[OpenCL] Makes kernels use the SPIR_KERNEL CC by default.

Rationale: OpenCL kernels are called via an explicit runtime API
with arguments set with clSetKernelArg(), not as normal sub-functions.
Return SPIR_KERNEL by default as the kernel calling convention to ensure
the fingerprint is fixed such way that each OpenCL argument gets one
matching argument in the produced kernel function argument list to enable
feasible implementation of clSetKernelArg() with aggregates etc. In case
we would use the default C calling conv here, clSetKernelArg() might
break depending on the target-specific conventions; different targets
might split structs passed as values to multiple function arguments etc.

https://reviews.llvm.org/D33639

llvm-svn: 304389

1 files changed, 16 insertions, 0 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 6be83d22a25..605f73802af 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -3123,6 +3123,7 @@ public:
     case CC_Swift:
     case CC_X86Pascal:
     case CC_IntelOclBicc:
+    case CC_OpenCLKernel:
       return CCCR_OK;
     default:
       return CCCR_Warning;
@@ -4834,6 +4835,7 @@ public:
     case CC_PreserveMost:
     case CC_PreserveAll:
     case CC_X86RegCall:
+    case CC_OpenCLKernel:
       return CCCR_OK;
     default:
       return CCCR_Warning;
@@ -4907,6 +4909,7 @@ public:
     case CC_X86_64SysV:
     case CC_Swift:
     case CC_X86RegCall:
+    case CC_OpenCLKernel:
       return CCCR_OK;
     default:
       return CCCR_Warning;
@@ -5860,6 +5863,7 @@ public:
     case CC_AAPCS:
     case CC_AAPCS_VFP:
     case CC_Swift:
+    case CC_OpenCLKernel:
       return CCCR_OK;
     default:
       return CCCR_Warning;
@@ -6019,6 +6023,7 @@ public:
     case CC_X86VectorCall:
       return CCCR_Ignore;
     case CC_C:
+    case CC_OpenCLKernel:
       return CCCR_OK;
     default:
       return CCCR_Warning;
@@ -6329,6 +6334,7 @@ public:
     case CC_Swift:
     case CC_PreserveMost:
     case CC_PreserveAll:
+    case CC_OpenCLKernel:
       return CCCR_OK;
     default:
       return CCCR_Warning;
@@ -7380,6 +7386,7 @@ public:
     switch (CC) {
     case CC_C:
     case CC_Swift:
+    case CC_OpenCLKernel:
       return CCCR_OK;
     default:
       return CCCR_Warning;
@@ -7663,6 +7670,15 @@ public:
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
     return None;
   }
+  CallingConvCheckResult checkCallingConvention(CallingConv CC) const override {
+    switch (CC) {
+      default:
+        return CCCR_Warning;
+      case CC_C:
+      case CC_OpenCLKernel:
+        return CCCR_OK;
+    }
+  }
 };
 
 class MipsTargetInfo : public TargetInfo {