From 5e047d9c91038480bbe0d11205aa3dcc4bf7dfd0 Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Wed, 17 Aug 2016 23:26:32 +0300
Subject: [PATCH 01/11] Write pdb info to a specific file.

---
 mesonbuild/backend/ninjabackend.py | 1 +
 mesonbuild/compilers.py            | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 15f298b1e7cd..cb007d458fa3 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -1521,6 +1521,7 @@ def generate_single_compile(self, target, outfile, src, is_generated=False, head
             commands+= compiler.get_include_args(i, False)
         if self.environment.coredata.base_options.get('b_pch', False):
             commands += self.get_pch_include_args(compiler, target)
+        commands += compiler.get_compile_debugfile_args(rel_obj)
         crstr = ''
         if target.is_cross:
             crstr = '_CROSS'
diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index d020033c5182..5a8f48a9fbcb 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -352,6 +352,11 @@ def get_cross_extra_flags(self, environment, *, compile, link):
     def get_colorout_args(self, colortype):
         return []
 
+    # Some compilers (msvc) write debug info to a separate file.
+    # These args specify where it should be written.
+    def get_compile_debugfile_args(self, rel_obj):
+        return []
+
 class CCompiler(Compiler):
     def __init__(self, exelist, version, is_cross, exe_wrapper=None):
         super().__init__(exelist, version)
@@ -1599,6 +1604,10 @@ def has_argument(self, arg, env):
             raise MesonException('Compiling test app failed.')
         return not(warning_text in stde or warning_text in stdo)
 
+    def get_compile_debugfile_args(self, rel_obj):
+        pdbarr = rel_obj.split('.')[:-1] + ['pdb']
+        return ['/Fd' + '.'.join(pdbarr)]
+
 class VisualStudioCPPCompiler(VisualStudioCCompiler):
     def __init__(self, exelist, version, is_cross, exe_wrap):
         VisualStudioCCompiler.__init__(self, exelist, version, is_cross, exe_wrap)

From b08581d394d0e0102bce2e51c46f16f2102dc8c7 Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Wed, 17 Aug 2016 23:50:50 +0300
Subject: [PATCH 02/11] Generate pdb files during linking.

---
 mesonbuild/backend/ninjabackend.py |  1 +
 mesonbuild/compilers.py            | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index cb007d458fa3..7c47ef4de4f6 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -1669,6 +1669,7 @@ def generate_link(self, target, outfile, outname, obj_list, linker, extra_args=[
                                                      linker)
         commands += linker.get_buildtype_linker_args(self.environment.coredata.get_builtin_option('buildtype'))
         commands += linker.get_option_link_args(self.environment.coredata.compiler_options)
+        commands += linker.get_link_debugfile_args(outname)
         if not(isinstance(target, build.StaticLibrary)):
             commands += self.environment.coredata.external_link_args[linker.get_language()]
         if isinstance(target, build.Executable):
diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index 5a8f48a9fbcb..744d75f8f6b9 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -357,6 +357,9 @@ def get_colorout_args(self, colortype):
     def get_compile_debugfile_args(self, rel_obj):
         return []
 
+    def get_link_debugfile_args(self, rel_obj):
+        return []
+
 class CCompiler(Compiler):
     def __init__(self, exelist, version, is_cross, exe_wrapper=None):
         super().__init__(exelist, version)
@@ -1608,6 +1611,10 @@ def get_compile_debugfile_args(self, rel_obj):
         pdbarr = rel_obj.split('.')[:-1] + ['pdb']
         return ['/Fd' + '.'.join(pdbarr)]
 
+    def get_link_debugfile_args(self, targetfile):
+        pdbarr = targetfile.split('.')[:-1] + ['pdb']
+        return ['/DEBUG', '/PDB:' + '.'.join(pdbarr)]
+
 class VisualStudioCPPCompiler(VisualStudioCCompiler):
     def __init__(self, exelist, version, is_cross, exe_wrap):
         VisualStudioCCompiler.__init__(self, exelist, version, is_cross, exe_wrap)
@@ -2284,6 +2291,10 @@ def unix_link_flags_to_native(self, args):
     def unix_compile_flags_to_native(self, args):
         return args[:]
 
+    def get_link_debugfile_args(self, targetfile):
+        pdbarr = targetfile.split('.')[:-1] + ['pdb']
+        return ['/DEBUG', '/PDB:' + '.'.join(pdbarr)]
+
 class ArLinker():
 
     def __init__(self, exelist):

From ccda29794b1802eba9dcd79ec2338407bb045fae Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Thu, 18 Aug 2016 00:12:54 +0300
Subject: [PATCH 03/11] Make pdb work with pch.

