diff options
Diffstat (limited to 'clang')
| -rw-r--r-- | clang/lib/CodeGen/CGStmt.cpp | 26 | ||||
| -rw-r--r-- | clang/test/CodeGen/asm-attrs.c | 33 |
2 files changed, 58 insertions, 1 deletions
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp index a12f29534bf..7a0b8a35be0 100644 --- a/clang/lib/CodeGen/CGStmt.cpp +++ b/clang/lib/CodeGen/CGStmt.cpp @@ -1852,6 +1852,14 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { std::vector<llvm::Value*> InOutArgs; std::vector<llvm::Type*> InOutArgTypes; + // An inline asm can be marked readonly if it meets the following conditions: + // - it doesn't have any sideeffects + // - it doesn't clobber memory + // - it doesn't return a value by-reference + // It can be marked readnone if it doesn't have any input memory constraints + // in addition to meeting the conditions listed above. + bool ReadOnly = true, ReadNone = true; + for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) { TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i]; @@ -1915,6 +1923,7 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { Args.push_back(Dest.getAddress()); Constraints += "=*"; Constraints += OutputConstraint; + ReadOnly = ReadNone = false; } if (Info.isReadWrite()) { @@ -1959,6 +1968,9 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; + if (Info.allowsMemory()) + ReadNone = false; + if (!Constraints.empty()) Constraints += ','; @@ -2023,7 +2035,9 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) { StringRef Clobber = S.getClobber(i); - if (Clobber != "memory" && Clobber != "cc") + if (Clobber == "memory") + ReadOnly = ReadNone = false; + else if (Clobber != "cc") Clobber = getTarget().getNormalizedGCCRegisterName(Clobber); if (!Constraints.empty()) @@ -2063,6 +2077,16 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { Result->addAttribute(llvm::AttributeSet::FunctionIndex, llvm::Attribute::NoUnwind); + // Attach readnone and readonly attributes. + if (!HasSideEffect) { + if (ReadNone) + Result->addAttribute(llvm::AttributeSet::FunctionIndex, + llvm::Attribute::ReadNone); + else if (ReadOnly) + Result->addAttribute(llvm::AttributeSet::FunctionIndex, + llvm::Attribute::ReadOnly); + } + // Slap the source location of the inline asm into a !srcloc metadata on the // call. if (const GCCAsmStmt *gccAsmStmt = dyn_cast<GCCAsmStmt>(&S)) { diff --git a/clang/test/CodeGen/asm-attrs.c b/clang/test/CodeGen/asm-attrs.c new file mode 100644 index 00000000000..ae7287953e0 --- /dev/null +++ b/clang/test/CodeGen/asm-attrs.c @@ -0,0 +1,33 @@ +// RUN: %clang_cc1 -triple armv7-apple-darwin -emit-llvm %s -o - | FileCheck %s + +// CHECK: call i32 asm "foo0", {{.*}} [[READNONE:#[0-9]+]] +// CHECK: call i32 asm "foo1", {{.*}} [[READNONE]] +// CHECK: call i32 asm "foo2", {{.*}} [[NOATTRS:#[0-9]+]] +// CHECK: call i32 asm sideeffect "foo3", {{.*}} [[NOATTRS]] +// CHECK: call i32 asm "foo4", {{.*}} [[READONLY:#[0-9]+]] +// CHECK: call i32 asm "foo5", {{.*}} [[READONLY]] +// CHECK: call i32 asm "foo6", {{.*}} [[NOATTRS]] +// CHECK: call void asm sideeffect "foo7", {{.*}} [[NOATTRS]] +// CHECK: call void asm "foo8", {{.*}} [[NOATTRS]] + +// CHECK: attributes [[READNONE]] = { nounwind readnone } +// CHECK: attributes [[NOATTRS]] = { nounwind } +// CHECK: attributes [[READONLY]] = { nounwind readonly } + +int g0, g1; + +struct S { + int i; +} g2; + +void test_attrs(int a) { + __asm__ ("foo0" : "=r"(g1) : "r"(a)); + __asm__ ("foo1" : "=r"(g1) : "r"(a) : "cc"); + __asm__ ("foo2" : "=r"(g1) : "r"(a) : "memory"); + __asm__ volatile("foo3" : "=r"(g1) : "r"(a)); + __asm__ ("foo4" : "=r"(g1) : "r"(a), "m"(g0)); + __asm__ ("foo5" : "=r"(g1) : "r"(a), "Q"(g0)); + __asm__ ("foo6" : "=r"(g1), "=m"(g0) : "r"(a)); + __asm__ ("foo7" : : "r"(a)); + __asm__ ("foo8" : "=r"(g2) : "r"(a)); +} |
