Misc typos fixes in ./lib folder

Summary: Found via `codespell -q 3 -I ../clang-whitelist.txt -L uint,importd,crasher,gonna,cant,ue,ons,orign,ned`

Reviewers: teemperor

Reviewed By: teemperor

Subscribers: teemperor, jholewinski, jvesely, nhaehnle, whisperity, jfb, cfe-commits

Differential Revision: https://reviews.llvm.org/D55475

llvm-svn: 348755
diff --git a/clang/lib/Driver/ToolChains/AMDGPU.cpp b/clang/lib/Driver/ToolChains/AMDGPU.cpp
index 451f31d..a421a09 100644
--- a/clang/lib/Driver/ToolChains/AMDGPU.cpp
+++ b/clang/lib/Driver/ToolChains/AMDGPU.cpp
@@ -104,7 +104,7 @@
     llvm::opt::ArgStringList &CC1Args,
     Action::OffloadKind DeviceOffloadingKind) const {
   // Default to "hidden" visibility, as object level linking will not be
-  // supported for the forseeable future.
+  // supported for the foreseeable future.
   if (!DriverArgs.hasArg(options::OPT_fvisibility_EQ,
                          options::OPT_fvisibility_ms_compat)) {
     CC1Args.push_back("-fvisibility");
diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 4a341e8..e5dafa2 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -98,7 +98,7 @@
     SourceAction = SourceAction->getInputs()[0];
   }
 
-  // If -fno-integrated-as is used add -Q to the darwin assember driver to make
+  // If -fno-integrated-as is used add -Q to the darwin assembler driver to make
   // sure it runs its system assembler not clang's integrated assembler.
   // Applicable to darwin11+ and Xcode 4+.  darwin<10 lacked integrated-as.
   // FIXME: at run-time detect assembler capabilities or rely on version
diff --git a/clang/lib/Driver/ToolChains/Hexagon.cpp b/clang/lib/Driver/ToolChains/Hexagon.cpp
index 68eea27..d302a3e 100644
--- a/clang/lib/Driver/ToolChains/Hexagon.cpp
+++ b/clang/lib/Driver/ToolChains/Hexagon.cpp
@@ -76,7 +76,7 @@
 
   // Handle -mhvx-length=.
   if (Arg *A = Args.getLastArg(options::OPT_mhexagon_hvx_length_EQ)) {
-    // These falgs are valid only if HVX in enabled.
+    // These flags are valid only if HVX in enabled.
     if (!HasHVX)
       D.Diag(diag::err_drv_invalid_hvx_length);
     else if (A->getOption().matches(options::OPT_mhexagon_hvx_length_EQ))