---
 mesonbuild/backend/ninjabackend.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 7c47ef4de4f6..a42db9fd5c65 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -1521,7 +1521,8 @@ def generate_single_compile(self, target, outfile, src, is_generated=False, head
             commands+= compiler.get_include_args(i, False)
         if self.environment.coredata.base_options.get('b_pch', False):
             commands += self.get_pch_include_args(compiler, target)
-        commands += compiler.get_compile_debugfile_args(rel_obj)
+
+        commands += compiler.get_compile_debugfile_args(self.get_target_filename_abs(target))
         crstr = ''
         if target.is_cross:
             crstr = '_CROSS'
@@ -1590,6 +1591,8 @@ def generate_msvc_pch_command(self, target, compiler, pch):
         just_name = os.path.split(header)[1]
         (objname, pch_args) = compiler.gen_pch_args(just_name, source, dst)
         commands += pch_args
+        tfilename = self.get_target_filename_abs(target)
+        commands += compiler.get_compile_debugfile_args(tfilename)
         dep = dst + '.' + compiler.get_depfile_suffix()
         return (commands, dep, dst, [objname])
 

From 402ef505fee84a3285dfb73bb723ccbf25fd46a1 Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Thu, 18 Aug 2016 00:36:18 +0300
Subject: [PATCH 04/11] Fix unixy compilation.

---
 mesonbuild/compilers.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index 744d75f8f6b9..8fd43de0e945 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -2343,3 +2343,6 @@ def unix_link_flags_to_native(self, args):
 
     def unix_compile_flags_to_native(self, args):
         return args[:]
+
+    def get_link_debugfile_args(self, targetfile):
+        return []

From 1bed33fba2c78c95d98795405085139e3e6abc45 Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Thu, 18 Aug 2016 22:56:14 +0300
Subject: [PATCH 05/11] Create pdbs that work when using pch or doing extract
 object (sadly not both).

---
 mesonbuild/backend/ninjabackend.py | 34 ++++++++++++++++++++++++++----
 mesonbuild/compilers.py            | 24 +++++++++++++--------
 2 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index a42db9fd5c65..94f90074bc72 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -1433,6 +1433,33 @@ def get_cross_stdlib_args(self, target, compiler):
             return []
         return compiler.get_no_stdinc_args()
 
+
+    def get_pdb_name_suffix(self, target):
+        if isinstance(target, build.Executable):
+            suffix = '__exe'
+        elif isinstance(target, build.SharedLibrary):
+            suffix = '__dll'
+        elif isinstance(target, build.StaticLibrary):
+            suffix = '__lib'
+        else:
+            raise MesonException('Tried to build PDB for a non-buildtarget. Please file a bug.')
+        return suffix
+
+
+    def get_compile_debugfile_args(self, compiler, target, objfile):
+        if compiler.id != 'msvc':
+            return []
+        suffix = self.get_pdb_name_suffix(target)
+        if target.has_pch():
+            tfilename = self.get_target_filename_abs(target)
+            return compiler.get_compile_debugfile_args(tfilename, suffix)
+        else:
+            return compiler.get_compile_debugfile_args(objfile, suffix)
+
+    def get_link_debugfile_args(self, linker, target, outname):
+        suffix = self.get_pdb_name_suffix(target)
+        return linker.get_link_debugfile_args(outname, suffix)
+
     def generate_single_compile(self, target, outfile, src, is_generated=False, header_deps=[], order_deps=[]):
         if(isinstance(src, str) and src.endswith('.h')):
             raise RuntimeError('Fug')
@@ -1522,7 +1549,7 @@ def generate_single_compile(self, target, outfile, src, is_generated=False, head
         if self.environment.coredata.base_options.get('b_pch', False):
             commands += self.get_pch_include_args(compiler, target)
 
