From f79a58ed62c4f0a595468737e4f72dd9ae7abbf7 Mon Sep 17 00:00:00 2001
From: Yochai Shefi Simchon <joch@graphtech.co.il>
Date: Wed, 10 Aug 2011 15:04:27 +0300
Subject: [PATCH] opengles emulator: fix shader parser precision qualifiers

Workaround to intel/linux driver issue.

Desktop OpenGL does not support precision qulifiers in shaders,
so we remove them by defining "precision" "mediump" "lowp" and
"highp" to blank.
That translates the line "precision mediump float;" to "float;" which
is a valid command according to the GLSL spec however it fails
to compile using the intel/linux driver.

This change adds a parser which removes completely the
precision command from the shader source.

Change-Id: I29a16bb78ac0000d624aa2f83e93ef5c6ad60345
---
 .../libs/Translator/GLES_V2/GLESv2Imp.cpp     |  11 +-
 .../libs/Translator/GLES_V2/ShaderParser.cpp  | 118 +++++++++++++++++-
 .../libs/Translator/GLES_V2/ShaderParser.h    |   2 +
 3 files changed, 125 insertions(+), 6 deletions(-)

diff --git a/tools/emulator/opengl/host/libs/Translator/GLES_V2/GLESv2Imp.cpp b/tools/emulator/opengl/host/libs/Translator/GLES_V2/GLESv2Imp.cpp
index c81b3462b..d768dd4a2 100644
--- a/tools/emulator/opengl/host/libs/Translator/GLES_V2/GLESv2Imp.cpp
+++ b/tools/emulator/opengl/host/libs/Translator/GLES_V2/GLESv2Imp.cpp
@@ -1296,11 +1296,16 @@ GL_APICALL void  GL_APIENTRY glGetShaderSource(GLuint shader, GLsizei bufsize, G
        SET_ERROR_IF(!objData.Ptr(),GL_INVALID_OPERATION);
        SET_ERROR_IF(objData.Ptr()->getDataType()!=SHADER_DATA,GL_INVALID_OPERATION);
        const char* src = ((ShaderParser*)objData.Ptr())->getOriginalSrc();
-       int srcLength = strlen(src);
+       int srcLength = 0;
+       if (src) {
+            srcLength = strlen(src);
+       }
 
        int returnLength = bufsize<srcLength ? bufsize-1 : srcLength;
-       strncpy(source,src, returnLength);
-       source[returnLength] = '\0';
+       if (returnLength) {
+            strncpy(source,src, returnLength);
+            source[returnLength] = '\0';
+       }
 
        if (length)
           *length = returnLength;
diff --git a/tools/emulator/opengl/host/libs/Translator/GLES_V2/ShaderParser.cpp b/tools/emulator/opengl/host/libs/Translator/GLES_V2/ShaderParser.cpp
index 8e5696a75..82cf5b507 100644
--- a/tools/emulator/opengl/host/libs/Translator/GLES_V2/ShaderParser.cpp
+++ b/tools/emulator/opengl/host/libs/Translator/GLES_V2/ShaderParser.cpp
@@ -3,6 +3,7 @@
 
 ShaderParser::ShaderParser():ObjectData(SHADER_DATA),
                              m_type(0),
+                             m_originalSrc(NULL),
                              m_parsedLines(NULL) {
     m_infoLog = new GLchar[1];
     m_infoLog[0] = '\0';
@@ -10,6 +11,7 @@ ShaderParser::ShaderParser():ObjectData(SHADER_DATA),
 
 ShaderParser::ShaderParser(GLenum type):ObjectData(SHADER_DATA), 
                                         m_type(type),
+                                        m_originalSrc(NULL),
                                         m_parsedLines(NULL) {
 
     m_infoLog = new GLchar[1];
@@ -20,6 +22,11 @@ void ShaderParser::setSrc(const Version& ver,GLsizei count,const GLchar** string
     for(int i = 0;i<count;i++){
         m_src.append(strings[i]);
     }
+    //store original source
+    if (m_originalSrc)
+        free(m_originalSrc);
+    m_originalSrc = strdup(m_src.c_str());
+
     clearParsedSrc();
 
     // parseGLSLversion must be called first since #version should be the
@@ -42,7 +49,7 @@ void ShaderParser::setSrc(const Version& ver,GLsizei count,const GLchar** string
     //XXX: Until proved otherwise, glsl doesn't know/use those precision macros, so we omit then
     parseOmitPrecision();
 #endif
-
+    parseLineNumbers();
     parseOriginalSrc();
 }
 const GLchar** ShaderParser::parsedLines() {
@@ -51,7 +58,12 @@ const GLchar** ShaderParser::parsedLines() {
 };
 
 const char* ShaderParser::getOriginalSrc(){
-    return m_src.c_str();
+    return m_originalSrc;
+}
+
+void ShaderParser::parseLineNumbers()
+{
+    m_parsedSrc += "#line 1\n";
 }
 
