[clang] b915aec - Add method to TargetInfo to get CPU cache line size
via cfe-commits
cfe-commits at lists.llvm.org
Wed Mar 25 09:51:00 PDT 2020
Author: zoecarver
Date: 2020-03-25T09:50:38-07:00
New Revision: b915aec6b591bdd9a9ffef73db241353b5ba2e2c
URL: https://github.com/llvm/llvm-project/commit/b915aec6b591bdd9a9ffef73db241353b5ba2e2c
DIFF: https://github.com/llvm/llvm-project/commit/b915aec6b591bdd9a9ffef73db241353b5ba2e2c.diff
LOG: Add method to TargetInfo to get CPU cache line size
Summary:
This patch adds a virtual method `getCPUCacheLineSize()` to `TargetInfo`. Currently, I've only implemented the method in `X86TargetInfo`. It's extremely important that each CPU's cache line size correct (e.g., we can't just define it as `64` across the board) so, it has been a little slow getting to this point.
I'll work on the ARM CPUs next, but that will probably come later in a different patch.
Tags: #clang
Differential Revision: https://reviews.llvm.org/D74918
Added:
Modified:
clang/include/clang/Basic/TargetInfo.h
clang/lib/Basic/Targets/X86.cpp
clang/lib/Basic/Targets/X86.h
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
index cbfcece1b666..615f09985132 100644
--- a/clang/include/clang/Basic/TargetInfo.h
+++ b/clang/include/clang/Basic/TargetInfo.h
@@ -1206,6 +1206,10 @@ class TargetInfo : public virtual TransferrableTargetInfo,
"cpu_specific Multiversioning not implemented on this target");
}
+ // Get the cache line size of a given cpu. This method switches over
+ // the given cpu and returns "None" if the CPU is not found.
+ virtual Optional<unsigned> getCPUCacheLineSize() const { return None; }
+
// Returns maximal number of args passed in registers.
unsigned getRegParmMax() const {
assert(RegParmMax < 7 && "RegParmMax value is larger than AST can handle");
diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 7b575f52bb22..f35b520de657 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -1731,6 +1731,119 @@ bool X86TargetInfo::validateAsmConstraint(
}
}
+// Below is based on the following information:
+// +------------------------------------+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
+// | Processor Name | Cache Line Size (Bytes) | Source |
+// +------------------------------------+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
+// | i386 | 64 | https://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-optimization-manual.pdf |
+// | i486 | 16 | "four doublewords" (doubleword = 32 bits, 4 bits * 32 bits = 16 bytes) https://en.wikichip.org/w/images/d/d3/i486_MICROPROCESSOR_HARDWARE_REFERENCE_MANUAL_%281990%29.pdf and http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.126.4216&rep=rep1&type=pdf (page 29) |
+// | i586/Pentium MMX | 32 | https://www.7-cpu.com/cpu/P-MMX.html |
+// | i686/Pentium | 32 | https://www.7-cpu.com/cpu/P6.html |
+// | Netburst/Pentium4 | 64 | https://www.7-cpu.com/cpu/P4-180.html |
+// | Atom | 64 | https://www.7-cpu.com/cpu/Atom.html |
+// | Westmere | 64 | https://en.wikichip.org/wiki/intel/microarchitectures/sandy_bridge_(client) "Cache Architecture" |
+// | Sandy Bridge | 64 | https://en.wikipedia.org/wiki/Sandy_Bridge and https://www.7-cpu.com/cpu/SandyBridge.html |
+// | Ivy Bridge | 64 | https://blog.stuffedcow.net/2013/01/ivb-cache-replacement/ and https://www.7-cpu.com/cpu/IvyBridge.html |