-        commands += compiler.get_compile_debugfile_args(self.get_target_filename_abs(target))
+        commands += self.get_compile_debugfile_args(compiler, target, rel_obj)
         crstr = ''
         if target.is_cross:
             crstr = '_CROSS'
@@ -1591,8 +1618,7 @@ def generate_msvc_pch_command(self, target, compiler, pch):
         just_name = os.path.split(header)[1]
         (objname, pch_args) = compiler.gen_pch_args(just_name, source, dst)
         commands += pch_args
-        tfilename = self.get_target_filename_abs(target)
-        commands += compiler.get_compile_debugfile_args(tfilename)
+        commands += self.get_compile_debugfile_args(compiler, target, objname)
         dep = dst + '.' + compiler.get_depfile_suffix()
         return (commands, dep, dst, [objname])
 
@@ -1672,7 +1698,7 @@ def generate_link(self, target, outfile, outname, obj_list, linker, extra_args=[
                                                      linker)
         commands += linker.get_buildtype_linker_args(self.environment.coredata.get_builtin_option('buildtype'))
         commands += linker.get_option_link_args(self.environment.coredata.compiler_options)
-        commands += linker.get_link_debugfile_args(outname)
+        commands += self.get_link_debugfile_args(linker, target, outname)
         if not(isinstance(target, build.StaticLibrary)):
             commands += self.environment.coredata.external_link_args[linker.get_language()]
         if isinstance(target, build.Executable):
diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index 8fd43de0e945..4738abdaefc0 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -354,10 +354,10 @@ def get_colorout_args(self, colortype):
 
     # Some compilers (msvc) write debug info to a separate file.
     # These args specify where it should be written.
-    def get_compile_debugfile_args(self, rel_obj):
+    def get_compile_debugfile_args(self, rel_obj, fname_suffix):
         return []
 
-    def get_link_debugfile_args(self, rel_obj):
+    def get_link_debugfile_args(self, rel_obj, fname_suffix):
         return []
 
 class CCompiler(Compiler):
@@ -1607,12 +1607,16 @@ def has_argument(self, arg, env):
             raise MesonException('Compiling test app failed.')
         return not(warning_text in stde or warning_text in stdo)
 
-    def get_compile_debugfile_args(self, rel_obj):
-        pdbarr = rel_obj.split('.')[:-1] + ['pdb']
+    def get_compile_debugfile_args(self, rel_obj, name_suffix):
+        pdbarr = rel_obj.split('.')[:-1]
+        pdbarr[-1] += name_suffix
+        pdbarr += ['pdb']
         return ['/Fd' + '.'.join(pdbarr)]
 
-    def get_link_debugfile_args(self, targetfile):
-        pdbarr = targetfile.split('.')[:-1] + ['pdb']
+    def get_link_debugfile_args(self, targetfile, name_suffix):
+        pdbarr = targetfile.split('.')[:-1]
+        pdbarr[-1] += name_suffix
+        pdbarr += ['pdb']
         return ['/DEBUG', '/PDB:' + '.'.join(pdbarr)]
 
 class VisualStudioCPPCompiler(VisualStudioCCompiler):
@@ -2291,8 +2295,10 @@ def unix_link_flags_to_native(self, args):
     def unix_compile_flags_to_native(self, args):
         return args[:]
 
-    def get_link_debugfile_args(self, targetfile):
-        pdbarr = targetfile.split('.')[:-1] + ['pdb']
+    def get_link_debugfile_args(self, targetfile, name_suffix):
+        pdbarr = targetfile.split('.')[:-1]
+        pdbarr[-1] += name_suffix
+        pdbarr += ['pdb']
         return ['/DEBUG', '/PDB:' + '.'.join(pdbarr)]
 
 class ArLinker():
@@ -2344,5 +2350,5 @@ def unix_link_flags_to_native(self, args):
     def unix_compile_flags_to_native(self, args):
         return args[:]
 
-    def get_link_debugfile_args(self, targetfile):
+    def get_link_debugfile_args(self, targetfile, suffix):
         return []

From 36870ace0fb52ee8f2ca40c8ddb9cfb142032906 Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Thu, 18 Aug 2016 23:15:54 +0300
Subject: [PATCH 06/11] Document pdb insanity a bit.