 void ShaderParser::parseOriginalSrc() {
@@ -173,9 +185,107 @@ void ShaderParser::parseOmitPrecision(){
                                          "#define lowp \n"
                                          "#define mediump \n"
                                          "#define highp \n"
-                                         "#define precision \n"
                                      };
     m_parsedSrc+=defines;
+
+    //
+    // parse the source and blank out precision statements
+    // which has the following syntax:
+    //   precision {qualifier} {type};
+    // where {qualifier} is one of lowp,mediump or hightp
+    // type is any valid GLES defined type (we do not check that here!)
+    // NOTE: This is needed in order to workaround driver bug in
+    //       Intel/Linux where the compiler does not get statement like
+    //       "float;", otherwise we could just define a macro named
+    //       precision to be empty.
+    //
+    const char *src = m_src.c_str();
+
+    enum { 
+        PRECISION,
+        QUALIFIER,
+        SEMICOLON
+    } statementState = PRECISION;
+    const char *precision = NULL;
+    const char *delimiter = NULL;
+    
+    enum {
+        PARSE_NONE,
+        PARSE_IN_C_COMMENT,
+        PARSE_IN_LINE_COMMENT
+    } parseState = PARSE_NONE;
+    const char *c = src;
+    const char *t = NULL;
+
+    #define IS_DELIMITER(c) ( (c) == ' ' || (c) == '\t' || (c) == '\r' || (c) == '\n' )
+    #define IS_TOKEN_START(c) ( ((c) >= 'a' && (c) <='z') || ((c) >= 'A' && (c) <= 'Z') )
+    #define IS_TOKEN_DELIMITER(c) ( IS_DELIMITER(c) || (c) == ';' )
+
+    while( c && *c != '\0') {
+        if (parseState == PARSE_IN_C_COMMENT) {
+            if (*c == '*' && *(c+1) == '/') {
+                parseState = PARSE_NONE;
+                c += 2;
+            }
+            else c++;
+        }
+        else if (parseState == PARSE_IN_LINE_COMMENT) {
+            if (*c == '\n') {
+                parseState = PARSE_NONE;
+            }
+            c++;
+        }
+        else if (*c == '/' && *(c+1) == '/') {
+            parseState = PARSE_IN_LINE_COMMENT;
+            c += 2;
+        }
+        else if (*c == '/' && *(c+1) == '*') {
+            parseState = PARSE_IN_C_COMMENT;
+            c += 2;
+        }
+        else if (t && IS_TOKEN_DELIMITER(*c)) {
+            int tokenLen = c - t;
+            switch (statementState) {
+            case PRECISION:
+                if (tokenLen == 9 && !strncmp(t,"precision",9)) {
+                    statementState = QUALIFIER;
+                    precision = t;
+                }
+                break;
+            case QUALIFIER:
+                if ((tokenLen == 4 && !strncmp(t,"lowp",4)) ||
+                    (tokenLen == 7 && !strncmp(t,"mediump",7)) ||
+                    (tokenLen == 5 && !strncmp(t,"highp",5))) {
+                    statementState = SEMICOLON;
+                }
+                else {
+                    statementState = PRECISION;
+                }
+                break;
+            case SEMICOLON:
+                if (*c == ';') {
+                    for (char *r = (char *)precision; r<=c ; ++r) {
+                        *r = ' '; //blank the character
+                    }
+                }
+                statementState = PRECISION; //search for the next precision line
+                break;
+            default:
+                break;
+            }
+            c++;
+            t = NULL;
+        }
+        else if (IS_DELIMITER(*c)) {
+            c++;
+        }
+        else {
+            if (!t && IS_TOKEN_START(*c)) {
+                t = c;
+            }
+            c++;
+        }
+    }
 }
 
 void ShaderParser::parseExtendDefaultPrecision(){
@@ -211,5 +321,7 @@ GLchar* ShaderParser::getInfoLog()
 
 ShaderParser::~ShaderParser(){
     clearParsedSrc();
+    if (m_originalSrc)
+        free(m_originalSrc);
     delete[] m_infoLog;
 }
diff --git a/tools/emulator/opengl/host/libs/Translator/GLES_V2/ShaderParser.h b/tools/emulator/opengl/host/libs/Translator/GLES_V2/ShaderParser.h
index 88e4b2ab5..8c0ff3e69 100644
--- a/tools/emulator/opengl/host/libs/Translator/GLES_V2/ShaderParser.h
+++ b/tools/emulator/opengl/host/libs/Translator/GLES_V2/ShaderParser.h
@@ -25,9 +25,11 @@ private:
     void parseBuiltinConstants();
     void parseOmitPrecision();
     void parseExtendDefaultPrecision();
+    void parseLineNumbers();
     void clearParsedSrc();
 
     GLenum      m_type;
+    char*       m_originalSrc;
     std::string m_src;
     std::string m_parsedSrc;
     GLchar*     m_parsedLines;