+// | Haswell | 64 | https://www.7-cpu.com/cpu/Haswell.html |
+// | Boadwell | 64 | https://www.7-cpu.com/cpu/Broadwell.html |
+// | Skylake (including skylake-avx512) | 64 | https://www.nas.nasa.gov/hecc/support/kb/skylake-processors_550.html "Cache Hierarchy" |
+// | Cascade Lake | 64 | https://www.nas.nasa.gov/hecc/support/kb/cascade-lake-processors_579.html "Cache Hierarchy" |
+// | Skylake | 64 | https://en.wikichip.org/wiki/intel/microarchitectures/kaby_lake "Memory Hierarchy" |
+// | Ice Lake | 64 | https://www.7-cpu.com/cpu/Ice_Lake.html |
+// | Knights Landing | 64 | https://software.intel.com/en-us/articles/intel-xeon-phi-processor-7200-family-memory-management-optimizations "The Intel® Xeon Phi™ Processor Architecture" |
+// | Knights Mill | 64 | https://software.intel.com/sites/default/files/managed/9e/bc/64-ia-32-architectures-optimization-manual.pdf?countrylabel=Colombia "2.5.5.2 L1 DCache " |
+// +------------------------------------+-------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------+
+Optional<unsigned> X86TargetInfo::getCPUCacheLineSize() const {
+ switch (CPU) {
+ // i386
+ case CK_i386:
+ // i486
+ case CK_i486:
+ case CK_WinChipC6:
+ case CK_WinChip2:
+ case CK_C3:
+ // Lakemont
+ case CK_Lakemont:
+ return 16;
+
+ // i586
+ case CK_i586:
+ case CK_Pentium:
+ case CK_PentiumMMX:
+ // i686
+ case CK_PentiumPro:
+ case CK_i686:
+ case CK_Pentium2:
+ case CK_Pentium3:
+ case CK_PentiumM:
+ case CK_C3_2:
+ // K6
+ case CK_K6:
+ case CK_K6_2:
+ case CK_K6_3:
+ // Geode
+ case CK_Geode:
+ return 32;
+
+ // Netburst
+ case CK_Pentium4:
+ case CK_Prescott:
+ case CK_Nocona:
+ // Atom
+ case CK_Bonnell:
+ case CK_Silvermont:
+ case CK_Goldmont:
+ case CK_GoldmontPlus:
+ case CK_Tremont:
+
+ case CK_Westmere:
+ case CK_SandyBridge:
+ case CK_IvyBridge:
+ case CK_Haswell:
+ case CK_Broadwell:
+ case CK_SkylakeClient:
+ case CK_SkylakeServer:
+ case CK_Cascadelake:
+ case CK_Nehalem:
+ case CK_Cooperlake:
+ case CK_Cannonlake:
+ case CK_Tigerlake:
+ case CK_IcelakeClient:
+ case CK_IcelakeServer:
+ case CK_KNL:
+ case CK_KNM:
+ // K7
+ case CK_Athlon:
+ case CK_AthlonXP:
+ // K8
+ case CK_K8:
+ case CK_K8SSE3:
+ case CK_AMDFAM10:
+ // Bobcat
+ case CK_BTVER1:
+ case CK_BTVER2:
+ // Bulldozer
+ case CK_BDVER1:
+ case CK_BDVER2:
+ case CK_BDVER3:
+ case CK_BDVER4:
+ // Zen
+ case CK_ZNVER1:
+ case CK_ZNVER2:
+ // Deprecated
+ case CK_x86_64:
+ case CK_Yonah:
+ case CK_Penryn:
+ case CK_Core2:
+ return 64;
+
+ // The following currently have unknown cache line sizes (but they are probably all 64):
+ // Core
+ case CK_Generic:
+ return None;
+ }
+}
+
bool X86TargetInfo::validateOutputSize(const llvm::StringMap<bool> &FeatureMap,
StringRef Constraint,
unsigned Size) const {
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 5141caa6fb5b..0e0dae7db3ac 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -182,6 +182,8 @@ class LLVM_LIBRARY_VISIBILITY X86TargetInfo : public TargetInfo {
StringRef Name,
llvm::SmallVectorImpl<StringRef> &Features) const override;
+ Optional<unsigned> getCPUCacheLineSize() const override;
+
bool validateAsmConstraint(const char *&Name,
TargetInfo::ConstraintInfo &info) const override;
More information about the cfe-commits
mailing list