---
 mesonbuild/backend/ninjabackend.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 94f90074bc72..7a9ad445edc6 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -1449,6 +1449,30 @@ def get_pdb_name_suffix(self, target):
     def get_compile_debugfile_args(self, compiler, target, objfile):
         if compiler.id != 'msvc':
             return []
+        # The way MSVC uses PDB files is documented exactly nowhere so
+        # the following is what we have been able to decipher via reverse
+        # engineering.
+        #
+        # Each object file gets the path of its PDB file written inside it.
+        # This can be either the final PDB (for, say, foo.exe) or an object
+        # pdb (for foo.obj). If the former, then each compilation step locks
+        # the pdb file for writing, which is a bottleneck and object files from
+        # one target can not be used in a different target. The latter seems
+        # to be the sensible one (and what Unix does) but there is a catch.
+        # If you try to use precompiled headers MSVC will error out because
+        # both source and pch pdbs go in the same file and they must be the same.
+        # This means:
+        #
+        # - pch files must be compiled anew for every object file (negating
+        #   the entire point of having them in the first place)
+        # - when using pch, output must go to the target pdb
+        #
+        # Since both of these are broken in some way, use the one that works
+        # for each target. This unfortunately means that you can't combine
+        # pch and object extraction in a single target.
+        #
+        # If you feel that the above is completely wrong and all of this is
+        # actually doable, please send patches.
         suffix = self.get_pdb_name_suffix(target)
         if target.has_pch():
             tfilename = self.get_target_filename_abs(target)

From a9da6c513281bd7c213d8d3d33c78c7ceed9dfd4 Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Fri, 2 Sep 2016 22:52:37 +0300
Subject: [PATCH 07/11] Moved targets with same name into subdirs to make all
 tests pass.

---
 mesonbuild/backend/ninjabackend.py            | 21 +++----------------
 mesonbuild/compilers.py                       | 15 ++++++-------
 .../common/86 same basename/meson.build       |  8 +++----
 .../86 same basename/sharedsub/meson.build    |  1 +
 .../86 same basename/staticsub/meson.build    |  3 +++
 5 files changed, 16 insertions(+), 32 deletions(-)
 create mode 100644 test cases/common/86 same basename/sharedsub/meson.build
 create mode 100644 test cases/common/86 same basename/staticsub/meson.build

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 7a9ad445edc6..1f848f3d6c57 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -1433,19 +1433,6 @@ def get_cross_stdlib_args(self, target, compiler):
             return []
         return compiler.get_no_stdinc_args()
 
-
-    def get_pdb_name_suffix(self, target):
-        if isinstance(target, build.Executable):
-            suffix = '__exe'
-        elif isinstance(target, build.SharedLibrary):
-            suffix = '__dll'
-        elif isinstance(target, build.StaticLibrary):
-            suffix = '__lib'
-        else:
-            raise MesonException('Tried to build PDB for a non-buildtarget. Please file a bug.')
-        return suffix
-
-
     def get_compile_debugfile_args(self, compiler, target, objfile):
         if compiler.id != 'msvc':
             return []
@@ -1473,16 +1460,14 @@ def get_compile_debugfile_args(self, compiler, target, objfile):
         #
         # If you feel that the above is completely wrong and all of this is
         # actually doable, please send patches.
-        suffix = self.get_pdb_name_suffix(target)
         if target.has_pch():
             tfilename = self.get_target_filename_abs(target)
-            return compiler.get_compile_debugfile_args(tfilename, suffix)
+            return compiler.get_compile_debugfile_args(tfilename)
         else:
-            return compiler.get_compile_debugfile_args(objfile, suffix)
+            return compiler.get_compile_debugfile_args(objfile)
 
     def get_link_debugfile_args(self, linker, target, outname):
-        suffix = self.get_pdb_name_suffix(target)
-        return linker.get_link_debugfile_args(outname, suffix)
+        return linker.get_link_debugfile_args(outname)
 
     def generate_single_compile(self, target, outfile, src, is_generated=False, header_deps=[], order_deps=[]):
         if(isinstance(src, str) and src.endswith('.h')):
diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index 4738abdaefc0..8394acad226e 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -354,10 +354,10 @@ def get_colorout_args(self, colortype):
 
