[lld] r337634 - Omit path to lld binary from lld's error, warning, and log output.

[Nico Weber via llvm-commits]

Author: nico
Date: Fri Jul 20 16:09:12 2018
New Revision: 337634

URL: http://llvm.org/viewvc/llvm-project?rev=337634&view=rev
Log:
Omit path to lld binary from lld's error, warning, and log output.

lld currently prepends the absolute path to itself to every diagnostic it
emits. This path can be longer than the diagnostic, and makes the actual error
message hard to read.

There isn't a good reason for printing this path: if you want to know which lld
you're running, pass -v to clang – chances are that if you're unsure of this,
you're not only unsure when it errors out. Some people want an indication that
the diagnostic is from the linker though, so instead print just the basename of
the linker's path.

Before:

```
$ out/bin/clang -target x86_64-unknown-linux -x c++ /dev/null -fuse-ld=lld 
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crt1.o: No such file or directory
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crti.o: No such file or directory
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crtbegin.o: No such file or directory
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lgcc
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lgcc_s
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lc
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lgcc
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: unable to find library -lgcc_s
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crtend.o: No such file or directory
/Users/thakis/src/llvm-mono/out/bin/ld.lld: error: cannot open crtn.o: No such file or directory
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```

After:

```
$ out/bin/clang -target x86_64-unknown-linux -x c++ /dev/null -fuse-ld=lld 
ld.lld: error: cannot open crt1.o: No such file or directory
ld.lld: error: cannot open crti.o: No such file or directory
ld.lld: error: cannot open crtbegin.o: No such file or directory
ld.lld: error: unable to find library -lgcc
ld.lld: error: unable to find library -lgcc_s
ld.lld: error: unable to find library -lc
ld.lld: error: unable to find library -lgcc
ld.lld: error: unable to find library -lgcc_s
ld.lld: error: cannot open crtend.o: No such file or directory
ld.lld: error: cannot open crtn.o: No such file or directory
clang: error: linker command failed with exit code 1 (use -v to see invocation)
```

https://reviews.llvm.org/D49189

Modified:
    lld/trunk/COFF/Driver.cpp
    lld/trunk/ELF/Driver.cpp
    lld/trunk/lib/Driver/DarwinLdDriver.cpp
    lld/trunk/wasm/Driver.cpp

Modified: lld/trunk/COFF/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Driver.cpp?rev=337634&r1=337633&r2=337634&view=diff
==============================================================================
--- lld/trunk/COFF/Driver.cpp (original)
+++ lld/trunk/COFF/Driver.cpp Fri Jul 20 16:09:12 2018
@@ -56,7 +56,7 @@ Configuration *Config;
 LinkerDriver *Driver;
 
 bool link(ArrayRef<const char *> Args, bool CanExitEarly, raw_ostream &Diag) {
-  errorHandler().LogName = Args[0];
+  errorHandler().LogName = sys::path::filename(Args[0]);
   errorHandler().ErrorOS = &Diag;
   errorHandler().ColorDiagnostics = Diag.has_colors();
   errorHandler().ErrorLimitExceededMsg =

Modified: lld/trunk/ELF/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=337634&r1=337633&r2=337634&view=diff
==============================================================================
--- lld/trunk/ELF/Driver.cpp (original)
+++ lld/trunk/ELF/Driver.cpp Fri Jul 20 16:09:12 2018
@@ -74,7 +74,7 @@ static void setConfigs(opt::InputArgList
 
 bool elf::link(ArrayRef<const char *> Args, bool CanExitEarly,
                raw_ostream &Error) {
-  errorHandler().LogName = Args[0];
+  errorHandler().LogName = sys::path::filename(Args[0]);
   errorHandler().ErrorLimitExceededMsg =
       "too many errors emitted, stopping now (use "
       "-error-limit=0 to see all errors)";

Modified: lld/trunk/lib/Driver/DarwinLdDriver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/Driver/DarwinLdDriver.cpp?rev=337634&r1=337633&r2=337634&view=diff
==============================================================================
--- lld/trunk/lib/Driver/DarwinLdDriver.cpp (original)
+++ lld/trunk/lib/Driver/DarwinLdDriver.cpp Fri Jul 20 16:09:12 2018
@@ -1143,7 +1143,7 @@ static void createFiles(MachOLinkingCont
 /// This is where the link is actually performed.
 bool link(llvm::ArrayRef<const char *> args, bool CanExitEarly,
           raw_ostream &Error) {
-  errorHandler().LogName = args[0];
+  errorHandler().LogName = llvm::sys::path::filename(args[0]);
   errorHandler().ErrorLimitExceededMsg =
       "too many errors emitted, stopping now (use "
       "'-error-limit 0' to see all errors)";

Modified: lld/trunk/wasm/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/Driver.cpp?rev=337634&r1=337633&r2=337634&view=diff
==============================================================================
--- lld/trunk/wasm/Driver.cpp (original)
+++ lld/trunk/wasm/Driver.cpp Fri Jul 20 16:09:12 2018
@@ -74,7 +74,7 @@ private:
 
 bool lld::wasm::link(ArrayRef<const char *> Args, bool CanExitEarly,
                      raw_ostream &Error) {
-  errorHandler().LogName = Args[0];
+  errorHandler().LogName = sys::path::filename(Args[0]);
   errorHandler().ErrorOS = &Error;
   errorHandler().ColorDiagnostics = Error.has_colors();
   errorHandler().ErrorLimitExceededMsg =