstatic" "-lhappy" "-Bdynamic" {{.}}"-lomp"
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! CHECK-LINKING-MSVC: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
85+
! CHECK-LINKING-MSVC: "-ffast-math"
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! CHECK-LINKING-MSVC: "--as-needed" "{{.*}}-{{.*}}.o" "mylib.lib" "foo.lib" "m.lib" "-Bstatic" "happy.lib" "-Bdynamic"
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! CHECK-NOLINKING-MSVC: Configuration file: {{.*}}Inputs{{.}}config-l.cfg
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! CHECK-NOLINKING-MSVC: "-ffast-math"
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! CHECK-NOLINKING-MSVC-NO: "m.lib" "-Bstatic" "happy.lib" "-Bdynamic"

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