     # Some compilers (msvc) write debug info to a separate file.
     # These args specify where it should be written.
-    def get_compile_debugfile_args(self, rel_obj, fname_suffix):
+    def get_compile_debugfile_args(self, rel_obj):
         return []
 
-    def get_link_debugfile_args(self, rel_obj, fname_suffix):
+    def get_link_debugfile_args(self, rel_obj):
         return []
 
 class CCompiler(Compiler):
@@ -1607,15 +1607,13 @@ def has_argument(self, arg, env):
             raise MesonException('Compiling test app failed.')
         return not(warning_text in stde or warning_text in stdo)
 
-    def get_compile_debugfile_args(self, rel_obj, name_suffix):
+    def get_compile_debugfile_args(self, rel_obj):
         pdbarr = rel_obj.split('.')[:-1]
-        pdbarr[-1] += name_suffix
         pdbarr += ['pdb']
         return ['/Fd' + '.'.join(pdbarr)]
 
-    def get_link_debugfile_args(self, targetfile, name_suffix):
+    def get_link_debugfile_args(self, targetfile):
         pdbarr = targetfile.split('.')[:-1]
-        pdbarr[-1] += name_suffix
         pdbarr += ['pdb']
         return ['/DEBUG', '/PDB:' + '.'.join(pdbarr)]
 
@@ -2295,9 +2293,8 @@ def unix_link_flags_to_native(self, args):
     def unix_compile_flags_to_native(self, args):
         return args[:]
 
-    def get_link_debugfile_args(self, targetfile, name_suffix):
+    def get_link_debugfile_args(self, targetfile):
         pdbarr = targetfile.split('.')[:-1]
-        pdbarr[-1] += name_suffix
         pdbarr += ['pdb']
         return ['/DEBUG', '/PDB:' + '.'.join(pdbarr)]
 
@@ -2350,5 +2347,5 @@ def unix_link_flags_to_native(self, args):
     def unix_compile_flags_to_native(self, args):
         return args[:]
 
-    def get_link_debugfile_args(self, targetfile, suffix):
+    def get_link_debugfile_args(self, targetfile):
         return []
diff --git a/test cases/common/86 same basename/meson.build b/test cases/common/86 same basename/meson.build
index 3dc384ee7371..856c536c00a9 100644
--- a/test cases/common/86 same basename/meson.build	
+++ b/test cases/common/86 same basename/meson.build	
@@ -1,13 +1,11 @@
 project('same basename', 'c')
 
+subdir('sharedsub')
+subdir('staticsub')
+
 # Use the same source file to check that each top level target
 # has its own unique working directory. If they don't
 # then the .o files will clobber each other.
-shlib = shared_library('name', 'lib.c', c_args : '-DSHAR')
-
-# On Windows a static lib is now libfoo.a, so it does not conflict with foo.lib
-# from the shared library above
-stlib = static_library('name', 'lib.c', c_args : '-DSTAT')
 
 exe1 = executable('name', 'exe1.c', link_with : stlib)
 exe2 = executable('name2', 'exe2.c', link_with : shlib)
diff --git a/test cases/common/86 same basename/sharedsub/meson.build b/test cases/common/86 same basename/sharedsub/meson.build
new file mode 100644
index 000000000000..29654a94dcab
--- /dev/null
+++ b/test cases/common/86 same basename/sharedsub/meson.build	
@@ -0,0 +1 @@
+shlib = shared_library('name', '../lib.c', c_args : '-DSHAR')
diff --git a/test cases/common/86 same basename/staticsub/meson.build b/test cases/common/86 same basename/staticsub/meson.build
new file mode 100644
index 000000000000..5e5242e06d58
--- /dev/null
+++ b/test cases/common/86 same basename/staticsub/meson.build	
@@ -0,0 +1,3 @@
+# On Windows a static lib is now libfoo.a, so it does not conflict with foo.lib
+# from the shared library above
+stlib = static_library('name', '../lib.c', c_args : '-DSTAT')

From c7e5e558f9b80c695907336f2150d097d9883ba4 Mon Sep 17 00:00:00 2001
From: Jussi Pakkanen <jpakkane@gmail.com>
Date: Sat, 10 Sep 2016 13:11:13 +0300
Subject: [PATCH 08/11] More PDB explanation.

