[mips] The default ABI depends on the CPU not the Arch on MTI and IMG vendor triples.

Summary:
32-bit CPU's default to O32. 64-bit CPU's default to N64. The default CPU
(mips32r2/mips64r2) still depends on the arch so there's no functional
change when the CPU isn't specified but commands like:
  clang -target mips-mti-linux-gnu -mips64r2
will now default to a 64-bit ABI like our gcc toolchains do* instead of
asserting in the backend**.

Other vendors (including Triple::UnknownVendor) still derive the default
ABI from the arch.

* Although not the same one as our gcc toolchains, clang has historically
  defaulted to N64 where gcc defaults to N32.
** Mixing O32 and a 64-bit CPU causing assertions is a long-standing bug.

Reviewers: atanasyan

Subscribers: sdardis, cfe-commits

Differential Revision: http://reviews.llvm.org/D21016

llvm-svn: 271884

1 files changed, 24 insertions, 0 deletions

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 8a5083d1..fbf1e3b 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -1221,6 +1221,30 @@ void mips::getMipsCPUAndABI(const ArgList &Args, const llvm::Triple &Triple,
     }
   }
 
+  if (ABIName.empty() &&
+      (Triple.getVendor() == llvm::Triple::MipsTechnologies ||
+       Triple.getVendor() == llvm::Triple::ImaginationTechnologies)) {
+    ABIName = llvm::StringSwitch<const char *>(CPUName)
+                  .Case("mips1", "o32")
+                  .Case("mips2", "o32")
+                  .Case("mips3", "n64")
+                  .Case("mips4", "n64")
+                  .Case("mips5", "n64")
+                  .Case("mips32", "o32")
+                  .Case("mips32r2", "o32")
+                  .Case("mips32r3", "o32")
+                  .Case("mips32r5", "o32")
+                  .Case("mips32r6", "o32")
+                  .Case("mips64", "n64")
+                  .Case("mips64r2", "n64")
+                  .Case("mips64r3", "n64")
+                  .Case("mips64r5", "n64")
+                  .Case("mips64r6", "n64")
+                  .Case("octeon", "n64")
+                  .Case("p5600", "o32")
+                  .Default("");
+  }
+
   if (ABIName.empty()) {
     // Deduce ABI name from the target triple.
     if (Triple.getArch() == llvm::Triple::mips ||