---
 mesonbuild/backend/ninjabackend.py | 54 +++++++++++++++++++++---------
 1 file changed, 39 insertions(+), 15 deletions(-)

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 1f848f3d6c57..28667b7953d8 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -1437,29 +1437,53 @@ def get_compile_debugfile_args(self, compiler, target, objfile):
         if compiler.id != 'msvc':
             return []
         # The way MSVC uses PDB files is documented exactly nowhere so
-        # the following is what we have been able to decipher via reverse
-        # engineering.
+        # the following is what we have been able to decipher via
+        # reverse engineering.
+        #
+        # Each object file gets the path of its PDB file written
+        # inside it.  This can be either the final PDB (for, say,
+        # foo.exe) or an object pdb (for foo.obj). If the former, then
+        # each compilation step locks the pdb file for writing, which
+        # is a bottleneck and object files from one target can not be
+        # used in a different target. The latter seems to be the
+        # sensible one (and what Unix does) but there is a catch.  If
+        # you try to use precompiled headers MSVC will error out
+        # because both source and pch pdbs go in the same file and
+        # they must be the same.
         #
-        # Each object file gets the path of its PDB file written inside it.
-        # This can be either the final PDB (for, say, foo.exe) or an object
-        # pdb (for foo.obj). If the former, then each compilation step locks
-        # the pdb file for writing, which is a bottleneck and object files from
-        # one target can not be used in a different target. The latter seems
-        # to be the sensible one (and what Unix does) but there is a catch.
-        # If you try to use precompiled headers MSVC will error out because
-        # both source and pch pdbs go in the same file and they must be the same.
         # This means:
         #
         # - pch files must be compiled anew for every object file (negating
         #   the entire point of having them in the first place)
         # - when using pch, output must go to the target pdb
         #
-        # Since both of these are broken in some way, use the one that works
-        # for each target. This unfortunately means that you can't combine
-        # pch and object extraction in a single target.
+        # Since both of these are broken in some way, use the one that
+        # works for each target. This unfortunately means that you
+        # can't combine pch and object extraction in a single target.
+        #
+        # PDB files also lead to filename collisions. A target foo.exe
+        # has a corresponding foo.pdb. A shared library foo.dll _also_
+        # has pdb file called foo.pdb. So will a static library
+        # foo.lib, which clobbers both foo.pdb _and_ the dll file's
+        # export library called foo.lib (by default, currently we name
+        # them libfoo.a to avoidt this issue). You can give the files
+        # unique names such as foo_exe.pdb but VC also generates a
+        # bunch of other files which take their names from the target
+        # basename (i.e. "foo") and stomp on each other.
         #
-        # If you feel that the above is completely wrong and all of this is
-        # actually doable, please send patches.
+        # CMake solves this problem by doing two things. First of all
+        # static libraries do not generate pdb files at
+        # all. Presumably you don't need them and VC is smart enough
+        # to look up the original data when linking (speculation, not
+        # tested). The second solution is that you can only have
+        # target named "foo" as an exe, shared lib _or_ static
+        # lib. This makes filename collisions not happen. The downside
+        # is that you can't have an executable foo that uses a shared
+        # library libfoo.so, which is a common idiom on Unix.
+        #
+        # If you feel that the above is completely wrong and all of
+        # this is actually doable, please send patches.
+
         if target.has_pch():
             tfilename = self.get_target_filename_abs(target)
             return compiler.get_compile_debugfile_args(tfilename)

From 4228a6dab6c591298b0895ce6a1ee034ba874581 Mon Sep 17 00:00:00 2001
From: Nirbheek Chauhan <nirbheek@centricular.com>
Date: Sat, 10 Sep 2016 21:39:22 +0530
Subject: [PATCH 09/11] vs: Never serialize debug file generation with /FS

/FS forces .pdb file writing to be serialized through MSPDBSRV.EXE,
which is supposed to solve concurrency issues (esp. with anti-viruses),
but it doesn't actually always work. It also isn't needed anymore since
we don't use a shared vcXXX.pdb temporary file for pdb writing and use
/Fd to explicitly set a per-target pdb filename instead.

Not serializing the PDB writing will make a large difference on fast
disks when linking multiple libraries and executables simultaneously.
---
 mesonbuild/compilers.py | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index 8394acad226e..73f2416f8776 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -1436,16 +1436,11 @@ def can_compile(self, filename):
 class VisualStudioCCompiler(CCompiler):
     std_warn_args = ['/W3']
     std_opt_args= ['/O2']
-    vs2010_always_args = ['/nologo', '/showIncludes']
-    vs2013_always_args = ['/nologo', '/showIncludes', '/FS']
 
     def __init__(self, exelist, version, is_cross, exe_wrap):
         CCompiler.__init__(self, exelist, version, is_cross, exe_wrap)
         self.id = 'msvc'
-        if int(version.split('.')[0]) > 17:
-            self.always_args = VisualStudioCCompiler.vs2013_always_args
-        else:
-            self.always_args = VisualStudioCCompiler.vs2010_always_args
+        self.always_args = ['/nologo', '/showIncludes']
         self.warn_args = {'1': ['/W2'],
                           '2': ['/W3'],
                           '3': ['/w4']}

From 0840a908f235ac3a4df271e2cd262cad0cfc5cbd Mon Sep 17 00:00:00 2001
From: Nirbheek Chauhan <nirbheek@centricular.com>
Date: Mon, 9 May 2016 17:11:45 +0530
Subject: [PATCH 10/11] ninjabackend: Add support for installing .pdb files

.pdb files are files created by MSVC which have debug symbols. These are
created when /ZI or /Zi is passed to the compiler and /DEBUG to the
linker.
---
 mesonbuild/backend/backends.py     |  6 +++++
 mesonbuild/backend/ninjabackend.py |  7 ++++++
 mesonbuild/build.py                | 37 ++++++++++++++++++++++++++++++
 3 files changed, 50 insertions(+)

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 1f1c3ca01a47..81283dc80972 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -118,6 +118,12 @@ def get_target_filename_for_linking(self, target):
             return os.path.join(self.get_target_dir(target), target.get_filename())
         raise AssertionError('BUG: Tried to link to something that\'s not a library')
 
+    def get_target_debug_filename(self, target):
+        fname = target.get_debug_filename()
+        if not fname:
+            raise AssertionError("BUG: Tried to generate debug filename when it doesn't exist")
+        return os.path.join(self.get_target_dir(target), fname)
+
     def get_target_dir(self, target):
         if self.environment.coredata.get_builtin_option('layout') == 'mirror':
             dirname = target.get_subdir()
diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 28667b7953d8..e00fe2f8f8c8 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -523,6 +523,13 @@ def generate_target_install(self, d):
                 else:
                     # XXX: Add BuildTarget-specific install dir cases here
                     outdir = self.environment.get_libdir()
+                if isinstance(t, build.SharedLibrary) or isinstance(t, build.Executable):
+                    if t.get_debug_filename():
+                        # Install the debug symbols file in the same place as
+                        # the target itself. It has no aliases, should not be
+                        # stripped, and doesn't have an install_rpath
+                        i = [self.get_target_debug_filename(t), outdir, [], False, '']
+                        d.targets.append(i)
                 i = [self.get_target_filename(t), outdir, t.get_aliaslist(),\
                     should_strip, t.install_rpath]
                 d.targets.append(i)
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 61dace7c153e..6dd2bde532b2 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -205,6 +205,8 @@ def __init__(self, name, subdir, subproject, is_cross, sources, objects, environ
         self.link_targets = []
         self.link_depends = []
         self.filename = 'no_name'
+        # The file with debugging symbols
+        self.debug_filename = None
         self.need_install = False
         self.pch = {}
         self.extra_args = {}
@@ -466,6 +468,15 @@ def get_subdir(self):
     def get_filename(self):
         return self.filename
 
+    def get_debug_filename(self):
+        """
+        The name of the file that contains debugging symbols for this target
+
+        Returns None if there are no debugging symbols or if they are embedded
+        in the filename itself
+        """
+        return self.debug_filename
+
     def get_extra_args(self, language):
         return self.extra_args.get(language, [])
 
@@ -708,6 +719,11 @@ def __init__(self, name, subdir, subproject, is_cross, sources, objects, environ
         self.filename = self.name
         if self.suffix:
             self.filename += '.' + self.suffix
+        # See determine_debug_filenames() in build.SharedLibrary
+        buildtype = environment.coredata.get_builtin_option('buildtype')
+        if compiler_is_msvc(self.sources, is_cross, environment) and \
+           buildtype.startswith('debug'):
+            self.debug_filename = self.prefix + self.name + '.pdb'
 
     def type_suffix(self):
         return "@exe"
@@ -733,6 +749,11 @@ def __init__(self, name, subdir, subproject, is_cross, sources, objects, environ
             else:
                 self.suffix = 'a'
         self.filename = self.prefix + self.name + '.' + self.suffix
+        # See determine_debug_filenames() in build.SharedLibrary
+        buildtype = environment.coredata.get_builtin_option('buildtype')
+        if compiler_is_msvc(self.sources, is_cross, environment) and \
+           buildtype.startswith('debug'):
+            self.debug_filename = self.prefix + self.name + '.pdb'
 
     def type_suffix(self):
         return "@sta"
@@ -755,6 +776,7 @@ def __init__(self, name, subdir, subproject, is_cross, sources, objects, environ
             self.suffix = None
         self.basic_filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
         self.determine_filenames(is_cross, environment)
+        self.determine_debug_filenames(is_cross, environment)
 
     def determine_filenames(self, is_cross, env):
         """
@@ -846,6 +868,21 @@ def determine_filenames(self, is_cross, env):
             self.suffix = suffix
         self.filename = self.filename_tpl.format(self)
 
+    def determine_debug_filenames(self, is_cross, env):
+        """
+        Determine the debug filename(s) using the prefix/name/etc detected in
+        determine_filenames() above.
+        """
+        buildtype = env.coredata.get_builtin_option('buildtype')
+        if compiler_is_msvc(self.sources, is_cross, env) and buildtype.startswith('debug'):
+            # Currently we only implement separate debug symbol files for MSVC
+            # since the toolchain does it for us. Other toolchains embed the
+            # debugging symbols in the file itself by default.
+            if self.soversion:
+                self.debug_filename = '{0.prefix}{0.name}-{0.soversion}.pdb'.format(self)
+            else:
+                self.debug_filename = '{0.prefix}{0.name}.pdb'.format(self)
+
     def process_kwargs(self, kwargs, environment):
         super().process_kwargs(kwargs, environment)
         # Shared library version

From 91c5f07a8efe550c4b64c72d0914108239fcc1c6 Mon Sep 17 00:00:00 2001
From: Nirbheek Chauhan <nirbheek@centricular.com>
Date: Fri, 24 Jun 2016 10:47:18 +0530
Subject: [PATCH 11/11] run_tests.py: Ignore .pdb files while validating
 install

Their presence depends on build options and compiler, and we don't
currently have the test infrastructure to deal with this.
---
 run_tests.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/run_tests.py b/run_tests.py
index 34258d8cd996..b71ab6d69af0 100755
--- a/run_tests.py
+++ b/run_tests.py
@@ -168,7 +168,7 @@ def validate_install(srcdir, installdir):
     # Check if there are any unexpected files
     found = get_relative_files_list_from_dir(installdir)
     for fname in found:
-        if fname not in expected:
+        if fname not in expected and not fname.endswith('.pdb'):
             ret_msg += 'Extra file {0} found.\n'.format(fname)
     return ret_msg